HIV-1 infection, treatment: Not approved for use; a reliable, effective dose has not been established; a high interpatient variability in serum drug concentrations occurs; nelfinavir dosing is problematic in neonates, since the drug is best absorbed when taken with a high-fat meal (HHS [pediatric] 2016; Hirt 2006).
HIV-1 infection, treatment: Use in combination with other antiretroviral agents: Oral:
Infants and Children <2 years: Not approved for use; a reliable, effective dose has not been established; high interpatient variability in serum drug concentrations occurs; nelfinavir dosing is problematic in young infants, since the drug is best absorbed when taken with a high-fat meal (HHS [pediatric] 2016; Hirt 2006).
Children ≥2 years: Note: Pediatric guidelines recommend twice-daily dosing (HHS [pediatric] 2016).
Weight-directed dosing: 45 to 55 mg/kg/dose (maximum dose: 1,250 mg/dose) twice daily or 25 to 35 mg/kg/dose (maximum dose: 750 mg/dose) 3 times daily; daily doses >2,500 mg/day have not been studied in children. Due to the high variability of nelfinavir plasma concentrations in children, dosage adjustment utilizing measurement of plasma concentrations and pharmacokinetics may be beneficial (Crommentuyn 2006; HHS [pediatric] 2016; Fletcher 2008).
Fixed dosing: Oral tablets (250 mg):
10 to <13 kg: 500 mg (2 tablets) twice daily or 250 mg (1 tablet) three times daily
13 to <19 kg: 750 mg (3 tablets) twice daily or 500 mg (2 tablets) three times daily
19 to <21 kg: 1,000 mg (4 tablets) twice daily or 500 mg (2 tablets) three times daily
≥21 kg: 1,000 to 1,250 mg (4 to 5 tablets) twice daily or 750 mg (3 tablets) three times daily
Adolescents: 1,250 mg twice daily or 750 mg three times daily. Note: Some adolescent patients require doses higher than adults to achieve similar nelfinavir AUCs; consider the use of serum drug concentrations to guide optimal dosing (HHS [pediatric] 2016).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no adjustments provided in the manufacturer's labeling (has not been studied). Guidelines suggest that no adjustment is necessary (HHS [adult] 2015). Since <2% of the drug is eliminated in the urine, renal impairment should have minimal effect on nelfinavir elimination
Children ≥2 years and Adolescents:
Mild hepatic impairment (Child-Pugh Class A): Use with caution; no dosage adjustment is necessary.
Moderate to severe hepatic impairment (Child-Pugh Class B or C): Use not recommended.
(For additional information see "Nelfinavir: Drug information")
HIV-1 infection, treatment: Oral: 750 mg 3 times daily or 1,250 mg twice daily with meals in combination with other antiretroviral therapies. Note: In the United States, nelfinavir is no longer recommended for use in the treatment of HIV (HHS [adult 2019]).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied). However, since <2% excreted in urine, a dosage reduction would not be expected.
Mild impairment (Child-Pugh class A): No dosage adjustment necessary.
Moderate to severe impairment (Child-Pugh class B or C): Use not recommended.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Viracept: 250 mg, 625 mg
No
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Powder, Oral:
Viracept: 50 mg/g ([DSC])
Tablet, Oral:
Viracept: 250 mg [DSC] [contains fd&c blue #2 (indigotine)]
Viracept: 625 mg [DSC]
Oral: Administer with food to enhance bioavailability and decrease kinetic variability.
Tablets can be readily dissolved in water and consumed; consume immediately; rinse glass with water and swallow to make sure total dose is consumed; tablets can also be crushed and administered with pudding or other nonacidic food. If coadministered with didanosine, nelfinavir should be administered 2 hours before or 1 hour after didanosine.
Tablets: Administer with a meal. If unable to swallow tablets, may dissolve tablets in a small amount of water; mix cloudy liquid well and consume immediately. Rinse glass with water and administer rinse to ensure receiving full dose. Alternatively, the tablets may be crushed and mixed with a small amount of food; entire contents should be consumed immediately. Avoid mixing with acidic foods or juices as combination may result in a bitter taste (Viracept Canadian product monograph 2016).
Store at room temperature of 15°C to 30°C (59°F to 86°F).
Treatment of HIV-1 infection in combination with other antiretroviral agents (FDA approved in ages ≥2 years and adults). Note: HIV regimens consisting of three antiretroviral agents are strongly recommended.
