Cytomegalovirus (CMV) prophylaxis, hematopoietic stem cell transplant (HSCT) patients: IV, Oral: 480 mg once daily beginning between day 0 and day 28 postallogeneic HSCT for CMV-seropositive recipients; continue through day 100 posttransplantation.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Note: The Cockcroft-Gault equation should be used to estimate renal function.
CrCl >10 mL/minute:
Oral: No dosage adjustment necessary
IV: No dosage adjustment necessary; use with caution and closely monitor serum creatinine in patients with CrCl <50 mL/minute due to potential accumulation of IV vehicle (hydroxypropyl betadex)
CrCl ≤10 mL/minute: There are no specific dosage adjustments provided in the manufacturer’s labeling; data are insufficient to make dosage recommendations.
ESRD on dialysis: There are no specific dosage adjustments provided in the manufacturer’s labeling; data are insufficient to make dosage recommendations.
Mild or moderate impairment (Child-Pugh class A or B): No dosage adjustment necessary.
Severe impairment (Child-Pugh class C): Use is not recommended.
Refer to adult dosing.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Intravenous [preservative free]:
Prevymis: 240 mg/12 mL (12 mL); 480 mg/24 mL (24 mL)
Tablet, Oral:
Prevymis: 240 mg, 480 mg
No
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Intravenous:
Prevymis: 240 mg/12 mL (12 mL); 480 mg/24 mL (24 mL)
Tablet, Oral:
Prevymis: 240 mg, 480 mg
Oral: Administer with or without food; swallow tablet whole.
IV: Infuse as an IV infusion over 1 hour through a peripheral or central venous catheter; do not administer as IV bolus. Infuse via a 0.2- or 0.22-micron polyethersulfone in-line filter. Not compatible with polyurethane-containing IV administration sets; refer to manufacturer's labeling for compatible infusion sets.
Cytomegalovirus (prophylaxis): Prophylaxis of cytomegalovirus (CMV) infection and disease in adult CMV-seropositive recipients [R+] of an allogeneic hematopoietic stem cell transplant (HSCT)
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Cardiovascular: Peripheral edema (14%)
Central nervous system: Headache (14%), fatigue (13%)
Gastrointestinal: Nausea (27%), diarrhea (26%), vomiting (19%), abdominal pain (12%)
Hematologic & oncologic: Decreased platelet count (grade 4: 27%)
Respiratory: Cough (14%)
1% to 10%:
Cardiovascular: Tachycardia (4%), atrial fibrillation (3%)
Hematologic & oncologic: Decreased hemoglobin (grade 4: 2%)
<1%, postmarketing, and/or case reports: Hypersensitivity reaction
Concomitant administration with pimozide or ergot alkaloids; concomitant administration with pitavastatin and simvastatin when coadministered with cyclosporine.
Canadian labeling: Additional contraindications (not in US labeling): Hypersensitivity to letermovir or any component of the formulation; concomitant administration with bosentan, lovastatin, and rosuvastatin when coadministered with cyclosporine.
Disease-related concerns:
• Hepatic impairment: Use is not recommended in patients with severe impairment (Child-Pugh class C).
• Renal impairment: Use with caution and closely monitor serum creatinine in patients with CrCl <50 mL/minute; accumulation of IV vehicle, hydroxypropyl betadex, may occur. Data are insufficient to make dosage recommendations in patients with CrCl ≤10 mL/minute or in patients on dialysis.
Dosage form specific issues:
• Injection: Contains hydroxypropyl betadex; use injection only in patients unable to take oral therapy.
Other warnings/precautions:
• Appropriate use: Not active against other herpes viruses besides cytomegalovirus (CMV) (Marschall 2012). Additional prophylaxis targeting herpes simplex virus (HSV) in HSV-positive hematopoietic stem cell transplant recipients receiving letermovir may be necessary (Tomblyn 2009).
• Resistance: Patients may have resistance to letermovir due to mutations in UL56. Cross resistance does not occur in populations with substitutions conferring resistance to CMV DNA polymerase inhibitors such as ganciclovir, cidofovir, and foscarnet.
