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Idelalisib: Drug information

Idelalisib: Drug information
(For additional information see "Idelalisib: Patient drug information")

For abbreviations, symbols, and age group definitions used in Lexicomp (show table)
Special Alerts
Accelerated Indications Withdrawn for Zydelig January 2022

Gilead has voluntarily withdrawn 2 indications for Zydelig (idelalisib) from the US market. These indications include the treatment of relapsed follicular B-cell non-Hodgkin lymphoma and relapsed small lymphocytic lymphoma. Continued approval for these indications was contingent on evidence confirming clinical benefit; however, enrollment into the confirmatory study has been an ongoing challenge. Zydelig is still approved for relapsed chronic lymphocytic leukemia.

Gilead continues to work collaboratively with the FDA to complete the withdrawal of the follicular B-cell non-Hodgkin lymphoma and small lymphocytic lymphoma indications in the United States and with health care providers to support those currently being treated with Zydelig. People receiving Zydelig for these indications should discuss their treatment options with their health care provider.

Further information is available at https://www.gilead.com/news-and-press/company-statements/gilead-statement-on-zydelig-us-indication-for-follicular-lymphoma-and-small-lymphocytic-leukemia.

ALERT: US Boxed Warning
Hepatotoxicity:

Fatal and/or serious hepatotoxicity occurred in 16% of idelalisib-treated patients. Monitor hepatic function prior to and during treatment. Interrupt and then reduce or discontinue idelalisib as recommended.

Severe diarrhea/colitis:

Fatal and/or serious and severe diarrhea or colitis occurred in 20% of idelalisib-treated patients. Monitor for the development of severe diarrhea or colitis. Interrupt and then reduce or discontinue idelalisib as recommended.

Pneumonitis:

Fatal and/or serious pneumonitis occurred in 4% of idelalisib-treated patients. Monitor for pulmonary symptoms and bilateral interstitial infiltrates. Interrupt or discontinue idelalisib as recommended.

Infection:

Fatal and/or serious infection occurred in 48% of idelalisib-treated patients. Monitor for signs and symptoms of infection. Interrupt idelalisib if infection is suspected.

Intestinal perforation:

Fatal and serious intestinal perforation can occur in idelalisib-treated patients across clinical trials. Discontinue idelalisib for intestinal perforation.

Brand Names: US
  • Zydelig
Brand Names: Canada
  • Zydelig
Pharmacologic Category
  • Antineoplastic Agent, Phosphatidylinositol 3-Kinase Inhibitor
Dosing: Adult

Note: Provide Pneumocystis jirovecii pneumonia prophylaxis throughout idelalisib treatment (and after discontinuation if infection risk persists).

Chronic lymphocytic leukemia, relapsed

Chronic lymphocytic leukemia, relapsed: Oral: 150 mg twice daily (in combination with rituximab); continue until disease progression or unacceptable toxicity (Furman 2014; Sharman 2019).

Missed doses: If the dose is missed by <6 hours, administer the missed dose as soon as possible and administer the next dose at the usual dosing time. If >6 hours, skip the missed dose and resume therapy with the next scheduled dose.

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Dosing: Kidney Impairment: Adult

CrCl ≥15 mL/minute: No dosage adjustment necessary (Jin 2015b).

CrCl <15 mL/minute: There are no dosage adjustments provided in the manufacturer’s labeling.

Dosing: Hepatic Impairment: Adult

Preexisting hepatic impairment:

Based on a pharmacokinetic study in patients with moderate and severe hepatic impairment (Child Pugh classes B and C) compared to healthy subjects, single oral doses of 150 mg were well tolerated; idelalisib and GS-563117 exposure differences were observed but not considered clinically relevant (Jin 2015a).

ALT or AST or bilirubin greater than the ULN: Dosage adjustment not necessary. However, limited safety data are available in patients with baseline ALT or AST >2.5 times ULN or bilirubin >1.5 times ULN. Monitor closely for toxicity.

Hepatotoxicity during treatment:

ALT/AST >3 to 5 times ULN or bilirubin >1.5 to 3 times ULN: Continue current idelalisib dose; monitor LFTs at least weekly until ALT/AST and/or bilirubin ≤1 times ULN.

ALT/AST >5 to 20 times ULN or bilirubin >3 to 10 times ULN: Temporarily interrupt idelalisib therapy. Monitor LFTs at least weekly until ALT/AST and/or bilirubin ≤1 times ULN, then may reinitiate therapy at 100 mg twice daily.

ALT/AST >20 times ULN or bilirubin >10 times ULN: Discontinue idelalisib permanently.

Recurrent hepatotoxicity: Discontinue idelalisib.

Dosing: Older Adult

Refer to adult dosing.

Dosing: Adjustment for Toxicity: Adult

Dermatologic toxicity:

Suspected Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), or drug reaction with eosinophilia and systemic symptoms (DRESS): Interrupt idelalisib until etiology is determined; discontinue idelalisib permanently if SJS, TEN, or DRESS are confirmed.

Other severe or life-threatening (≥ grade 3) cutaneous reactions: Permanently discontinue idelalisib.

Gastrointestinal toxicity:

Moderate diarrhea (increase of 4 to 6 stools/day over baseline): Continue current idelalisib dose; monitor at least weekly until resolved.

Severe diarrhea (increase of ≥7 stools/day over baseline) or hospitalization: Temporarily interrupt idelalisib; monitor at least weekly until resolved, then may reinitiate therapy at 100 mg twice daily.

Life-threatening diarrhea: Discontinue idelalisib permanently.

Intestinal perforation: Permanently discontinue idelalisib.

Hematologic toxicity:

Neutropenia:

ANC 1,000 to <1,500/mm3: Continue current idelalisib dose.

ANC 500 to <1,000/mm3: Continue current idelalisib dose; monitor blood counts at least weekly.

ANC <500/mm3: Temporarily interrupt idelalisib; monitor blood counts at least weekly until ANC ≥500/mm3, then may reinitiate therapy at 100 mg twice daily.

Thrombocytopenia:

Platelets 50,000 to <75,000/mm3: Continue current idelalisib dose.

Platelets 25,000 to <50,000/mm3: Continue current idelalisib dose; monitor platelet counts at least weekly.

Platelets <25,000/mm3: Temporarily interrupt idelalisib; monitor platelet counts at least weekly, may reinitiate therapy at 100 mg twice daily when platelets recover to ≥25,000/mm3.

Lymphocytosis: Dosage modification of idelalisib is not required (lymphocytosis is an idelalisib pharmacologic effect and should not be considered progressive disease in the absence of other clinical findings).

Hypersensitivity reactions, serious: Permanently discontinue idelalisib and manage appropriately.

Infection:

Sepsis, pneumonia, or other infection (grade 3 or higher): Interrupt idelalisib until infection has resolved.

Cytomegalovirus (CMV) infection or viremia: Interrupt idelalisib for evidence of active CMV infection of any grade or viremia (positive PCR or antigen test) until viremia has resolved. If idelalisib is reinitiated, monitor for CMV reactivation by PCR or antigen test at least monthly. Initiate antiviral therapy in CMV-infected patients with clinical symptoms of active CMV disease (Hallek 2018).

Pneumocystis jirovecii pneumonia (PCP) infection: Interrupt idelalisib for suspected PCP infection of any grade; permanently discontinue if PCP infection is confirmed.

Pulmonary toxicity: If pneumonitis is suspected, interrupt idelalisib and evaluate; permanently discontinue for symptomatic pneumonitis or organizing pneumonia of any severity thought to be associated with idelalisib (and initiate corticosteroids).

Other toxicity (not listed above): If other severe or life-threatening toxicities occur, interrupt idelalisib until toxicity is resolved. If the decision is made to resume idelalisib, reduce the dose to 100 mg twice daily. Discontinue idelalisib permanently if severe or life-threatening toxicities recur upon rechallenge.

Dosage Forms: US

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Zydelig: 100 mg [contains fd&c yellow #6(sunset yellow)alumin lake]

Zydelig: 150 mg

Generic Equivalent Available: US

No

Dosage Forms: Canada

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Zydelig: 100 mg [contains fd&c yellow #6(sunset yellow)alumin lake]

Zydelig: 150 mg

Prescribing and Access Restrictions

Available through specialty pharmacies. Further information may be obtained at http://www.zydeligaccessconnect.com/.

Medication Guide and/or Vaccine Information Statement (VIS)

An FDA-approved patient medication guide, which is available with the product information and as follows, must be dispensed with this medication:

Zydelig: https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/205858s016lbl.pdf#page=25

Administration: Adult

Oral: Administer with or without food. Swallow tablets whole.

Use: Labeled Indications

Chronic lymphocytic leukemia, relapsed: Treatment of relapsed chronic lymphocytic leukemia (CLL) (in combination with rituximab) when rituximab alone is appropriate therapy due to other comorbidities.

Limitations of use: Idelalisib is not indicated or recommended for first-line treatment of any patient, including patients with CLL, small lymphocytic lymphoma (SLL), follicular lymphoma (FL), and other indolent non-Hodgkin lymphomas. Idelalisib is not indicated and is not recommended in combination with bendamustine and/or rituximab for the treatment of FL, SLL, and other indolent non-Hodgkin lymphomas.

Medication Safety Issues
Sound-alike/look-alike issues:

Idelalisib may be confused with alpelisib, copanlisib, duvelisib, enasidenib, ibrutinib, IDArubicin, imatinib, ivosidenib, ixazomib, umbralisib.

Zydelig may be confused with Xtandi, Zejula, Zepzelca, Zytiga.

High alert medication:

This medication is in a class the Institute for Safe Medication Practices (ISMP) includes among its lists of drug classes which have a heightened risk of causing significant patient harm when used in error.