Nelfinavir may be confused with nevirapine
Viracept may be confused with Viramune, Viramune XR
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reaction incidence reported with combination therapy in adolescents and adults unless otherwise indicated.
>10%: Gastrointestinal: Diarrhea (children: 39% to 47%; adolescents and adults: 14% to 20%)
1% to 10%:
Dermatologic: Dermatitis (<2%), diaphoresis (<2%), folliculitis (<2%), fungal dermatitis (<2%), maculopapular rash (<2%), pruritus (<2%), skin rash (1% to 3%), urticaria (<2%)
Endocrine & metabolic: Dehydration (<2%), hyperglycemia (<2%), hyperlipidemia (<2%), hyperuricemia (<2%), hypoglycemia (<2%), increased lactate dehydrogenase (<2%), redistribution of body fat (<2%)
Gastrointestinal: Abdominal pain (<2%), anorexia (<2%), dyspepsia (<2%), epigastric pain (<2%), flatulence (1% to 5%), gastrointestinal hemorrhage (<2%), increased amylase (<2%), nausea (3% to 7%), oral mucosa ulcer (<2%), pancreatitis (<2%), vomiting (<2%)
Genitourinary: Sexual disorder (<2%), urine abnormality (<2%)
Hematologic & oncologic: Anemia (<2%), decreased neutrophils (1% to 5%), leukopenia (<2%), lymphocytopenia (1% to 6%), thrombocytopenia (<2%)
Hepatic: Hepatitis (<2%), increased gamma-glutamyl transferase (<2%), increased serum alanine aminotransferase (<2%), increased serum alkaline phosphatase (<2%), increased serum aspartate aminotransferase (<2%)
Hypersensitivity: Hypersensitivity reaction (<2%)
Nervous system: Anxiety (<2%), asthenia (<2%), depression (<2%), dizziness (<2%), drowsiness (<2%), emotional lability (<2%), headache (<2%), insomnia (<2%), malaise (<2%), migraine (<2%), myasthenia (<2%), pain (<2%), paresthesia (<2%), seizure (<2%), sleep disorder (<2%), suicidal ideation (<2%)
Neuromuscular & skeletal: Arthralgia (<2%), arthritis (<2%), back pain (<2%), hyperkinetic muscle activity (<2%), increased creatine phosphokinase in blood specimen (<2%), lipotrophy (<2%), muscle cramps (<2%), myalgia (<2%), myopathy (<2%)
Ophthalmic: Acute iritis (<2%), eye disease (<2%)
Renal: Nephrolithiasis (<2%)
Respiratory: Dyspnea (<2%), pharyngitis (<2%), rhinitis (<2%), sinusitis (<2%)
Miscellaneous: Fever (<2%)
Postmarketing:
Cardiovascular: Bradycardia (Landovitz 1999), prolonged QT interval on ECG (Anson 2005), torsades de pointes (Anson 2005)
Endocrine & metabolic: Metabolic acidosis
Hepatic: Hyperbilirubinemia (Hill 2001), jaundice (Hill 2001)
Immunologic: Immune reconstitution syndrome (Sharland 1998)
Coadministration with drugs that are highly dependent on CYP3A for clearance and for which elevated or reduced plasma concentrations are associated with serious and/or life-threatening events or lead to reduced efficacy of nelfinavir (eg, alfuzosin, amiodarone, cisapride, ergot derivatives [eg, dihydroergotamine, ergonovine, ergotamine, methylergonovine], lovastatin, lurasidone, oral midazolam, pimozide, quinidine, rifampin, sildenafil [when used for the treatment of pulmonary hypertension], simvastatin, St John's wort, triazolam).
Canadian labeling: Additional contraindications (not in US labeling): Clinically significant hypersensitivity to nelfinavir or any component of the formulation; coadministration with midazolam (regardless of dosage form)
Concerns related to adverse effects:
• Diarrhea: Diarrhea occurs frequently with use, particularly in children; a secretory diarrhea mediated via a calcium-dependent process may also occur; calcium carbonate administered at the same time as nelfinavir has been used to treat this adverse effect in adults without affecting plasma concentrations of nelfinavir or its major metabolite.
• Fat redistribution: May cause redistribution of fat (eg, buffalo hump, peripheral wasting with increased abdominal girth, cushingoid appearance).
• Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves disease, polymyositis, Guillain-Barré syndrome) later in therapy; further evaluation and treatment may be required.
Disease-related concerns:
• Diabetes: Changes in glucose tolerance, hyperglycemia, exacerbation of diabetes, DKA, and new-onset diabetes mellitus have been reported in patients receiving protease inhibitors.
• Hemophilia A or B: Use with caution in patients with hemophilia A or B; increased bleeding during protease inhibitor therapy has been reported.
• Hepatic impairment: May cause hepatitis and/or exacerbate preexisting hepatic dysfunction; use with caution in patients with underlying hepatic disease, such as hepatitis B or C or cirrhosis; use not recommended with moderate-to-severe impairment.
Lipodystrophy was observed in 28% of children after a median of 49 months of receiving a nelfinavir-containing antiretroviral regimen (Scherpbier 2006).
May cause diarrhea (children: 39% to 47%; adults: 14% to 20%); a secretory diarrhea mediated via a calcium-dependent process may also occur; calcium carbonate administered at the same time as nelfinavir has been used to treat this adverse effect in adults without affecting plasma concentrations of nelfinavir or its major metabolite.
Substrate of CYP2C19 (major), CYP2C9 (minor), CYP2D6 (minor), CYP3A4 (major), P-glycoprotein/ABCB1 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits CYP3A4 (strong); Induces CYP1A2 (weak), CYP2B6 (weak), CYP2C9 (weak)
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.
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
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
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
Afatinib: Nelfinavir may increase the serum concentration of Afatinib. Management: Monitor for signs and symptoms of afatinib toxicity when these agents are combined. Consider administering nelfinavir simultaneously with, or after, the dose of afatinib. If the combination is not tolerated, consider reducing the afatinib dose by 10 mg. Risk C: Monitor therapy
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: Nelfinavir may increase the serum concentration of Amiodarone. Risk X: Avoid combination
AmLODIPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of AmLODIPine. Risk C: Monitor therapy
Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Risk C: Monitor therapy
Apalutamide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Apalutamide. 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: Protease Inhibitors may increase the serum concentration of Artemether and Lumefantrine. Specifically, the concentrations of lumefantrine may be increased. Protease Inhibitors may decrease the serum concentration of Artemether and Lumefantrine. Specifically, concentrations of artemether and dihydroartemisinin (DHA), the active metabolite of artemether, may be decreased. 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
Atazanavir: May increase the serum concentration of Protease Inhibitors. 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: Nelfinavir may increase the serum concentration of Atorvastatin. Management: Use the lowest atorvastatin dose necessary in patients taking nelfinavir, and do not exceed atorvastatin 40 mg daily. Monitor patients for signs and symptoms of myopathy at initiation of therapy and with any dose increase. Risk D: Consider therapy modification
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
Azithromycin (Systemic): Nelfinavir may increase the serum concentration of Azithromycin (Systemic). Risk C: Monitor therapy
Barnidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Barnidipine. 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
Betibeglogene Autotemcel: Antiretroviral Agents may diminish the therapeutic effect of Betibeglogene Autotemcel. Risk X: Avoid combination
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: Protease Inhibitors may increase the serum concentration of Bosentan. Management: Dose adjustment of bosentan and increased monitoring for bosentan toxicities is necessary when these agents are combined. See full drug interaction monograph for details. Risk D: Consider therapy modification
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
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
BuPROPion: CYP2B6 Inducers (Weak) may decrease the serum concentration of BuPROPion. 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
CarBAMazepine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of CarBAMazepine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of CarBAMazepine. 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
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
Clarithromycin: Protease Inhibitors may decrease serum concentrations of the active metabolite(s) of Clarithromycin. Protease Inhibitors may increase the serum concentration of Clarithromycin. Management: Do not exceed clarithromycin doses greater than 1,000 mg/day in patients taking protease inhibitors. If CrCL is 30 to 60 mL/min, reduced clarithromycin dose 50%. If CrCL is less than 30 mL/min, reduced clarithromycin dose 75%. Risk D: Consider therapy modification
Clindamycin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Clindamycin (Systemic). Risk C: Monitor therapy
ClonazePAM: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ClonazePAM. Risk C: Monitor therapy
CloZAPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of CloZAPine. Risk C: Monitor therapy
CloZAPine: CYP1A2 Inducers (Weak) may decrease the serum concentration of CloZAPine. Risk C: Monitor therapy
Cobicistat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cobicistat. Risk C: Monitor therapy
Cobimetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cobimetinib. Risk X: Avoid combination
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
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
Cyclophosphamide: Protease Inhibitors may enhance the adverse/toxic effect of Cyclophosphamide. Specifically, the incidences of neutropenia, infection, and mucositis may be increased. Protease Inhibitors may increase the serum concentration of Cyclophosphamide. Risk C: Monitor therapy
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
CYP2C19 Inducers (Moderate): May decrease the serum concentration of Nelfinavir. Risk C: Monitor therapy
CYP2C19 Inhibitors (Strong): May increase the serum concentration of Nelfinavir. Risk C: Monitor therapy
CYP3A4 Inducers (Moderate): May decrease the serum concentration of Nelfinavir. Risk C: Monitor therapy
CYP3A4 Inducers (Strong): May decrease the serum concentration of Nelfinavir. Risk C: Monitor therapy
CYP3A4 Inhibitors (Strong): May increase the serum concentration of Nelfinavir. Risk C: Monitor therapy
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
Darunavir: Protease Inhibitors may decrease the serum concentration of Darunavir. Protease Inhibitors may increase the serum concentration of Darunavir. Risk X: Avoid combination
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
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
Delavirdine: Nelfinavir may decrease the serum concentration of Delavirdine. Delavirdine may increase the serum concentration of Nelfinavir. Management: Consider alternatives to this combination. Safe and effective doses for coadministration have not been determined according to the nelfinavir and delavirdine prescribing information. Risk D: Consider therapy modification
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
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
Elivaldogene Autotemcel: Antiretroviral Agents may diminish the therapeutic effect of Elivaldogene Autotemcel. Management: Avoid use of antiretroviral medications for at least one month, or for the amount of time required for elimination of the retroviral medication, prior to stem cell mobilization and until the all apheresis cycles are finished Risk X: Avoid combination
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
Enzalutamide: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Enzalutamide. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Enzalutamide. Risk C: Monitor therapy
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: Protease Inhibitors may decrease the serum concentration of Estrogen Derivatives. Protease Inhibitors 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
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: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Fexinidazole. Management: Avoid use of fexinidazole and strong CYP3A4 inhibitors when possible. If combined, monitor for reduced fexinidazole efficacy. Risk D: Consider therapy modification
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: Nelfinavir may increase serum concentrations of the active metabolite(s) of Fosamprenavir. Management: Consider alternatives to this combination. Safe and effective doses of fosamprenavir and nelfinavir during coadministration have not been established. Risk D: Consider therapy modification
Fosaprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fosaprepitant. Risk X: Avoid combination
Fosphenytoin-Phenytoin: May decrease the serum concentration of Nelfinavir. Nelfinavir may decrease the serum concentration of Fosphenytoin-Phenytoin. Risk C: Monitor therapy
Fostamatinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fostamatinib. Risk C: Monitor therapy
Galantamine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Galantamine. Risk C: Monitor therapy
Garlic: May decrease the serum concentration of Protease Inhibitors. Risk X: Avoid combination
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: QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of Haloperidol. Risk C: Monitor therapy
Haloperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Haloperidol. Risk C: Monitor therapy
Histamine H2 Receptor Antagonists: May decrease serum concentrations of the active metabolite(s) of Nelfinavir. Histamine H2 Receptor Antagonists may decrease the serum concentration of Nelfinavir. Concentrations of the active M8 metabolite may also be reduced. Risk C: Monitor therapy
Hormonal Contraceptives: Protease Inhibitors may decrease the serum concentration of Hormonal Contraceptives. Specifically, protease inhibitors may decrease concentrations of estrogens. Protease Inhibitors may increase the serum concentration of Hormonal Contraceptives. Specifically, protease inhibitors may increase concentrations of progestins. Management: Use alternative or additional nonhormonal forms of contraception when estrogen-containing hormonal contraceptives are combined with protease inhibitors. Progestin-only contraceptives can be used without back up, but monitor for progestin toxicities. Risk D: Consider therapy modification
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
Idelalisib: 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
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
Indinavir: Nelfinavir may increase the serum concentration of Indinavir. Indinavir may increase the serum concentration of Nelfinavir. Management: Consider alternatives to this combination. Safe and effective doses for coadministration have not been determined according to both the nelfinavir and indinavir prescribing information. Risk D: Consider therapy modification
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