Substrate of CYP2D6 (minor), CYP3A4 (minor), OATP1B1/1B3 (SLCO1B1/1B3), P-glycoprotein/ABCB1 (major), UGT1A1, UGT1A3; Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits CYP3A4 (moderate)
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.
Abemaciclib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Abemaciclib. Management: Monitor for increased abemaciclib toxicities if combined with moderate CYP3A4 inhibitors. Consider reducing the abemaciclib dose in 50 mg decrements if necessary. Risk C: Monitor therapy
Acalabrutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Acalabrutinib. Management: Reduce acalabrutinib dose to 100 mg once daily with concurrent use of a moderate CYP3A4 inhibitor. Monitor patient closely for both acalabrutinib response and evidence of adverse effects with any concurrent use. Risk D: Consider therapy modification
Adagrasib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Adagrasib. Risk C: Monitor therapy
Alfentanil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Alfentanil. Management: If use of alfentanil and moderate 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 (Moderate) may increase the serum concentration of Alfuzosin. Risk C: Monitor therapy
Alitretinoin (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Alitretinoin (Systemic). Risk C: Monitor therapy
ALPRAZolam: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of ALPRAZolam. Management: Consider alternatives to this combination when possible. If combined, consider an alprazolam dose reduction and monitor for increased alprazolam effects and toxicities (eg, sedation, lethargy). Risk D: Consider therapy modification
Amiodarone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Amiodarone. Risk C: Monitor therapy
AmLODIPine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of AmLODIPine. Risk C: Monitor therapy
Apixaban: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Apixaban. Risk C: Monitor therapy
Aprepitant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Aprepitant. Risk X: Avoid combination
ARIPiprazole: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy, indication, or dosage form. Consult full interaction monograph for specific recommendations. Risk C: Monitor therapy
ARIPiprazole Lauroxil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of ARIPiprazole Lauroxil. Risk C: Monitor therapy
Astemizole: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Astemizole. Management: Avoid concomitant use of astemizole and moderate CYP3A4 inhibitors whenever possible. If combined, monitor closely for increased astemizole toxicities, especially for QTc interval prolongation. Risk D: Consider therapy modification
Asunaprevir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Asunaprevir. Risk X: Avoid combination
Atazanavir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Atazanavir. Risk C: Monitor therapy
Atogepant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Atogepant. Risk C: Monitor therapy
Atorvastatin: Letermovir may increase the serum concentration of Atorvastatin. Management: Limit the atorvastatin dose to 20 mg daily when combined with letermovir. When letermovir is coadministered with cyclosporine, the use of atorvastatin (at any dose) is not recommended. Risk D: Consider therapy modification
Avacopan: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Avacopan. Risk C: Monitor therapy
Avanafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Avanafil. Management: The maximum avanafil dose is 50 mg per 24-hour period when used together with a moderate CYP3A4 inhibitor. Patients receiving such a combination should also be monitored more closely for evidence of adverse effects (eg, hypotension, syncope, priapism). Risk D: Consider therapy modification
Avapritinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Avapritinib. Management: Avoid use of moderate CYP3A4 inhibitors with avapritinib. If this combination cannot be avoided, reduce the avapritinib dose to 100 mg daily for the treatment of GIST or to 50 mg daily for the treatment of advanced systemic mastocytosis. Risk D: Consider therapy modification
Axitinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Axitinib. Risk C: Monitor therapy
Barnidipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Barnidipine. Risk C: Monitor therapy
Bedaquiline: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Bedaquiline. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Bedaquiline. Risk C: Monitor therapy
Benidipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Benidipine. Risk C: Monitor therapy
Benzhydrocodone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Benzhydrocodone. Specifically, the concentration of hydrocodone may be increased. Risk C: Monitor therapy
Blonanserin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Blonanserin. Risk C: Monitor therapy
Bortezomib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Bortezomib. Risk C: Monitor therapy
Bosentan: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Bosutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Bosutinib. Risk X: Avoid combination