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reactions reported in adults with rituximab or ofatumumab combination therapy.

>10%:

Dermatologic: Skin rash (25%)

Gastrointestinal: Abdominal pain (18%), decreased appetite (16%), diarrhea (32% to 55%, including colitis; grades ≥3: 11%; severe diarrhea: 10% to 12%), nausea (27% to 34%; grades ≥3: 1%), vomiting (15%)

Hematologic & oncologic: Leukopenia (31%; grades 3/4: 8%), lymphocytopenia (21%; grades 3/4: 10%), neutropenia (65%; grades 3/4: 42%)

Hepatic: Increased serum alanine aminotransferase (39%), increased serum aspartate aminotransferase (28%)

Nervous system: Chills (25%), fatigue (34%)

Respiratory: Pneumonia (30%)

Miscellaneous: Fever (38% to 40%)

1% to 10%:

Endocrine & metabolic: Dehydration (6%)

Gastrointestinal: Gastrointestinal reflux disease (10%), oral herpes simplex infection (5%), stomatitis (6%; grades ≥3: 2%)

Genitourinary: Urinary tract infection (8%)

Infection: Severe infection (including cytomegalovirus disease [<1%], febrile neutropenia [5%], pneumonia due to Pneumocystis jirovecii [<1%], sepsis [8% to 9%])

Nervous system: Insomnia (9%), lethargy (5%), pain (7%)

Neuromuscular & skeletal: Arthralgia (8%)

Respiratory: Bronchitis (7%), pneumonitis (4%), sinusitis (8%)

Frequency not defined:

Gastrointestinal: Intestinal perforation

Hepatic: Hepatotoxicity (including severe hepatotoxicity)

Respiratory: Cough

Postmarketing:

Dermatologic: Erythematous rash (grades ≥3), exfoliative dermatitis (grades ≥3), macular eruption (grades ≥3), maculopapular rash (grades ≥3), papular rash (grades ≥3), pruritic rash (grades ≥3), Stevens-Johnson syndrome, toxic epidermal necrolysis

Hypersensitivity: Anaphylaxis, severe hypersensitivity reaction

Immunologic: Drug reaction with eosinophilia and systemic symptoms

Nervous system: Progressive multifocal leukoencephalopathy (Raisch 2016)

Contraindications

History of serious hypersensitivity reactions to idelalisib (including anaphylaxis) or any component of the formulation; history of toxic epidermal necrolysis.

Canadian labeling: Additional contraindications (not in the US labeling): Use in first-line chronic lymphocytic leukemia and early-line indolent non-Hodgkin lymphoma outside of a clinical trial

Warnings/Precautions

Concerns related to adverse effects:

• Bone marrow suppression: Grade 3 or 4 neutropenia occurs commonly with idelalisib. Lymphocytosis does not require dosage modification (lymphocytosis is a pharmacologic effect of idelalisib and should not be considered progressive disease in the absence of other clinical findings).

• Dermatologic toxicity: Cases of Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported (some fatal). Drug reaction with eosinophilia and systemic symptoms has also occurred. Other severe and/or life-threatening cutaneous reactions (grade 3 or higher), including exfoliative dermatitis, rash (generalized, erythematous, macular, maculopapular, papular, pruritic, exfoliative), and skin disorder, have been observed with idelalisib.

• GI events: Grade 3 or higher diarrhea or colitis have been reported in clinical trials (with idelalisib in combination with rituximab, and with off-label combination therapies). Diarrhea may occur at any time during therapy and responds poorly to antidiarrheal (antimotility) medications. The median time to resolution of diarrhea was 1 week to 1 month (following therapy interruption); corticosteroids were used in some cases to manage GI toxicity. Avoid concomitant use with other medications that may cause diarrhea. Serious and fatal intestinal perforation may occur. In some patients, perforation was preceded by moderate to severe diarrhea. Advise patients to promptly report any new or worsening abdominal pain, chills, fever, nausea, or vomiting.

• Hepatotoxicity: Fatal and/or serious hepatotoxicity has occurred. Hepatotoxicity has been reported with idelalisib in combination with rituximab, and with unapproved combination therapies. ALT/AST elevations >5 times ULN have occurred and were generally observed during the first 12 weeks of therapy; transaminase elevations were reversible upon therapy interruption. Hepatotoxicity may recur upon rechallenge, even with idelalisib resumed at a reduced dose.

• Hypersensitivity: Serious hypersensitivity reactions, including anaphylaxis, have been reported.

• Infections: Fatal and/or serious infection has occurred. Infections have been reported with idelalisib in combination with rituximab, and with unapproved combination therapies. Commonly reported infections include pneumonia, sepsis, and febrile neutropenia. Infections should be treated prior to initiating treatment with idelalisib. Serious cases (some fatal) of Pneumocystis jirovecii pneumonia and cytomegalovirus have been reported rarely.

• Pneumonitis: Fatal and serious pneumonitis may occur. Clinical manifestations include interstitial infiltrates and organizing pneumonia. The time to onset of symptoms ranged from less than 1 month to 15 months after therapy initiation. Symptoms may include cough, dyspnea, hypoxia, interstitial infiltrates, or an oxygen saturation decrease of more than 5%.

Special populations:

• Older age: Patients ≥65 years of age experienced a higher incidence of serious adverse reactions and a higher incidence of discontinuation due to adverse reactions (compared to patients <65 years of age).

Metabolism/Transport Effects

Substrate of BCRP/ABCG2, CYP3A4 (major), P-glycoprotein/ABCB1 (minor), UGT1A4; Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits CYP3A4 (strong)

Drug Interactions

Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the Lexicomp drug interactions program by clicking on the “Launch drug interactions program” link above.

5-Aminosalicylic Acid Derivatives: May enhance the myelosuppressive effect of Myelosuppressive Agents. Risk C: Monitor therapy

Abemaciclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Abemaciclib. Management: In patients taking abemaciclib at a dose of 200 mg or 150 mg twice daily, reduce the dose to 100 mg twice daily when combined with strong CYP3A4 inhibitors. In patients taking abemaciclib 100 mg twice daily, decrease the dose to 50 mg twice daily. Risk D: Consider therapy modification

Abrocitinib: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Risk X: Avoid combination

Acalabrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Acalabrutinib. Risk X: Avoid combination

Adagrasib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Adagrasib. Management: Avoid use of adagrasib and strong CYP3A4 inhibitors until adagrasib concentrations have reached stead state (ie, after approximately 8 days of therapy). Risk D: Consider therapy modification

Ado-Trastuzumab Emtansine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ado-Trastuzumab Emtansine. Specifically, strong CYP3A4 inhibitors may increase concentrations of the cytotoxic DM1 component. Management: Avoid concomitant use of ado-trastuzumab emtansine and strong CYP3A4 inhibitors when possible. Consider alternatives that do not inhibit CYP3A4 or consider administering after CYP3A4 inhibitor discontinuation. Monitor for toxicities if combined. Risk D: Consider therapy modification

Alfentanil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alfentanil. Management: If use of alfentanil and strong CYP3A4 inhibitors is necessary, consider dosage reduction of alfentanil until stable drug effects are achieved. Frequently monitor patients for respiratory depression and sedation when these agents are combined. Risk D: Consider therapy modification

Alfuzosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alfuzosin. Risk X: Avoid combination

Alitretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alitretinoin (Systemic). Management: Consider reducing the alitretinoin dose to 10 mg when used together with strong CYP3A4 inhibitors. Monitor for increased alitretinoin effects/toxicities if combined with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Almotriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Almotriptan. Management: Limit initial almotriptan dose to 6.25 mg and maximum dose to 12.5 mg in any 24-period when used with a strong CYP3A4 inhibitor. Avoid concurrent use in patients with impaired hepatic or renal function. Risk D: Consider therapy modification

Alosetron: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alosetron. Risk C: Monitor therapy

ALPRAZolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ALPRAZolam. Risk X: Avoid combination

Amiodarone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Amiodarone. Management: Consider alternatives to use of amiodarone and strong CYP3A4 inhibitors. If combined, monitor for increased amiodarone concentrations and toxicities. Risk D: Consider therapy modification

AmLODIPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of AmLODIPine. Risk C: Monitor therapy

Apixaban: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Apixaban. Risk C: Monitor therapy

Aprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Aprepitant. Risk X: Avoid combination

ARIPiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ARIPiprazole. Management: Aripiprazole dose reductions are required for indications other than major depressive disorder. Dose reductions vary based on formulation, CYP2D6 genotype, and use of CYP2D6 inhibitors. See full interaction monograph for details. Risk D: Consider therapy modification

ARIPiprazole Lauroxil: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of ARIPiprazole Lauroxil. Management: Decrease aripiprazole lauroxil dose to next lower strength if used with strong CYP3A4 inhibitors for over 14 days. No dose adjustment needed if using the lowest dose (441 mg). Max dose is 441 mg in CYP2D6 PMs or if also taking strong CYP2D6 inhibitors. Risk D: Consider therapy modification

Artemether and Lumefantrine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Artemether and Lumefantrine. Specifically, concentrations of dihydroartemisinin (DHA), the active metabolite of artemether may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Artemether and Lumefantrine. Risk C: Monitor therapy

Asciminib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Asciminib. Risk C: Monitor therapy

Astemizole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Astemizole. Risk X: Avoid combination

Asunaprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Asunaprevir. Risk X: Avoid combination

Atogepant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Atogepant. Management: The recommended dose of atogepant is 10 mg once daily when coadministered with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Atorvastatin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Atorvastatin. Risk C: Monitor therapy