Inhibitors of the Proton Pump (PPIs and PCABs): May decrease serum concentrations of the active metabolite(s) of Nelfinavir. Inhibitors of the Proton Pump (PPIs and PCABs) may decrease the serum concentration of Nelfinavir. Management: Due to potentially significant reductions in nelfinavir exposure, avoid concurrent use of nelfinavir with a PPI or PCAB when possible. If unavoidable, consider PPI or PCAB use for a short duration (less than 30 days) and closely monitor viral load. 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
Itraconazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Itraconazole. Risk C: Monitor therapy
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
Ketoconazole (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ketoconazole (Systemic). 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
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: Nelfinavir may decrease 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
Lopinavir: Nelfinavir may decrease the serum concentration of Lopinavir. Lopinavir may increase the serum concentration of Nelfinavir. Concentrations of the nelfinavir M8 metabolite may also be increased. Management: Avoid once daily use of lopinavir/ritonavir with nelfinavir. Avoid use of this combination in patients less than 6 months of age. Lopinavir/ritonavir dose adjustments are required for patients taking twice daily lopinavir/ritonavir. See full monograph. Risk D: Consider therapy modification
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
Lumacaftor and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lumacaftor and Ivacaftor. Management: When initiating or resuming lumacaftor/ivacaftor after a therapy interruption of 7 days or more, reduce the lumacaftor/ivacaftor dose to 1 tablet daily or 1 packet of oral granules every other day for the first week, and then resume the standard dose. Risk D: Consider therapy modification
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: Nelfinavir may decrease the serum concentration of Methadone. Risk C: Monitor therapy
MethylPREDNISolone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MethylPREDNISolone. Risk C: Monitor therapy
Midazolam: Protease Inhibitors may increase the serum concentration of Midazolam. Management: Oral midazolam is contraindicated with protease inhibitors. Avoid use with nasal midazolam. Consider alternatives to use with other routes of midazolam (IV, IM) when possible. Consider use of lower midazolam doses if combined. Risk X: Avoid combination
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
Neratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Neratinib. Risk X: Avoid combination
Nevirapine: May decrease the serum concentration of Nelfinavir. 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
Nirmatrelvir and Ritonavir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nirmatrelvir and Ritonavir. Risk C: Monitor therapy
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
OLANZapine: CYP1A2 Inducers (Weak) may decrease the serum concentration of OLANZapine. 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
Orlistat: May decrease the serum concentration of Antiretroviral Agents. Risk C: Monitor therapy
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
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: CYP3A4 Inhibitors (Strong) may decrease the metabolism of Pimecrolimus. Risk C: Monitor therapy
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
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
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
Pravastatin: Nelfinavir may decrease the serum concentration of Pravastatin. Risk C: Monitor therapy
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
Propafenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Propafenone. Risk C: Monitor therapy
QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. 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: Nelfinavir may increase the serum concentration of QuiNIDine. Risk X: Avoid combination
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
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: Nelfinavir may increase serum concentrations of the active metabolite(s) of Rifabutin. Rifabutin may decrease the serum concentration of Nelfinavir. Nelfinavir may increase the serum concentration of Rifabutin. Management: Decrease the usual rifabutin dose by at least 50% when used with nelfinavir. Additionally, the preferred dose of nelfinavir when used in combination with rifabutin is 1250 mg twice daily. Rifabutin doses may also need to be adjusted. Risk D: Consider therapy modification
RifAMPin: May decrease the serum concentration of Nelfinavir. Risk X: Avoid combination
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
Ritonavir: May increase the serum concentration of Nelfinavir. Management: Consider alternatives to this combination. Safe and effective doses for coadministration have not been determined according to the nelfinavir prescribing information. Risk D: Consider therapy modification
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
Rosuvastatin: Protease Inhibitors may increase the serum concentration of Rosuvastatin. Risk C: Monitor therapy
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): 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
Saquinavir: May increase the serum concentration of Nelfinavir. Nelfinavir may increase the serum concentration of Saquinavir. 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: Protease Inhibitors may increase the serum concentration of Sildenafil. Management: Use of protease inhibitors and sildenafil for the treatment of PAH is contraindicated. If using sildenafil for the treatment of erectile dysfunction, limit the sildenafil dose to 25 mg and do not use more frequently than every 48 hours. 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