Brexpiprazole: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Brexpiprazole. Management: The brexpiprazole dose should be reduced to 25% of usual if used together with both a moderate CYP3A4 inhibitor and a strong or moderate CYP2D6 inhibitor, or if a moderate CYP3A4 inhibitor is used in a CYP2D6 poor metabolizer. Risk C: Monitor therapy
Brigatinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with moderate CYP3A4 inhibitors when possible. If such a combination cannot be avoided, reduce the dose of brigatinib by approximately 40% (ie, from 180 mg to 120 mg, from 120 mg to 90 mg, or from 90 mg to 60 mg). Risk D: Consider therapy modification
Bromocriptine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Bromocriptine. Management: The bromocriptine dose should not exceed 1.6 mg daily with use of a moderate CYP3A4 inhibitor. The Cycloset brand specifically recommends this dose limitation, but other bromocriptine products do not make such specific recommendations. Risk D: Consider therapy modification
Budesonide (Oral Inhalation): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Budesonide (Oral Inhalation). Risk C: Monitor therapy
Budesonide (Systemic): CYP3A4 Inhibitors (Moderate) 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 CYP3A4 inhibitors, they should be closely monitored for signs and symptoms of corticosteroid excess. Risk D: Consider therapy modification
Budesonide (Topical): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Budesonide (Topical). Risk X: Avoid combination
Buprenorphine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Buprenorphine. Risk C: Monitor therapy
BusPIRone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of BusPIRone. Risk C: Monitor therapy
Cabozantinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Cabozantinib. Risk C: Monitor therapy
Cannabis: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be increased. Risk C: Monitor therapy
Cariprazine: CYP3A4 Inhibitors (Moderate) 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 (Moderate) may increase the serum concentration of Cariprazine. Risk C: Monitor therapy
Ceritinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ceritinib. Risk C: Monitor therapy
Cilostazol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Cilostazol. Management: Decrease the dose of cilostazol to 50 mg twice daily when combined with moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Cisapride: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Cisapride. Management: Consider alternatives to this combination. Prescribing information for some moderate CYP3A4 inhibitors state coadministration with cisapride is contraindicated, while some others recommend monitoring and dose titration. Risk D: Consider therapy modification
Clindamycin (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Clindamycin (Systemic). Risk C: Monitor therapy
CloZAPine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of CloZAPine. Risk C: Monitor therapy
Cobimetinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Cobimetinib. Management: Avoid this combination when possible. If concurrent short term (14 days or less) use cannot be avoided, reduce the cobimetinib dose from 60 mg to 20 mg daily. Avoid concomitant use in patients already receiving reduced cobimetinib doses. Risk D: Consider therapy modification
Codeine: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Codeine. Risk C: Monitor therapy
Colchicine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Colchicine. Management: Reduce colchicine dose as directed when using with a moderate CYP3A4 inhibitor, and increase monitoring for colchicine-related toxicity. See interaction monograph for details. Use extra caution in patients with impaired renal and/or hepatic function. Risk D: Consider therapy modification
Conivaptan: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Conivaptan. Risk C: Monitor therapy
Copanlisib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Copanlisib. Risk C: Monitor therapy
Crizotinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Crizotinib. Risk C: Monitor therapy
CycloSPORINE (Systemic): Letermovir may increase the serum concentration of CycloSPORINE (Systemic). CycloSPORINE (Systemic) may increase the serum concentration of Letermovir. Management: Decrease the letermovir dose to 240 mg daily when combined with cyclosporine. Additionally, monitor for increased cyclosporine concentrations and toxicities when combined with letermovir. Risk D: Consider therapy modification
Dabrafenib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dabrafenib. Risk C: Monitor therapy
Dapoxetine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dapoxetine. Management: The dose of dapoxetine should be limited to 30 mg per day when used together with a moderate inhibitor of CYP3A4. Risk D: Consider therapy modification
Daridorexant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Daridorexant. Management: Limit the daridorexant dose to 25 mg, no more than once per night, when combined with moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Darifenacin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Darifenacin. Risk C: Monitor therapy