Avacopan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avacopan. Management: Decrease the avacopan dose to 30 mg once daily during coadministration with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Avanafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avanafil. Risk X: Avoid combination

Avapritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avapritinib. Risk X: Avoid combination

Axitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Axitinib. Management: Avoid concurrent use of axitinib with any strong CYP3A inhibitor whenever possible. If a strong CYP3A inhibitor must be used with axitinib, a 50% axitinib dose reduction is recommended. Risk D: Consider therapy modification

Baricitinib: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Baricitinib. Risk X: Avoid combination

Barnidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Barnidipine. Risk X: Avoid combination

BCG (Intravesical): Myelosuppressive Agents may diminish the therapeutic effect of BCG (Intravesical). Risk X: Avoid combination

BCG Products: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of BCG Products. Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of BCG Products. Risk X: Avoid combination

Bedaquiline: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Bedaquiline. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bedaquiline. Management: Limit duration of concurrent use of bedaquiline with strong CYP3A4 inhibitors to no more than 14 days, unless the benefit of continued use outweighs the possible risks. Monitor for toxic effects of bedaquiline, including QTc interval prolongation. Risk D: Consider therapy modification

Benidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benidipine. Risk C: Monitor therapy

Benperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benperidol. Risk C: Monitor therapy

Benzhydrocodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benzhydrocodone. Specifically, the concentration of hydrocodone may be increased. Risk C: Monitor therapy

Betamethasone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Nasal). Risk C: Monitor therapy

Betamethasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Ophthalmic). Risk C: Monitor therapy

Betamethasone (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Systemic). Risk C: Monitor therapy

Betamethasone (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Topical). Risk C: Monitor therapy

Blonanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Blonanserin. Risk X: Avoid combination

Bortezomib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bortezomib. Risk C: Monitor therapy

Bosentan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bosentan. Risk C: Monitor therapy

Bosutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bosutinib. Risk X: Avoid combination

Brentuximab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brentuximab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Risk C: Monitor therapy

Brexpiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brexpiprazole. Management: Reduce brexpiprazole dose 50% with strong CYP3A4 inhibitors; reduce to 25% of usual if used with both a strong CYP3A4 inhibitor and a CYP2D6 inhibitor in patients not being treated for MDD, or strong CYP3A4 inhibitor used in a CYP2D6 poor metabolizer. Risk D: Consider therapy modification

Brigatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with strong CYP3A4 inhibitors when possible. If combination cannot be avoided, reduce the brigatinib dose by approximately 50%, rounding to the nearest tablet strength (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). Risk D: Consider therapy modification

Brincidofovir: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Brincidofovir. Risk C: Monitor therapy

Bromocriptine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bromocriptine. Management: Consider alternatives to the use of bromocriptine with strong CYP3A4 inhibitors. If combined, monitor closely for increased bromocriptine toxicities and consider bromocriptine dose reductions. Risk D: Consider therapy modification

Bromperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bromperidol. Risk C: Monitor therapy

Brotizolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brotizolam. Risk C: Monitor therapy

Budesonide (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Nasal). Risk C: Monitor therapy

Budesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Oral Inhalation). Management: Consider alternatives to this combination when possible. If combined, monitor for increased corticosteroid adverse effects during coadministration of inhaled budesonide and strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Budesonide (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Systemic). Management: Avoid the concomitant use of CYP3A4 inhibitors and oral budesonide. If patients receive both budesonide and a strong CYP3A4 inhibitor, they should be closely monitored for signs and symptoms of corticosteroid excess. Risk D: Consider therapy modification

Budesonide (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Topical). Risk X: Avoid combination

Buprenorphine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Buprenorphine. Risk C: Monitor therapy

BusPIRone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities if combined with strong CYP3A4 inhibitors. Dose adjustments of buspirone or a strong CYP3A4 inhibitor should be based on clinical assessment. Risk D: Consider therapy modification

Butorphanol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Butorphanol. Risk C: Monitor therapy

Cabazitaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabazitaxel. Management: Concurrent use of cabazitaxel with strong inhibitors of CYP3A4 should be avoided when possible. If such a combination must be used, consider a 25% reduction in the cabazitaxel dose. Risk D: Consider therapy modification

Cabozantinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabozantinib. Management: Avoid use of a strong CYP3A4 inhibitor with cabozantinib if possible. If combined, decrease cabozantinib capsules (Cometriq) by 40 mg from previous dose or decrease cabozantinib tablets (Cabometyx) by 20 mg from previous dose. Risk D: Consider therapy modification

Calcifediol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Calcifediol. Risk C: Monitor therapy

Calcitriol (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Calcitriol (Systemic). Risk C: Monitor therapy

Cannabidiol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabidiol. Risk C: Monitor therapy

Cannabis: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be increased. Risk C: Monitor therapy

Capmatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Capmatinib. Risk C: Monitor therapy

Cariprazine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Cariprazine. Specifically, concentrations of didesmethylcariprazine (DDCAR), the primary active metabolite of cariprazine, may increase. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cariprazine. Management: Decrease cariprazine dose 50% (4.5 mg to 1.5 mg or 3 mg; 1.5 mg to 1.5 mg every other day) if starting a strong CYP3A4 inhibitor. If on a strong CYP3A4 inhibitor, start cariprazine at 1.5 mg day 1, 0 mg day 2, then 1.5 mg daily. May increase to 3 mg daily Risk D: Consider therapy modification

Ceritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ceritinib. Management: Avoid this combination whenever possible. If combined, the ceritinib dose should be reduced by approximately one-third (to the nearest 150 mg). Resume the prior ceritinib dose after cessation of the strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Chloramphenicol (Ophthalmic): May enhance the adverse/toxic effect of Myelosuppressive Agents. Risk C: Monitor therapy

ChlordiazePOXIDE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ChlordiazePOXIDE. Risk C: Monitor therapy

Ciclesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ciclesonide (Oral Inhalation). Risk C: Monitor therapy

Cilnidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cilnidipine. Risk C: Monitor therapy

Cilostazol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cilostazol. Management: Decrease the dose of cilostazol to 50 mg twice daily when combined with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Cinacalcet: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cinacalcet. Risk C: Monitor therapy

Cisapride: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cisapride. Risk X: Avoid combination

Cladribine: May enhance the myelosuppressive effect of Myelosuppressive Agents. Risk X: Avoid combination

Cladribine: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Cladribine. Risk X: Avoid combination

Clindamycin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Clindamycin (Systemic). Risk C: Monitor therapy

Clofazimine: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk C: Monitor therapy

ClonazePAM: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ClonazePAM. Risk C: Monitor therapy

CloZAPine: Myelosuppressive Agents may enhance the adverse/toxic effect of CloZAPine. Specifically, the risk for neutropenia may be increased. Risk C: Monitor therapy

CloZAPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of CloZAPine. Risk C: Monitor therapy

Cobimetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cobimetinib. Risk X: Avoid combination

Coccidioides immitis Skin Test: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the diagnostic effect of Coccidioides immitis Skin Test. Management: Consider discontinuing these oncologic agents several weeks prior to coccidioides immitis skin antigen testing to increase the likelihood of accurate diagnostic results. Risk D: Consider therapy modification

Codeine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Codeine. Risk C: Monitor therapy

Colchicine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Colchicine. Management: Colchicine is contraindicated in patients with impaired renal or hepatic function who are also receiving a strong CYP3A4 inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. See interaction monograph for details. Risk D: Consider therapy modification

Conivaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Conivaptan. Risk X: Avoid combination

Copanlisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Copanlisib. Management: If concomitant use of copanlisib and strong CYP3A4 inhibitors cannot be avoided, reduce the copanlisib dose to 45 mg. Monitor patients for increased copanlisib effects/toxicities. Risk D: Consider therapy modification

Cortisone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cortisone. Risk C: Monitor therapy

COVID-19 Vaccine (Adenovirus Vector): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of COVID-19 Vaccine (Adenovirus Vector). Management: Administer a 2nd dose using an mRNA COVID-19 vaccine (at least 4 weeks after the primary vaccine dose) and a bivalent booster dose (at least 2 months after the additional mRNA dose or any other boosters). Risk D: Consider therapy modification

COVID-19 Vaccine (Inactivated Virus): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of COVID-19 Vaccine (Inactivated Virus). Risk C: Monitor therapy

COVID-19 Vaccine (mRNA): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of COVID-19 Vaccine (mRNA). Management: Give a 3-dose primary series for all patients aged 6 months and older taking immunosuppressive medications or therapies. Booster doses are recommended for certain age groups. See CDC guidance for details. Risk D: Consider therapy modification

COVID-19 Vaccine (Subunit): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of COVID-19 Vaccine (Subunit). Risk C: Monitor therapy

COVID-19 Vaccine (Virus-like Particles): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of COVID-19 Vaccine (Virus-like Particles). Risk C: Monitor therapy

Crizotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Crizotinib. Management: Avoid concomitant use of crizotinib and strong CYP3A4 inhibitors whenever possible. If combined use cannot be avoided, crizotinib dose reductions are required, which vary according to indication. See full interaction monograph for details. Risk D: Consider therapy modification

CycloSPORINE (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of CycloSPORINE (Systemic). Management: Monitor cyclosporine serum concentrations and clinical cyclosporine closely with concurrent use of any strong CYP3A4 inhibitor. Cyclosporine dose reductions and/or prolongation of the dosing interval will likely be required. Risk D: Consider therapy modification

CYP3A4 Inducers (Moderate): May decrease the serum concentration of Idelalisib. Risk C: Monitor therapy

CYP3A4 Inducers (Strong): May decrease the serum concentration of Idelalisib. Risk X: Avoid combination