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
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): Nelfinavir may increase the serum concentration of Tacrolimus (Systemic). Risk X: Avoid combination
Tacrolimus (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tacrolimus (Topical). Risk C: Monitor therapy
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
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
Telithromycin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Telithromycin. Risk C: Monitor therapy
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
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
Tipranavir: Protease Inhibitors may increase the serum concentration of Tipranavir. Tipranavir may decrease the serum concentration of Protease Inhibitors. 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: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tofacitinib. Management: Tofacitinib dose reductions are recommended when combined with strong CYP3A4 inhibitors. Recommended dose adjustments vary by tofacitinib formulation and therapeutic indication. See full Lexi Interact monograph for details. Risk D: Consider therapy modification
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
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: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Upadacitinib. Management: For ulcerative colitis use upadacitinib 30 mg/day for 8 weeks for induction, then 15 mg/day for maintenance. For rheumatoid arthritis, psoriatic arthritis, or atopic dermatitis use upadacitinib 15 mg/day. Monitor for upadacitinib toxicities. Risk D: Consider therapy modification
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
Valproate Products: Protease Inhibitors may decrease the serum concentration of Valproate Products. Risk C: Monitor therapy
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
Vitamin K Antagonists (eg, warfarin): CYP2C9 Inducers (Weak) may decrease the serum concentration of Vitamin K Antagonists. 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
Voriconazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Voriconazole. Risk C: Monitor therapy
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
Zidovudine: Nelfinavir may decrease the serum concentration of Zidovudine. Risk C: Monitor therapy
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
Nelfinavir taken with food increases plasma concentration time curve (AUC) by two- to threefold. Management: Administer with a meal. Do not administer with acidic food or juice (orange juice, apple juice, or applesauce) since the combination may have a bitter taste.
Should be taken as scheduled with a meal.
Based on the Health and Humans Services (HHS) perinatal HIV guidelines, nelfinavir is not one of the recommended antiretroviral agents for use in patients with HIV infection who are trying to conceive.
Patients with HIV infection not planning to become pregnant may use any available type of contraception, considering possible drug interactions and contraindications of the specific method. Consult the drug interactions database for more detailed information specific to use of nelfinavir and specific contraceptives.
Viral suppression sustained below the limits of detection with antiretroviral therapy (ART) and modification of therapy (if needed) is recommended in all patients with HIV infection who are planning a pregnancy. Optimization of the health of the person who will become pregnant and a discussion of the potential risks and benefits of ART during pregnancy is also recommended prior to conception. In most cases, recommendations from the HHS perinatal HIV guidelines (based on data obtained from cisgender women) can be applied to transgender and gender diverse people assigned female sex at birth.
Health care providers caring for couples planning a pregnancy when one or both partners are diagnosed with HIV infection may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2021).
Nelfinavir crosses the human placenta.
Outcome information specific to nelfinavir use in pregnancy is no longer being reviewed and updated in the Health and Humans Services (HHS) perinatal guidelines. The HHS perinatal HIV guidelines do not recommend nelfinavir for use during pregnancy and patients who are pregnant should be changed to a preferred or alternative therapy.
Maternal antiretroviral therapy (ART) may be associated with adverse pregnancy outcomes including preterm delivery, stillbirth, low birth weight, and small for gestational age infants. Actual risks may be influenced by maternal factors, such as disease severity, gestational age at initiation of therapy, and specific ART regimen; therefore, close fetal monitoring is recommended. Because there is clear benefit to appropriate treatment, maternal ART should not be withheld due to concerns for adverse neonatal outcomes. Long-term follow-up is recommended for all infants exposed to antiretroviral medications; children not diagnosed with HIV infection but who were exposed to ART in utero or as a neonate and develop significant organ system abnormalities of unknown etiology (particularly of the CNS or heart) should be evaluated for potential metabolic dysfunction. The risk of hepatic dysfunction and gestational diabetes may be increased in pregnant patients taking protease inhibitors. Consider performing the standard glucose screening test earlier in pregnancy in patients who initiated protease inhibitor therapy prior to conception.