Darolutamide: May increase the serum concentration of OATP1B1/1B3 (SLCO1B1/1B3) Substrates (Clinically Relevant with Inhibitors). Risk C: Monitor therapy
Dasatinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dasatinib. Risk C: Monitor therapy
Deflazacort: CYP3A4 Inhibitors (Moderate) 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 (Moderate) may increase the serum concentration of Delamanid. Risk C: Monitor therapy
DexAMETHasone (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of DexAMETHasone (Systemic). Risk C: Monitor therapy
DiazePAM: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of DiazePAM. Risk C: Monitor therapy
DilTIAZem: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of DilTIAZem. Risk C: Monitor therapy
Disopyramide: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Disopyramide. Risk C: Monitor therapy
DOCEtaxel: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of DOCEtaxel. Risk C: Monitor therapy
Dofetilide: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dofetilide. Risk C: Monitor therapy
Domperidone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Domperidone. Risk X: Avoid combination
DOXOrubicin (Conventional): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of DOXOrubicin (Conventional). Risk X: Avoid combination
Dronabinol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dronabinol. Risk C: Monitor therapy
Dronedarone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Dronedarone. Risk C: Monitor therapy
Ebastine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ebastine. Risk C: Monitor therapy
Elbasvir and Grazoprevir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Elbasvir and Grazoprevir. Risk C: Monitor therapy
Eletriptan: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Eletriptan. Risk X: Avoid combination
Elexacaftor, Tezacaftor, and Ivacaftor: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Elexacaftor, Tezacaftor, and Ivacaftor. Management: When combined with moderate CYP3A4 inhibitors, two elexacaftor/tezacaftor/ivacaftor (100 mg/50 mg/75 mg) tablets should be given in the morning, every other day. Ivacaftor (150 mg) should be given in the morning, every other day on alternate days. Risk D: Consider therapy modification
Eliglustat: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Eliglustat. Management: Reduce eliglustat dose to 84 mg daily in CYP2D6 EMs when used with moderate CYP3A4 inhibitors. Avoid use of moderate CYP3A4 inhibitors in CYP2D6 IMs or PMs. Use in CYP2D6 EMs or IMs also taking strong or moderate CYP2D6 inhibitors is contraindicated. Risk D: Consider therapy modification
Eltrombopag: May increase the serum concentration of OATP1B1/1B3 (SLCO1B1/1B3) Substrates (Clinically Relevant with Inhibitors). Risk C: Monitor therapy
Encorafenib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Encorafenib. Management: Avoid use of encorafenib and moderate CYP3A4 inhibitors when possible. If combined, decrease the encorafenib dose from 450 mg to 225 mg; 300 mg to 150 mg; and 225 mg or 150 mg to 75 mg. Resume prior dose once inhibitor discontinued for 3 to 5 half-lives. Risk D: Consider therapy modification
Entrectinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Entrectinib. Management: Avoid moderate CYP3A4 inhibitors during treatment with entrectinib. Reduce dose to 200 mg/day if combination cannot be avoided in adults and those 12 yrs of age or older with a BSA of at least 1.5 square meters. Avoid if BSA is less than 1.5 square meters Risk D: Consider therapy modification
Eplerenone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Eplerenone. Management: If coadministered with moderate CYP3A4 inhibitors, the max dose of eplerenone is 25 mg daily if used for heart failure; if used for hypertension initiate eplerenone 25 mg daily, titrate to max 25 mg twice daily. Risk D: Consider therapy modification
Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates): Letermovir may increase the serum concentration of Ergot Derivatives (Vasoconstrictive CYP3A4 Substrates). Risk X: Avoid combination
Erlotinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Erlotinib. Risk C: Monitor therapy
Erythromycin (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Erythromycin (Systemic). Risk C: Monitor therapy
Eszopiclone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Eszopiclone. Risk C: Monitor therapy
Etravirine: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Everolimus: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Everolimus. Risk C: Monitor therapy
Fedratinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Fedratinib. Risk C: Monitor therapy
Felodipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Felodipine. Risk C: Monitor therapy
FentaNYL: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of FentaNYL. Management: Consider fentanyl dose reductions when combined with a moderate 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