CYP3A4 Inhibitors (Strong): May increase the serum concentration of Idelalisib. Management: Use alternative therapies that are not strong CYP3A4 inhibitors whenever possible. If unable to use alternative drugs, monitor patients more frequently for idelalisib toxicities. Risk D: Consider therapy modification

Cyproterone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cyproterone. Risk C: Monitor therapy

Dabrafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dabrafenib. Management: Consider alternatives to any strong CYP3A4 inhibitor for patients being treated with dabrafenib. If such a combination cannot be avoided, monitor closely for evidence of dabrafenib-related adverse effects. Risk D: Consider therapy modification

Daclatasvir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Daclatasvir. Management: Decrease the daclatasvir dose to 30 mg once daily if combined with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Dapoxetine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dapoxetine. Risk X: Avoid combination

Daridorexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Daridorexant. Risk X: Avoid combination

Darifenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Darifenacin. Management: Limit the darifenacin dose to no more than 7.5 mg daily if combined with strong CYP3A4 inhibitors. Monitor patients for increased darifenacin toxicities (eg, dry mouth, constipation, headache, CNS effects) when these agents are combined. Risk D: Consider therapy modification

Dasatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dasatinib. Management: This combination should be avoided if possible. If combined, decrease dasatinib dose from 140 mg to 40 mg, 100 mg to 20 mg, or 70 mg to 20 mg. For patients taking 60 mg or 40 mg daily, stop dasatinib until the CYP3A4 inhibitor is discontinued. Risk D: Consider therapy modification

Deferiprone: Myelosuppressive Agents may enhance the neutropenic effect of Deferiprone. Management: Avoid the concomitant use of deferiprone and myelosuppressive agents whenever possible. If this combination cannot be avoided, monitor the absolute neutrophil count more closely. Risk D: Consider therapy modification

Deflazacort: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Deflazacort. Management: Administer one third of the recommended deflazacort dose when used together with a strong or moderate CYP3A4 inhibitor. Risk D: Consider therapy modification

Delamanid: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Delamanid. Management: Increase ECG monitoring frequency if delamanid is combined with strong CYP3A4 inhibitors due to the risk for QTc interval prolongation. Continue frequent ECG assessments throughout full delamanid treatment period. Risk D: Consider therapy modification

Dengue Tetravalent Vaccine (Live): Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Dengue Tetravalent Vaccine (Live). Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Dengue Tetravalent Vaccine (Live). Risk X: Avoid combination

Denosumab: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Management: Consider the risk of serious infections versus the potential benefits of coadministration of denosumab and immunosuppressants. If combined, monitor patients for signs/symptoms of serious infections. Risk D: Consider therapy modification

Deucravacitinib: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Risk X: Avoid combination

DexAMETHasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DexAMETHasone (Ophthalmic). Risk C: Monitor therapy

DexAMETHasone (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DexAMETHasone (Systemic). Risk C: Monitor therapy

DiazePAM: CYP3A4 Inhibitors (Strong) may increase the serum concentration of DiazePAM. Risk C: Monitor therapy

DilTIAZem: CYP3A4 Inhibitors (Strong) may increase the serum concentration of DilTIAZem. Risk C: Monitor therapy

Dipyrone: May enhance the adverse/toxic effect of Myelosuppressive Agents. Specifically, the risk for agranulocytosis and pancytopenia may be increased Risk X: Avoid combination

Disopyramide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Disopyramide. Risk C: Monitor therapy

DOCEtaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOCEtaxel. Management: Avoid the concomitant use of docetaxel and strong CYP3A4 inhibitors when possible. If combined use is unavoidable, consider a 50% docetaxel dose reduction and monitor for increased docetaxel toxicities. Risk D: Consider therapy modification

Dofetilide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dofetilide. Risk C: Monitor therapy

Domperidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Domperidone. Risk X: Avoid combination

Doxazosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Doxazosin. Risk C: Monitor therapy

Doxercalciferol: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Doxercalciferol. Risk C: Monitor therapy

DOXOrubicin (Conventional): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOXOrubicin (Conventional). Risk X: Avoid combination

DOXOrubicin (Liposomal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOXOrubicin (Liposomal). Risk C: Monitor therapy

Dronabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronabinol. Risk C: Monitor therapy

Dronedarone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronedarone. Risk X: Avoid combination

Dutasteride: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dutasteride. Risk C: Monitor therapy

Duvelisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Duvelisib. Management: Reduce the dose of duvelisib to 15 mg twice a day when used together with a strong CYP3A4 inhibitor. Monitor closely for evidence of altered response to treatment. Risk D: Consider therapy modification

Dydrogesterone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dydrogesterone. Risk C: Monitor therapy

Ebastine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ebastine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ebastine. Risk C: Monitor therapy

Efonidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Efonidipine. Risk C: Monitor therapy

Elagolix: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elagolix. Management: Use of the elagolix 200 mg twice daily dose with a strong CYP3A4 inhibitor for longer than 1 month is not recommended. Limit combined use of the elagolix 150 mg once daily dose with a strong CYP3A4 inhibitor to a maximum of 6 months. Risk D: Consider therapy modification

Elagolix, Estradiol, and Norethindrone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elagolix, Estradiol, and Norethindrone. Elagolix, Estradiol, and Norethindrone may decrease the serum concentration of CYP3A4 Inhibitors (Strong). Specifically, concentrations of strong CYP3A4 inhibitors that are also CYP3A4 substrates may be decreased. Risk X: Avoid combination

Elbasvir and Grazoprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elbasvir and Grazoprevir. Management: Consider alternatives to this combination when possible. If combined, monitor for increased elbasvir/grazoprevir toxicities, including ALT elevations. Risk D: Consider therapy modification

Eletriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eletriptan. Risk X: Avoid combination

Elexacaftor, Tezacaftor, and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elexacaftor, Tezacaftor, and Ivacaftor. Management: When combined with strong CYP3A4 inhibitors, administer two elexacaftor/tezacaftor/ivacaftor tablets (100 mg/50 mg/75 mg) in the morning, twice a week, approximately 3 to 4 days apart. No evening doses of ivacaftor (150 mg) alone should be administered. Risk D: Consider therapy modification

Eliglustat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eliglustat. Management: Reduce eliglustat dose to 84 mg daily in CYP2D6 EMs when used with strong CYP3A4 inhibitors. Use of strong CYP3A4 inhibitors is contraindicated in CYP2D6 IMs, PMs, or in CYP2D6 EMs who are also taking strong or moderate CYP2D6 inhibitors. Risk D: Consider therapy modification

Encorafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Encorafenib. Management: Avoid use of encorafenib and strong CYP3A4 inhibitors when possible. If combined, decrease encorafenib from 450 mg to 150 mg; or from 300 mg, 225 mg, or 150 mg to 75 mg. Once the CYP3A4 inhibitor is discontinued for 3 to 5 half-lives, resume prior dose. Risk D: Consider therapy modification

Entrectinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Entrectinib. Management: Avoid strong CYP3A4 inhibitors during treatment with entrectinib when possible. If combined in adults and those 12 yrs of age or older with a BSA of at least 1.5 square meters, reduce dose to 100 mg/day. Avoid if BSA is less than 1.5 square meters. Risk D: Consider therapy modification

Eplerenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eplerenone. Risk X: Avoid combination

Erdafitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erdafitinib. Management: Avoid concomitant use of erdafitinib and strong CYP3A4 inhibitors when possible. If combined, monitor closely for erdafitinib adverse reactions and consider dose modifications accordingly. Risk D: Consider therapy modification

Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates). Risk X: Avoid combination

Erlotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erlotinib. Management: Avoid use of this combination when possible. When the combination must be used, monitor the patient closely for the development of erlotinib-associated adverse reactions, and if such severe reactions occur, reduce the erlotinib dose (in 50 mg decrements). Risk D: Consider therapy modification

Erythromycin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erythromycin (Systemic). Management: Consider alternatives to this combination when possible. If combined, monitor for increased erythromycin effects and toxicities, including QTc interval prolongation. Risk D: Consider therapy modification

Estrogen Derivatives: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Estrogen Derivatives. Risk C: Monitor therapy

Eszopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eszopiclone. Management: Limit the eszopiclone dose to 2 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased eszopiclone effects and toxicities (eg, somnolence, drowsiness, CNS depression). Risk D: Consider therapy modification

Etizolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Etizolam. Risk C: Monitor therapy

Etravirine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Etravirine. Risk C: Monitor therapy

Everolimus: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Everolimus. Management: Consider avoiding use of strong CYP3A4 inhibitors with everolimus. If combined, closely monitor for increased everolimus serum concentrations and toxicities. Everolimus dose reductions will likely be required. Risk D: Consider therapy modification

Evogliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Evogliptin. Risk C: Monitor therapy

Fedratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fedratinib. Management: Consider alternatives when possible. If used together, decrease fedratinib dose to 200 mg/day. After the inhibitor is stopped, increase fedratinib to 300 mg/day for the first 2 weeks and then to 400 mg/day as tolerated. Risk D: Consider therapy modification

Felodipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Felodipine. Management: Consider using lower felodipine doses when combined with strong CYP3A4 inhibitors. Monitor patients for increased felodipine effects and toxicities (eg, hypotension, edema) when combined. Risk D: Consider therapy modification

FentaNYL: CYP3A4 Inhibitors (Strong) may increase the serum concentration of FentaNYL. Management: Consider fentanyl dose reductions when combined with a strong CYP3A4 inhibitor. Monitor for respiratory depression and sedation. Upon discontinuation of a CYP3A4 inhibitor, consider a fentanyl dose increase; monitor for signs and symptoms of withdrawal. Risk D: Consider therapy modification