ART is recommended for all pregnant people with HIV infection to maximize their health, maintain the viral load below the limit of detection, and reduce the risk of perinatal transmission. Therapy should be individualized following a discussion of the potential risks and benefits of treatment during pregnancy. Patients on fully suppressive regimens prior to pregnancy generally may continue the same regimen considering known pregnancy outcomes and pharmacokinetic data. Monitoring of patients who are pregnant is more frequent than in patients who are not pregnant. ART initiated during pregnancy can be modified after delivery. In most cases, recommendations from the HHS perinatal HIV guidelines (based on data obtained from cisgender women) can be applied to transgender and gender diverse people assigned female sex at birth.
Data collection to monitor pregnancy and infant outcomes following exposure to ART is ongoing. Health care providers are encouraged to enroll patients who are pregnant exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263 or https://www.APRegistry.com).
Health care providers caring for pregnant patients with HIV infection and their infants may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2021).
Note: The absolute CD4 cell count is currently recommended to monitor immune status in children of all ages; CD4 percentage can be used as an alternative in children <5 years of age. This recommendation is based on the use of absolute CD4 cell counts in the current pediatric HIV infection stage classification and as thresholds for urgency of initiation of antiretroviral treatment (HHS [pediatric] 2017).
Prior to initiation of therapy: Genotypic resistance testing, CD4 and viral load (every 3 to 4 months), CBC with differential, LFTs, BUN, creatinine, electrolytes, glucose, urinalysis (every 6 to 12 months), and assessment of readiness for adherence with medication regimen. At initiation and with any change in treatment regimen: CBC with differential, electrolytes, calcium, phosphate, glucose, LFTs, bilirubin, urinalysis (at initiation), BUN, creatinine, albumin, total protein, lipid panel (at initiation), CD4, and viral load. After 1 to 2 weeks of therapy: Signs of medication toxicity and adherence. After 2 to 4 weeks of therapy: CBC with differential, viral load, signs of medication toxicity, and adherence; then every 3 to 4 months: CBC with differential, electrolytes, glucose, LFTs, bilirubin, BUN, creatinine, CD4, viral load, signs of medication toxicity, and adherence. Every 6 to 12 months: Lipid panel and urinalysis. CD4 monitoring frequency may be decreased to every 6 to 12 months in children who are adherent to therapy if the value is well above the threshold for opportunistic infections, viral suppression is sustained, and the clinical status is stable for more than 2 to 3 years. In patients with known or suspected complex drug resistance patterns, phenotypic resistance testing (usually in addition to genotypic resistance testing) should be performed (HHS [pediatric] 2017). Monitor for growth and development, signs of HIV-specific physical conditions, HIV disease progression, opportunistic infections.
Plasma trough concentration: ≥800 ng/mL (measurable active (M8) metabolite) (HHS [pediatric] 2016)
Binds to the site of HIV-1 protease activity and inhibits cleavage of viral Gag-Pol polyprotein precursors into individual functional proteins required for infectious HIV. This results in the formation of immature, noninfectious viral particles.
Absorption: AUC is two- to threefold higher under fed conditions versus fasting; AUC is highly variable in pediatric patients due to increased clearance, problems with compliance, and inconsistent food intake with dosing.
Distribution: Vd: 2 to 7 L/kg
Protein binding: >98%
Metabolism: Hepatic via CYP2C19 and 3A4; major metabolite has activity comparable to parent drug
Bioavailability: 20% to 80%; Note: The 625 mg and 250 mg tablet formulations were shown to be bioequivalent in HIV-infected patients receiving multiple doses of 1,250 mg twice daily (under fed conditions). In healthy volunteers, the 250 mg and 625 mg tablets were not bioequivalent; the AUC for the 625 mg tablets was 34% higher than the 250 mg tablets in fasted adults and 24% higher than the 250 mg tablets under fed conditions.
Half-life elimination: 3.5 to 5 hours
Time to peak, serum: 2 to 4 hours
Excretion: Feces (98% to 99%, 78% as metabolites, 22% as unchanged drug); urine (1% to 2%)
Hepatic function impairment: Cmax and AUC were increased 22% and 62%, respectively, in subjects with moderate hepatic impairment when compared with subjects with normal hepatic function. Patients with severe hepatic impairment were not studied.
Tablets (Viracept Oral)
250 mg (per each): $4.86
625 mg (per each): $12.14
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