Fexinidazole: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Fexinidazole. Management: Avoid use of fexinidazole and moderate CYP3A4 inhibitors when possible. If combined, monitor for reduced fexinidazole efficacy. Risk D: Consider therapy modification
Finerenone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Finerenone. Risk C: Monitor therapy
Flibanserin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Flibanserin. Management: Use of flibanserin with moderate 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 (Moderate) may increase the serum concentration of Fluticasone (Nasal). Risk C: Monitor therapy
Fluticasone (Oral Inhalation): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Fluticasone (Oral Inhalation). Risk C: Monitor therapy
Fosamprenavir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Fosamprenavir. Risk C: Monitor therapy
Fosaprepitant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Fosaprepitant. Risk X: Avoid combination
Gemfibrozil: May increase the serum concentration of OATP1B1/1B3 (SLCO1B1/1B3) Substrates (Clinically Relevant with Inhibitors). Risk C: Monitor therapy
Gilteritinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Gilteritinib. Risk C: Monitor therapy
Glasdegib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Glasdegib. Risk C: Monitor therapy
GlyBURIDE: Letermovir may increase the serum concentration of GlyBURIDE. Risk C: Monitor therapy
GuanFACINE: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of GuanFACINE. Management: Reduce the extended-release guanfacine dose 50% when combined with a moderate CYP3A4 inhibitor. Monitor for increased guanfacine toxicities when these agents are combined. Risk D: Consider therapy modification
Halofantrine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Halofantrine. Risk C: Monitor therapy
HMG-CoA Reductase Inhibitors (Statins): Letermovir may increase the serum concentration of HMG-CoA Reductase Inhibitors (Statins). Risk C: Monitor therapy
HYDROcodone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of HYDROcodone. Risk C: Monitor therapy
Ibrutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ibrutinib. Management: When treating B-cell malignancies, decrease ibrutinib to 280 mg daily when combined with moderate CYP3A4 inhibitors. When treating graft versus host disease, monitor patients closely and reduce the ibrutinib dose as needed based on adverse reactions. Risk D: Consider therapy modification
Ifosfamide: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Ifosfamide. Risk C: Monitor therapy
Iloperidone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Iloperidone. Risk C: Monitor therapy
Infigratinib: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Infigratinib. CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Infigratinib. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Infigratinib. Risk X: Avoid combination
Irinotecan Products: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Irinotecan Products. Specifically, the serum concentration of SN-38 may be increased. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Irinotecan Products. Risk C: Monitor therapy
Isavuconazonium Sulfate: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Isavuconazonium Sulfate. Specifically, CYP3A4 Inhibitors (Moderate) may increase isavuconazole serum concentrations. Risk C: Monitor therapy
Isradipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Isradipine. Risk C: Monitor therapy
Itraconazole: May increase the serum concentration of Letermovir. Letermovir may decrease the serum concentration of Itraconazole. Risk C: Monitor therapy
Ivabradine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ivabradine. Risk X: Avoid combination
Ivacaftor: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions may be required; consult full drug interaction monograph content for age- and weight-specific dosage recommendations. Risk D: Consider therapy modification
Ivosidenib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ivosidenib. Management: Avoid use of moderate CYP3A4 inhibitors with ivosidenib whenever possible. If combined, monitor for increased ivosidenib toxicities, including QTc prolongation. Risk D: Consider therapy modification
Ixabepilone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ixabepilone. Risk C: Monitor therapy
Lapatinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lapatinib. Risk C: Monitor therapy
Larotrectinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Larotrectinib. Risk C: Monitor therapy
Lefamulin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lefamulin. Management: Monitor for lefamulin adverse effects during coadministration of lefamulin tablets with moderate CYP3A4 inhibitors. Risk C: Monitor therapy
Leflunomide: May increase the serum concentration of OATP1B1/1B3 (SLCO1B1/1B3) Substrates (Clinically Relevant with Inhibitors). Risk C: Monitor therapy
Lemborexant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lemborexant. Risk X: Avoid combination
Lercanidipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lercanidipine. Risk C: Monitor therapy
Levamlodipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Levamlodipine. Risk C: Monitor therapy
Levoketoconazole: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Levoketoconazole. Risk C: Monitor therapy
Levomethadone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Levomethadone. Risk C: Monitor therapy
Levomilnacipran: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Levomilnacipran. Risk C: Monitor therapy
Lidocaine (Systemic): CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Lidocaine (Systemic). Specifically, concentrations of monoethylglycinexylidide (MEGX) may be increased. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lidocaine (Systemic). Risk C: Monitor therapy
Lomitapide: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lomitapide. Risk X: Avoid combination
Lonafarnib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lonafarnib. Risk X: Avoid combination
Lovastatin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lovastatin. Risk C: Monitor therapy
Lumacaftor and Ivacaftor: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors or Inducers). Lumacaftor and Ivacaftor may decrease the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors or Inducers). Risk C: Monitor therapy
Lumateperone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lumateperone. Management: Limit the lumateperone dose to 21 mg once daily when used with a moderate CYP3A4 inhibitor. Risk D: Consider therapy modification
Lurasidone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lurasidone. Management: US labeling recommends reducing lurasidone dose by 50% with a moderate CYP3A4 inhibitor and initiating 20 mg/day, max 80 mg/day. Some non-US labels recommend initiating lurasidone 20 mg/day, max 40 mg/day. Avoid concurrent use of grapefruit products. Risk D: Consider therapy modification
Lurbinectedin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Lurbinectedin. Management: Avoid concomitant use of lurbinectedin and moderate CYP3A4 inhibitors when possible. If combined, consider a lurbinectedin dose reduction as clinically indicated. Risk D: Consider therapy modification
Macitentan: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Macitentan. Risk C: Monitor therapy
Manidipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Manidipine. Risk C: Monitor therapy
Maraviroc: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Maraviroc. Risk C: Monitor therapy
Mavacamten: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Mavacamten. Management: Start mavacamten at 5 mg/day if stable on a moderate CYP3A4 inhibitor. For those stable on mavacamten who are initiating a moderate CYP3A4 inhibitor, reduce mavacamten dose by one dose level. Risk D: Consider therapy modification
Meperidine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Meperidine. Risk C: Monitor therapy
Methadone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Methadone. Management: If coadministration with moderate CYP3A4 inhibitors is necessary, consider methadone dose reductions until stable effects are achieved. Monitor patients closely for respiratory depression and sedation. Risk D: Consider therapy modification
MethylPREDNISolone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of MethylPREDNISolone. Risk C: Monitor therapy
Methysergide: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Methysergide. Risk X: Avoid combination
Midazolam: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Midazolam. Management: Avoid concomitant use of nasal midazolam and moderate CYP3A4 inhibitors. Consider alternatives to use with oral midazolam whenever possible and consider using lower midazolam doses. Monitor patients for sedation and respiratory depression if combined. Risk D: Consider therapy modification
Midostaurin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Midostaurin. Risk C: Monitor therapy
MiFEPRIStone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of MiFEPRIStone. Risk C: Monitor therapy
Mirodenafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Mirodenafil. Risk C: Monitor therapy
Mitapivat: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Mitapivat. Management: When coadministered with moderate CYP3A4 inhibitors, doses of mitapivat should not exceed 20 mg twice daily. Additionally, patients should be monitored for changes in hemoglobin response and increased mitapivat adverse effects. Risk D: Consider therapy modification
Mobocertinib: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Mobocertinib. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Mobocertinib. Management: Avoid use of moderate CYP3A4 inhibitors with mobocertinib when possible. If combined, the mobocertinib dose should be reduced by approximately 50% (ie, from 160 mg to 80 mg, 120 mg to 40 mg, or 80 mg to 40 mg). Monitor QTc interval closely. Risk D: Consider therapy modification
Modafinil: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Nafcillin: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Naldemedine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Naldemedine. Risk C: Monitor therapy