Fesoterodine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fesoterodine. Management: Limit fesoterodine doses to 4 mg daily in patients who are also receiving strong CYP3A4 inhibitors. This combination is not recommended in pediatric patients weighing 25 kg up to 35 kg. Risk D: Consider therapy modification

Fexinidazole: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk X: Avoid combination

Fexinidazole: Myelosuppressive Agents may enhance the myelosuppressive effect of Fexinidazole. Risk X: Avoid combination

Filgotinib: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Risk X: Avoid combination

Finerenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Finerenone. Risk X: Avoid combination

Flibanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Flibanserin. Management: Use of flibanserin with strong CYP3A4 inhibitors is contraindicated. If starting flibanserin, start 2 weeks after the last dose of the CYP3A4 inhibitor. If starting a CYP3A4 inhibitor, start 2 days after the last dose of flibanserin. Risk X: Avoid combination

Fluticasone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Nasal). Risk X: Avoid combination

Fluticasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Oral Inhalation). Management: Consider alternatives to this combination if possible. Coadministration of fluticasone propionate and strong CYP3A4 inhibitors is not recommended. If combined, monitor patients for systemic corticosteroid adverse effects (eg, adrenal suppression). Risk D: Consider therapy modification

Fluticasone (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Topical). Risk C: Monitor therapy

Fosamprenavir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fosamprenavir. Risk C: Monitor therapy

Fosaprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fosaprepitant. Risk X: Avoid combination

Fostamatinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fostamatinib. Risk C: Monitor therapy

Fusidic Acid (Systemic): May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Risk X: Avoid combination

Galantamine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Galantamine. Risk C: Monitor therapy

Gefitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Gefitinib. Risk C: Monitor therapy

Gilteritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Gilteritinib. Management: Consider alternatives to the use of a strong CYP3A4 inhibitor with gilteritinib. If the combination cannot be avoided, monitor more closely for evidence of gilteritinib toxicities. Risk D: Consider therapy modification

Glasdegib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Glasdegib. Management: Consider alternatives to this combination when possible. If the combination must be used, monitor closely for evidence of QT interval prolongation and other adverse reactions to glasdegib. Risk D: Consider therapy modification

GuanFACINE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of GuanFACINE. Management: Reduce the extended-release guanfacine dose 50% when combined with a strong CYP3A4 inhibitor. Monitor for increased guanfacine toxicities when these agents are combined. Risk D: Consider therapy modification

Halofantrine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Halofantrine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for halofantrine toxicities, including QTc interval prolongation. Risk D: Consider therapy modification

Haloperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Haloperidol. Risk C: Monitor therapy

Hormonal Contraceptives: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Hormonal Contraceptives. Risk C: Monitor therapy

HYDROcodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of HYDROcodone. Risk C: Monitor therapy

Hydrocortisone (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Hydrocortisone (Systemic). Risk C: Monitor therapy

Ibrexafungerp: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ibrexafungerp. Management: Decrease the ibrexafungerp dose to 150 mg every 12 hours for 2 doses in patients receiving strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Ibrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ibrutinib. Management: Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for 7 days or less), interrupt ibrutinib therapy until the strong CYP3A4 inhibitor is discontinued. Risk X: Avoid combination

Ifosfamide: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ifosfamide. Risk C: Monitor therapy

Iloperidone: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Iloperidone. Specifically, concentrations of the metabolites P88 and P95 may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Iloperidone. Management: Reduce iloperidone dose by half when administered with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Imatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imatinib. Risk C: Monitor therapy

Imidafenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imidafenacin. Risk C: Monitor therapy

Inebilizumab: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Inebilizumab. Risk C: Monitor therapy

Infigratinib: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Infigratinib. CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Infigratinib. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Infigratinib. Risk X: Avoid combination

Influenza Virus Vaccines: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Influenza Virus Vaccines. Management: Administer influenza vaccines at least 2 weeks prior to initiating immunosuppressants if possible. If vaccination occurs less than 2 weeks prior to or during therapy, revaccinate at least 3 months after therapy discontinued if immune competence restored. Risk D: Consider therapy modification

Irinotecan Products: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Irinotecan Products. Specifically, serum concentrations of SN-38 may be increased. Management: Avoid administration of strong CYP3A4 inhibitors during and within 1 week prior to irinotecan administration, unless no therapeutic alternatives to these agents exist. If combined, monitor closely for increased irinotecan toxicities. Risk D: Consider therapy modification

Isavuconazonium Sulfate: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Isavuconazonium Sulfate. Specifically, CYP3A4 Inhibitors (Strong) may increase isavuconazole serum concentrations. Risk X: Avoid combination

Isradipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Isradipine. Risk C: Monitor therapy

Istradefylline: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Istradefylline. Management: Limit the maximum istradefylline dose to 20 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased istradefylline effects/toxicities. Risk D: Consider therapy modification

Ivabradine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivabradine. Risk X: Avoid combination

Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full drug interaction monograph content for age- and weight-specific recommendations. Risk D: Consider therapy modification

Ivosidenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivosidenib. Management: Avoid use of a strong CYP3A4 inhibitor with ivosidenib whenever possible. When combined use is required, reduce the ivosidenib dose to 250 mg once daily and monitor for increased ivosidenib toxicities, including QTc interval prolongation. Risk D: Consider therapy modification

Ixabepilone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ixabepilone. Management: Avoid use of ixabepilone and strong CYP3A4 inhibitors when possible. If combined, reduce the ixabepilone dose to 20 mg/m2. The previous ixabepilone dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Ketamine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ketamine. Risk C: Monitor therapy

Lacidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lacidipine. Risk C: Monitor therapy

Lapatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lapatinib. Management: Avoid use of lapatinib and strong CYP3A4 inhibitors when possible. If combined, a reduced lapatinib dose of 500 mg daily should be considered. The previous lapatinib dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Larotrectinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Larotrectinib. Management: Avoid use of strong CYP3A4 inhibitors with larotrectinib. If this combination cannot be avoided, reduce the larotrectinib dose by 50%. Increase to previous dose after stopping the inhibitor after a period of 3 to 5 times the inhibitor's half-life. Risk D: Consider therapy modification

Lefamulin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lefamulin. Management: Avoid concomitant use of lefamulin tablets and strong inhibitors of CYP3A4. Risk X: Avoid combination

Leflunomide: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Leflunomide. Management: Increase the frequency of chronic monitoring of platelet, white blood cell count, and hemoglobin or hematocrit to monthly, instead of every 6 to 8 weeks, if leflunomide is coadministered with immunosuppressive agents. Risk D: Consider therapy modification

Lemborexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lemborexant. Risk X: Avoid combination

Lercanidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lercanidipine. Risk X: Avoid combination

Leuprolide and Norethindrone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Leuprolide and Norethindrone. Specifically, concentrations of norethindrone may increase. Risk C: Monitor therapy

Levamlodipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levamlodipine. Risk C: Monitor therapy

Levobupivacaine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levobupivacaine. Risk C: Monitor therapy

Levoketoconazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levoketoconazole. Risk X: Avoid combination

Levomethadone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levomethadone. Risk C: Monitor therapy

Levomilnacipran: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levomilnacipran. Management: The dose of levomilnacipran should not exceed 80 mg once daily when used with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Lidocaine (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lidocaine (Systemic). Risk C: Monitor therapy

Lomitapide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lomitapide. Risk X: Avoid combination

Lonafarnib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lonafarnib. Risk X: Avoid combination

Lorlatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lorlatinib. Management: Avoid use of lorlatinib with strong CYP3A4 inhibitors. If the combination cannot be avoided, reduce the lorlatinib dose from 100 mg once daily to 75 mg once daily, or from 75 mg once daily to 50 mg once daily. Risk D: Consider therapy modification

Lovastatin: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Lovastatin. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lovastatin. Risk X: Avoid combination

Lumateperone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lumateperone. Management: Limit the lumateperone dose to 10.5 mg once daily when used with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Lurasidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lurasidone. Risk X: Avoid combination

Lurbinectedin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lurbinectedin. Risk X: Avoid combination

Macitentan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Macitentan. Risk X: Avoid combination

Manidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Manidipine. Management: Consider avoiding concomitant use of manidipine and strong CYP3A4 inhibitors. If combined, monitor closely for increased manidipine effects and toxicities. Manidipine dose reductions may be required. Risk D: Consider therapy modification

Maraviroc: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Maraviroc. Management: Reduce maraviroc to 150mg twice/day in adult and pediatrics weighing 40kg or more. See full interaction monograph for dose adjustments in pediatrics weighing 10 to less than 40kg. Do not use if CrCl less than 30mL/min or in those weighing less than 10 kg. Risk D: Consider therapy modification

Mavacamten: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mavacamten. Risk X: Avoid combination

Mefloquine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mefloquine. Risk C: Monitor therapy

Meperidine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Meperidine. Risk C: Monitor therapy

Methadone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Methadone. Management: If coadministration with strong CYP3A4 inhibitors is necessary, consider methadone dose reductions until stable effects are achieved. Monitor patients closely for respiratory depression and sedation. Risk D: Consider therapy modification

MethylPREDNISolone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MethylPREDNISolone. Risk C: Monitor therapy

Midazolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Midazolam. Management: Avoid use of nasal midazolam and strong CYP3A4 inhibitors whenever possible, and consider alternatives to use with other routes of midazolam (oral, IV, IM). If combined, consider lower midazolam doses and monitor for increased midazolam toxicities. Risk D: Consider therapy modification

Midostaurin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Midostaurin. Management: Seek alternatives to the concomitant use of midostaurin and strong CYP3A4 inhibitors if possible. If concomitant use cannot be avoided, monitor patients for increased risk of adverse reactions. Risk D: Consider therapy modification

MiFEPRIStone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MiFEPRIStone. Management: For treatment of hyperglycemia in Cushing's syndrome, start mifepristone at 300 mg/day, may titrate to a maximum of 900 mg/day. If starting a strong CYP3A4 inhibitor and taking > 300 mg/day mifepristone, decrease the mifepristone dose by 300 mg/day. Risk D: Consider therapy modification

Mirodenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirodenafil. Management: Consider using a lower dose of mirodenafil when used with strong CYP3A4 inhibitors. Monitor for increased mirodenafil effects/toxicities with the use of this combination. Risk D: Consider therapy modification

Mirtazapine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirtazapine. Risk C: Monitor therapy

Mirvetuximab Soravtansine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirvetuximab Soravtansine. Risk C: Monitor therapy

Mitapivat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mitapivat. Risk X: Avoid combination

Mobocertinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Mobocertinib. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mobocertinib. Risk X: Avoid combination

Mometasone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mometasone (Nasal). Risk C: Monitor therapy

Mometasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mometasone (Oral Inhalation). Risk C: Monitor therapy

Mometasone (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mometasone (Topical). Risk C: Monitor therapy

Naldemedine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naldemedine. Risk C: Monitor therapy

Nalfurafine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nalfurafine. Risk C: Monitor therapy

Naloxegol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naloxegol. Risk X: Avoid combination

Natalizumab: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Natalizumab. Risk X: Avoid combination

Neratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Neratinib. Risk X: Avoid combination

NiCARdipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of NiCARdipine. Risk C: Monitor therapy

NIFEdipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of NIFEdipine. Management: Consider alternatives to this combination when possible. If combined, initiate nifedipine at the lowest dose available and monitor patients closely for increased nifedipine effects and toxicities (eg, hypotension, edema). Risk D: Consider therapy modification

Nilotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nilotinib. Management: Avoid if possible. If combination needed, decrease nilotinib to 300 mg once/day for patients with resistant or intolerant Ph+ CML or to 200 mg once/day for patients with newly diagnosed Ph+ CML in chronic phase. Risk D: Consider therapy modification

Nilvadipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nilvadipine. Risk C: Monitor therapy

NiMODipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of NiMODipine. Risk X: Avoid combination

Nisoldipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nisoldipine. Risk X: Avoid combination

Nitrendipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nitrendipine. Risk C: Monitor therapy

Ocrelizumab: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Ocrelizumab. Risk C: Monitor therapy

Ofatumumab: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Ofatumumab. Risk C: Monitor therapy

Olaparib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Olaparib. Management: Avoid use of strong CYP3A4 inhibitors with olaparib, if possible. If such concurrent use cannot be avoided, the dose of olaparib tablets should be reduced to 100 mg twice daily and the dose of olaparib capsules should be reduced to 150 mg twice daily. Risk D: Consider therapy modification

Oliceridine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Oliceridine. Risk C: Monitor therapy

Olmutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Olmutinib. Risk C: Monitor therapy

Orelabrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Orelabrutinib. Risk X: Avoid combination

Osilodrostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Osilodrostat. Management: Reduce osilodrostat dose by 50% during coadministration with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Ospemifene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ospemifene. Risk C: Monitor therapy

Oxybutynin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Oxybutynin. Risk C: Monitor therapy

OxyCODONE: CYP3A4 Inhibitors (Strong) may enhance the adverse/toxic effect of OxyCODONE. CYP3A4 Inhibitors (Strong) may increase the serum concentration of OxyCODONE. Serum concentrations of the active metabolite oxymorphone may also be increased. Risk C: Monitor therapy

PACLitaxel (Conventional): CYP3A4 Inhibitors (Strong) may increase the serum concentration of PACLitaxel (Conventional). Risk C: Monitor therapy

PACLitaxel (Protein Bound): CYP3A4 Inhibitors (Strong) may increase the serum concentration of PACLitaxel (Protein Bound). Risk C: Monitor therapy

Pacritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pacritinib. Risk X: Avoid combination

Palbociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Palbociclib. Management: Avoid concurrent use of strong CYP3A4 inhibitors with palbociclib when possible. If the use of a strong CYP3A4 inhibitor cannot be avoided, decrease the palbociclib dose to 75 mg/day. Risk D: Consider therapy modification

Palovarotene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Palovarotene. Risk X: Avoid combination

Panobinostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Panobinostat. Management: Reduce the panobinostat dose to 10 mg when it must be used with a strong CYP3A4 inhibitor. Monitor patient response to therapy closely for evidence of more severe adverse effects related to panobinostat therapy. Risk D: Consider therapy modification

Parecoxib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Parecoxib. Specifically, serum concentrations of the active moiety valdecoxib may be increased. Risk C: Monitor therapy

Paricalcitol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Paricalcitol. Risk C: Monitor therapy

PAZOPanib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PAZOPanib. Management: Avoid concurrent use of pazopanib with strong inhibitors of CYP3A4 whenever possible. If it is not possible to avoid such a combination, reduce pazopanib dose to 400 mg. Further dose reductions may also be required if adverse reactions occur. Risk D: Consider therapy modification

Pemigatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pemigatinib. Management: If combined use cannot be avoided, reduce the pemigatinib dose from 13.5 mg daily to 9 mg daily, or from 9 mg daily to 4.5 mg daily. Resume prior pemigatinib dose after stopping the strong inhibitor once 3 half-lives of the inhibitor has passed. Risk D: Consider therapy modification

Pexidartinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pexidartinib. Management: Avoid use of pexidartinib with strong CYP3A4 inhibitors if possible. If combined use cannot be avoided, pexidartinib dose should be reduced. Decrease 800 mg or 600 mg daily doses to 200 mg twice daily. Decrease doses of 400 mg per day to 200 mg once daily Risk D: Consider therapy modification

Pidotimod: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Pidotimod. Risk C: Monitor therapy

Pimavanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimavanserin. Management: Decrease the pimavanserin dose to 10 mg daily when combined with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Pimecrolimus: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Risk X: Avoid combination

Pimozide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimozide. Risk X: Avoid combination

Piperaquine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Piperaquine. Risk C: Monitor therapy

Pneumococcal Vaccines: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Pneumococcal Vaccines. Risk C: Monitor therapy

Polatuzumab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Polatuzumab Vedotin. Exposure to unconjugated MMAE, the cytotoxic small molecule component of polatuzumab vedotin, may be increased. Risk C: Monitor therapy

Poliovirus Vaccine (Live/Trivalent/Oral): Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Poliovirus Vaccine (Live/Trivalent/Oral). Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Poliovirus Vaccine (Live/Trivalent/Oral). Risk X: Avoid combination

Polymethylmethacrylate: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the potential for allergic or hypersensitivity reactions to Polymethylmethacrylate. Management: Use caution when considering use of bovine collagen-containing implants such as the polymethylmethacrylate-based Bellafill brand implant in patients who are receiving immunosuppressants. Consider use of additional skin tests prior to administration. Risk D: Consider therapy modification

PONATinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PONATinib. Management: Avoid concomitant use if possible. If combined, reduce ponatinib dose as follows: If taking 45 mg, reduce to 30 mg; if taking 30 mg, reduce to 15 mg; if taking 15 mg, reduce to 10 mg. If taking 10 mg, avoid concomitant use with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Pralsetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pralsetinib. Risk X: Avoid combination

Prazepam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Prazepam. Risk C: Monitor therapy

Praziquantel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Praziquantel. Risk C: Monitor therapy

PrednisoLONE (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of PrednisoLONE (Systemic). Risk C: Monitor therapy

PredniSONE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PredniSONE. Risk C: Monitor therapy

Promazine: May enhance the myelosuppressive effect of Myelosuppressive Agents. Risk C: Monitor therapy

Propafenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Propafenone. Risk C: Monitor therapy

QUEtiapine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of QUEtiapine. Management: In quetiapine treated patients, reduce quetiapine to one-sixth of original dose after starting a strong CYP3A4 inhibitor. In those on strong CYP3A4 inhibitors, start quetiapine at lowest dose and up-titrate as needed. Risk D: Consider therapy modification

QuiNIDine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of QuiNIDine. Risk C: Monitor therapy

Quinidine (Non-Therapeutic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Quinidine (Non-Therapeutic). Risk C: Monitor therapy

QuiNINE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of QuiNINE. Risk C: Monitor therapy

Rabies Vaccine: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Rabies Vaccine. Management: Complete rabies vaccination at least 2 weeks before initiation of immunosuppressant therapy if possible. If combined, check for rabies antibody titers, and if vaccination is for post exposure prophylaxis, administer a 5th dose of the vaccine. Risk D: Consider therapy modification

Radotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Radotinib. Risk X: Avoid combination

Ramelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ramelteon. Risk C: Monitor therapy

Ranolazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ranolazine. Risk X: Avoid combination

Reboxetine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Reboxetine. Risk C: Monitor therapy

Red Yeast Rice: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Red Yeast Rice. Specifically, concentrations of lovastatin and related compounds found in Red Yeast Rice may be increased. Risk X: Avoid combination

Regorafenib: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Regorafenib. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Regorafenib. Risk X: Avoid combination

Repaglinide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Repaglinide. Risk C: Monitor therapy

Retapamulin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Retapamulin. Management: The use of retapamulin with strong CYP3A4 inhibitors is not recommended in patients less than 2 years old. No action is required in other populations. Risk C: Monitor therapy

Ribociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ribociclib. Management: Avoid use of ribociclib with strong CYP3A4 inhibitors when possible; if combined use cannot be avoided, reduce ribociclib dose to 400 mg once daily. Risk D: Consider therapy modification

Rifabutin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rifabutin. Risk C: Monitor therapy

Rilpivirine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rilpivirine. Risk C: Monitor therapy

Rimegepant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rimegepant. Risk X: Avoid combination

Riociguat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Riociguat. Risk C: Monitor therapy

Ripretinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ripretinib. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ripretinib. Risk C: Monitor therapy

RisperiDONE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of RisperiDONE. Risk C: Monitor therapy

Rivaroxaban: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rivaroxaban. For clarithromycin, refer to more specific clarithromycin-rivaroxaban monograph recommendations. Risk C: Monitor therapy

Roflumilast-Containing Products: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Roflumilast-Containing Products. Risk C: Monitor therapy

RomiDEPsin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of RomiDEPsin. Risk C: Monitor therapy

Ropeginterferon Alfa-2b: Myelosuppressive Agents may enhance the myelosuppressive effect of Ropeginterferon Alfa-2b. Management: Avoid coadministration of ropeginterferon alfa-2b and other myelosuppressive agents. If this combination cannot be avoided, monitor patients for excessive myelosuppressive effects. Risk D: Consider therapy modification

Rubella- or Varicella-Containing Live Vaccines: May enhance the adverse/toxic effect of Immunosuppressants (Miscellaneous Oncologic Agents). Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Rubella- or Varicella-Containing Live Vaccines. Risk X: Avoid combination

Rupatadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rupatadine. Risk X: Avoid combination

Ruxolitinib (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ruxolitinib (Systemic). Management: This combination should be avoided under some circumstances; dose adjustments may be required in some circumstances and depend on the indication for ruxolitinib. See monograph for details. Risk D: Consider therapy modification

Ruxolitinib (Topical): Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Ruxolitinib (Topical). Risk X: Avoid combination

Ruxolitinib (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ruxolitinib (Topical). Risk X: Avoid combination

Salmeterol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Salmeterol. Risk X: Avoid combination

SAXagliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SAXagliptin. Management: Limit the saxagliptin dose to 2.5 mg daily when combined with strong CYP3A4 inhibitors. When using the saxagliptin combination products saxagliptin/dapagliflozin or saxagliptin/dapagliflozin/metformin, avoid use with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Selpercatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Selpercatinib. Management: Avoid combination if possible. If use is necessary, reduce selpercatinib dose as follows: from 120 mg twice/day to 40 mg twice/day, or from 160 mg twice/day to 80 mg twice/day. Risk D: Consider therapy modification

Selumetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Selumetinib. Management: Avoid concomitant use when possible. If combined, selumetinib dose reductions are recommended and vary based on body surface area and selumetinib dose. For details, see the full drug interaction monograph or selumetinib prescribing information. Risk D: Consider therapy modification

Sertindole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sertindole. Risk X: Avoid combination

Sibutramine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Sibutramine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sibutramine. Risk C: Monitor therapy

Sildenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sildenafil. Management: Use of sildenafil for pulmonary arterial hypertension (PAH) should be avoided with strong CYP3A4 inhibitors. When used for erectile dysfunction, consider using a lower starting dose of 25 mg and monitor patients for sildenafil toxicities. Risk D: Consider therapy modification

Silodosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Silodosin. Risk X: Avoid combination

Simeprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simeprevir. Risk X: Avoid combination

Simvastatin: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Simvastatin. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simvastatin. Risk X: Avoid combination

Sipuleucel-T: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Sipuleucel-T. Management: Consider reducing the dose or discontinuing the use of immunosuppressants prior to initiating sipuleucel-T therapy. Risk D: Consider therapy modification

Sirolimus (Conventional): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sirolimus (Conventional). Management: Avoid concurrent use of sirolimus with strong CYP3A4 inhibitors when possible and alternative agents with lesser interaction potential with sirolimus should be considered. Concomitant use of sirolimus and voriconazole or posaconazole is contraindicated. Risk D: Consider therapy modification

Sirolimus (Protein Bound): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sirolimus (Protein Bound). Risk X: Avoid combination

Sirolimus (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sirolimus (Topical). Risk C: Monitor therapy

Solifenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Solifenacin. Management: Limit adult solifenacin doses to 5 mg daily and limit doses in pediatric patients to the recommended weight-based starting dose (and do not increase the dose) when combined with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Sonidegib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sonidegib. Risk X: Avoid combination

Sphingosine 1-Phosphate (S1P) Receptor Modulator: May enhance the immunosuppressive effect of Immunosuppressants (Miscellaneous Oncologic Agents). Risk C: Monitor therapy

SUFentanil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SUFentanil. Management: If a strong CYP3A4 inhibitor is initiated in a patient on sufentanil, consider a sufentanil dose reduction and monitor for increased sufentanil effects and toxicities (eg, respiratory depression). Risk D: Consider therapy modification

SUNItinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SUNItinib. Management: Avoid when possible. If combined, decrease sunitinib dose to a minimum of 37.5 mg daily when treating GIST or RCC. Decrease sunitinib dose to a minimum of 25 mg daily when treating PNET. Monitor patients for both reduced efficacy and increased toxicities. Risk D: Consider therapy modification

Suvorexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Suvorexant. Risk X: Avoid combination

Tacrolimus (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tacrolimus (Systemic). Management: Reduce tacrolimus dose to one-third of the original dose if starting posaconazole or voriconazole. Coadministration with nelfinavir is not generally recommended. Tacrolimus dose reductions or prolongation of dosing interval will likely be required. Risk D: Consider therapy modification

Tacrolimus (Topical): Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Tacrolimus (Topical). Risk X: Avoid combination

Tadalafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tadalafil. Management: Avoid this combination in patients taking tadalafil for pulmonary arterial hypertension. In patients taking tadalafil for ED or BPH, max tadalafil dose is 2.5 mg if taking daily or 10 mg no more frequently than every 72 hours if used as needed. Risk D: Consider therapy modification

Talimogene Laherparepvec: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Talimogene Laherparepvec. Specifically, the risk of infection from the live, attenuated herpes simplex virus contained in talimogene laherparepvec may be increased. Risk X: Avoid combination

Tamsulosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tamsulosin. Risk X: Avoid combination

Tasimelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tasimelteon. Risk C: Monitor therapy

Tazemetostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tazemetostat. Risk X: Avoid combination

Temsirolimus: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Temsirolimus. Specifically, concentrations of sirolimus may be increased. Management: Avoid concomitant use of temsirolimus and strong CYP3A4 inhibitors. If coadministration is unavoidable, decrease temsirolimus dose to 12.5 mg per week. Resume previous temsirolimus dose 1 week after discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Terfenadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Terfenadine. Risk X: Avoid combination

Tertomotide: Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Tertomotide. Risk X: Avoid combination

Tetrahydrocannabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tetrahydrocannabinol. Risk C: Monitor therapy

Tetrahydrocannabinol and Cannabidiol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tetrahydrocannabinol and Cannabidiol. Risk C: Monitor therapy

Tezacaftor and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tezacaftor and Ivacaftor. Management: If combined with strong CYP3A4 inhibitors, tezacaftor/ivacaftor should be administered in the morning, twice a week, approximately 3 to 4 days apart. Tezacaftor/ivacaftor dose depends on age and weight; see full Lexi-Interact monograph for details. Risk D: Consider therapy modification

Thiotepa: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Thiotepa. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Thiotepa. Management: Avoid coadministration of thiotepa and strong CYP3A4 inhibitors. If concomitant use cannot be avoided, monitor for thiotepa adverse effects and decreased efficacy. Risk D: Consider therapy modification

Ticagrelor: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ticagrelor. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ticagrelor. Risk X: Avoid combination

Tisotumab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tisotumab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Risk C: Monitor therapy

Tofacitinib: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Tofacitinib. Risk X: Avoid combination

Tolterodine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolterodine. Management: The maximum recommended dose of tolterodine is 2 mg per day (1 mg twice daily for immediate-release tablets or 2 mg daily for extended-release capsules) when used together with a strong CYP3A4 inhibitor. Risk D: Consider therapy modification

Tolvaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolvaptan. Risk X: Avoid combination

Toremifene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Toremifene. Management: Use of toremifene with strong CYP3A4 inhibitors should be avoided if possible. If coadministration is necessary, monitor for increased toremifene toxicities, including QTc interval prolongation. Risk D: Consider therapy modification

Trabectedin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Trabectedin. Risk X: Avoid combination

TraMADol: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of TraMADol. CYP3A4 Inhibitors (Strong) may increase the serum concentration of TraMADol. Risk C: Monitor therapy

TraZODone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of TraZODone. Management: Consider the use of a lower trazodone dose and monitor for increased trazodone effects (eg, sedation, QTc prolongation) if combined with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Tretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tretinoin (Systemic). Risk C: Monitor therapy

Triamcinolone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triamcinolone (Nasal). Risk C: Monitor therapy

Triamcinolone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triamcinolone (Ophthalmic). Risk C: Monitor therapy

Triamcinolone (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triamcinolone (Systemic). Management: Consider alternatives to this combination when possible. If combined, monitor for increased corticosteroid adverse effects during coadministration of triamcinolone and strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Triamcinolone (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triamcinolone (Topical). Risk C: Monitor therapy

Triazolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triazolam. Risk X: Avoid combination

Typhoid Vaccine: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Typhoid Vaccine. Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Typhoid Vaccine. Risk X: Avoid combination

Ubrogepant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ubrogepant. Risk X: Avoid combination

Udenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Udenafil. Risk X: Avoid combination

Ulipristal: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ulipristal. Risk C: Monitor therapy

Upadacitinib: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the immunosuppressive effect of Upadacitinib. Risk X: Avoid combination

Vaccines (Inactivated/Non-Replicating): Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Vaccines (Inactivated/Non-Replicating). Management: Give inactivated vaccines at least 2 weeks prior to initiation of immunosuppressants when possible. Patients vaccinated less than 14 days before initiating or during therapy should be revaccinated at least 3 after therapy is complete. Risk D: Consider therapy modification

Vaccines (Live): Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Vaccines (Live). Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Vaccines (Live). Risk X: Avoid combination

Valbenazine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Valbenazine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Valbenazine. Management: Reduce the valbenazine dose to 40 mg daily when combined with strong CYP3A4 inhibitors. Risk D: Consider therapy modification

Vardenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vardenafil. Management: Limit Levitra (vardenafil) dose to a single 2.5 mg dose within a 24-hour period if combined with strong CYP3A4 inhibitors. Avoid concomitant use of Staxyn (vardenafil) and strong CYP3A4 inhibitors. Combined use is contraindicated outside of the US. Risk D: Consider therapy modification

Vemurafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vemurafenib. Management: Avoid concurrent use of vemurafenib with strong CYP3A4 inhibitors when possible. If concomitant use is unavoidable, consider a vemurafenib dose reduction if clinically indicated. Risk D: Consider therapy modification

Venetoclax: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Venetoclax. Management: Coadministration is contraindicated during venetoclax initiation and ramp-up in CLL/SLL patients. Reduced venetoclax doses are required during ramp-up for patients with AML, and all maintenance therapy. See full Lexi Interact monograph for details. Risk D: Consider therapy modification

Verapamil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Verapamil. Risk C: Monitor therapy

Vilanterol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vilanterol. Risk C: Monitor therapy

Vilazodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vilazodone. Management: Limit the maximum vilazodone dose to 20 mg daily in patients receiving strong CYP3A4 inhibitors. The original vilazodone dose can be resumed following discontinuation of the strong CYP3A4 inhibitor. Risk D: Consider therapy modification

VinBLAStine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinBLAStine. Risk C: Monitor therapy

VinCRIStine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinCRIStine. Management: Seek alternatives to this combination when possible. If combined, monitor closely for vincristine toxicities (eg, neurotoxicity, gastrointestinal toxicity, myelosuppression). Risk D: Consider therapy modification

VinCRIStine (Liposomal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinCRIStine (Liposomal). Risk X: Avoid combination

Vindesine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vindesine. Risk C: Monitor therapy

Vinflunine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Vinflunine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinflunine. Risk X: Avoid combination

Vinorelbine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinorelbine. Risk C: Monitor therapy

Voclosporin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Voclosporin. Risk X: Avoid combination

Vorapaxar: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vorapaxar. Risk X: Avoid combination

Yellow Fever Vaccine: Immunosuppressants (Miscellaneous Oncologic Agents) may enhance the adverse/toxic effect of Yellow Fever Vaccine. Specifically, the risk of vaccine-associated infection may be increased. Immunosuppressants (Miscellaneous Oncologic Agents) may diminish the therapeutic effect of Yellow Fever Vaccine. Risk X: Avoid combination

Zanubrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zanubrutinib. Management: Decrease the zanubrutinib dose to 80 mg once daily during coadministration with a strong CYP3A4 inhibitor. Further dose adjustments may be required for zanubrutinib toxicities, refer to prescribing information for details. Risk D: Consider therapy modification

Ziprasidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ziprasidone. Risk C: Monitor therapy

Zolpidem: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zolpidem. Risk C: Monitor therapy

Zopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zopiclone. Management: If coadministered with strong CYP3A4 inhibitors, initiate zopiclone at 3.75 mg in adults, with a maximum dose of 5 mg. Monitor for zopiclone toxicity (eg, drowsiness, confusion, lethargy, ataxia, respiratory depression). Risk D: Consider therapy modification

Reproductive Considerations

Verify pregnancy status prior to treatment initiation in patients who could become pregnant. Patients who could become pregnant should use effective contraception during therapy and for 1 month after the final idelalisib dose. Patients with partners who could become pregnant should use effective contraception during therapy and for 3 months after the final idelalisib dose.

Pregnancy Considerations

Based on findings in animal reproduction studies and the mechanism of action, idelalisib may cause fetal harm if administered during pregnancy.

Breastfeeding Considerations

It is not known if idelalisib is present in breast milk. Due to the potential for serious adverse reactions in the breastfed infant, the manufacturer recommends not breastfeeding during treatment and for 1 month after the last idelalisib dose.

Monitoring Parameters

Complete blood counts with differential at least every 2 weeks for the first 6 months, and at least weekly in patients with neutropenia (ANC <1,000/mm3 ), or as clinically necessary; liver function tests at baseline and every 2 weeks for the first 3 months, every 4 weeks for the next 3 months, then every 1 to 3 months thereafter, or as clinically necessary; increase monitoring to weekly if ALT or AST >3 times ULN until resolved. Evaluate pregnancy status (prior to treatment initiation in patients who could become pregnant). Monitor for infections (including sepsis and pneumonia). Monitor for symptoms or laboratory evidence of opportunistic infections, including Pneumocystis jirovecii pneumonia, cytomegalovirus, herpes virus infections, and Epstein-Barr virus (Hallek 2018). Monitor for signs/symptoms of diarrhea/colitis, intestinal perforation (new or worsening abdominal pain, chills, fever, nausea, or vomiting), pneumonitis (monitor for pulmonary symptoms and bilateral interstitial infiltrates), dermatologic toxicity, and hypersensitivity reactions. Monitor adherence.

The American Society of Clinical Oncology hepatitis B virus (HBV) screening and management provisional clinical opinion (ASCO [Hwang 2020]) recommends HBV screening with hepatitis B surface antigen, hepatitis B core antibody, total Ig or IgG, and antibody to hepatitis B surface antigen prior to beginning (or at the beginning of) systemic anticancer therapy; do not delay treatment for screening/results. Detection of chronic or past HBV infection requires a risk assessment to determine antiviral prophylaxis requirements, monitoring, and follow-up.

Mechanism of Action

Idelalisib is a potent small molecule inhibitor of the delta isoform of phosphatidylinositol 3-kinase (PI3Kδ), which is highly expressed in malignant lymphoid B-cells. PI3Kδ inhibition results in apoptosis of malignant tumor cells. In addition, idelalisib inhibits several signaling pathways, including B-cell receptor, CXCR4 and CXCR5 signaling which may play important roles in CLL pathophysiology (Furman 2014). In lymphoma cells, idelalisib treatment inhibited chemotaxis and adhesion, and reduced cell viability.

Pharmacokinetics

Distribution: 23 L.

Protein binding: ≥84%.

Metabolism: Hepatic; primarily via aldehyde oxidase and CYP3A (to major metabolite GS-563117); minor metabolism via UGT1A4.

Half-life elimination: 8.2 hours.

Time to peak: Median: 1.5 hours.

Excretion: Feces (78%); urine (14%).

Clearance: 14.9 L/hour.

Pharmacokinetics: Additional Considerations

Hepatic function impairment: The idelalisib mean AUC increased up to 1.7-fold in patients with ALT or AST or bilirubin ≥ULN as compared with patients with normal hepatic function.

Pricing: US

Tablets (Zydelig Oral)

100 mg (per each): $248.60

150 mg (per each): $248.60

Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.

Brand Names: International
  • Zydelig (AT, AU, BB, BE, CH, CY, CZ, DE, DK, EE, ES, FR, GB, HR, IE, IS, LT, LU, MT, NL, NO, PL, RO, SE, SI, SK)


For country code abbreviations (show table)
  1. Furman RR, Sharman JP, Coutre Se, et al. Idelalisib and rituximab in relapsed chronic lymphocytic leukemia. N Engl J Med. 2014; 370(11):997-1007. [PubMed 24450857]
  2. Hallek M, Cheson BD, Catovsky D, et al. iwCLL guidelines for diagnosis, indications for treatment, response assessment, and supportive management of CLL. Blood. 2018;131(25):2745-2760. doi:10.1182/blood-2017-09-806398 [PubMed 29540348]
  3. Hwang JP, Feld JJ, Hammond SP, et al. Hepatitis B virus screening and management for patients with cancer prior to therapy: ASCO provisional clinical opinion update. J Clin Oncol. 2020;38(31):3698-3715. doi:10.1200/JCO.20.01757 [PubMed 32716741]
  4. Jin F, Robeson M, Zhou H, et al. The pharmacokinetics and safety of idelalisib in subjects with moderate or severe hepatic impairment. J Clin Pharmacol. 2015a;55(8):944-952. [PubMed 25821156]
  5. Jin F, Robeson M, Zhou H, et al. The pharmacokinetics and safety of idelalisib in subjects with severe renal impairment. Cancer Chemother Pharmacol. 2015b;76(6):1133-1141. [PubMed 26526983]
  6. Raisch DW, Rafi JA, Chen C, Bennett CL. Detection of cases of progressive multifocal leukoencephalopathy associated with new biologicals and targeted cancer therapies from the FDA's adverse event reporting system. Expert Opin Drug Saf. 2016;15(8):1003-1011. [PubMed 27268272]
  7. Sharman JP, Coutre SE, Furman RR, et al. Final results of a randomized, phase III study of rituximab with or without idelalisib followed by open-label idelalisib in patients with relapsed chronic lymphocytic leukemia. J Clin Oncol. 2019;37(16):1391-1402. doi: 10.1200/JCO.18.01460. [PubMed 30995176]
  8. Zydelig (idelalisib) [prescribing information]. Foster City, CA: Gilead Sciences Inc; February 2022.
  9. Zydelig (idelalisib) [product monograph]. Mississauga, Ontario, Canada: Gilead Sciences Canada, Inc; August 2020.
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