Nalfurafine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Nalfurafine. Risk C: Monitor therapy
Naloxegol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Naloxegol. Management: The use of naloxegol and moderate CYP3A4 inhibitors should be avoided. If concurrent use is unavoidable, reduce naloxegol dose to 12.5 mg once daily and monitor for signs of opiate withdrawal (eg, hyperhidrosis, chills, diarrhea, anxiety, irritability). Risk D: Consider therapy modification
Neratinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Neratinib. Risk C: Monitor therapy
Nevirapine: May diminish the therapeutic effect of Letermovir. Risk X: Avoid combination
NIFEdipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of NIFEdipine. Risk C: Monitor therapy
Nilotinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Nilotinib. Risk C: Monitor therapy
NiMODipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of NiMODipine. Risk C: Monitor therapy
Nisoldipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Nisoldipine. Risk X: Avoid combination
Nitrendipine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Nitrendipine. Risk C: Monitor therapy
Olaparib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Olaparib. Management: Avoid use of moderate CYP3A4 inhibitors with olaparib, if possible. If such concurrent use cannot be avoided, the dose of olaparib tablets should be reduced to 150 mg twice daily and the dose of olaparib capsules should be reduced to 200 mg twice daily. Risk D: Consider therapy modification
Oliceridine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Oliceridine. Risk C: Monitor therapy
Olmutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Olmutinib. Risk C: Monitor therapy
Orelabrutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Orelabrutinib. Risk X: Avoid combination
OxyCODONE: CYP3A4 Inhibitors (Moderate) 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 (Moderate) may increase the serum concentration of PACLitaxel (Conventional). Risk C: Monitor therapy
PACLitaxel (Protein Bound): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of PACLitaxel (Protein Bound). Risk C: Monitor therapy
Pacritinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Pacritinib. Risk X: Avoid combination
Palbociclib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Palbociclib. Risk C: Monitor therapy
Palovarotene: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Palovarotene. Risk C: Monitor therapy
Panobinostat: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Panobinostat. Risk C: Monitor therapy
PAZOPanib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of PAZOPanib. Risk C: Monitor therapy
Pemigatinib: CYP3A4 Inhibitors (Moderate) 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 moderate inhibitor once 3 half-lives of the inhibitor has passed. Risk D: Consider therapy modification
Pexidartinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Pexidartinib. Management: Avoid use of pexidartinib with moderate CYP3A4 inhibitors if possible. If combined, the 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
P-glycoprotein/ABCB1 Inducers: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Pimavanserin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Pimavanserin. Risk C: Monitor therapy
Pimecrolimus: CYP3A4 Inhibitors (Moderate) may decrease the metabolism of Pimecrolimus. Risk C: Monitor therapy
Pimozide: Letermovir may increase the serum concentration of Pimozide. Risk X: Avoid combination
Piperaquine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Piperaquine. Risk C: Monitor therapy
Pitavastatin: Letermovir may increase the serum concentration of Pitavastatin. Risk X: Avoid combination
PONATinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of PONATinib. Risk C: Monitor therapy
Prazepam: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Prazepam. Risk C: Monitor therapy
Praziquantel: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Praziquantel. Risk C: Monitor therapy
QUEtiapine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of QUEtiapine. Risk C: Monitor therapy
QuiNIDine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of QuiNIDine. Risk C: Monitor therapy
Quinidine (Non-Therapeutic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Quinidine (Non-Therapeutic). Risk C: Monitor therapy
QuiNINE: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of QuiNINE. Risk C: Monitor therapy
Ranolazine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ranolazine. Management: Limit the ranolazine dose to a maximum of 500 mg twice daily in patients concurrently receiving moderate CYP3A4 inhibitors. Monitor for increased ranolazine effects and toxicities during concomitant use. Risk D: Consider therapy modification
Red Yeast Rice: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Red Yeast Rice. Risk C: Monitor therapy
Regorafenib: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Regorafenib. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Regorafenib. Risk C: Monitor therapy
Repaglinide: Letermovir may increase the serum concentration of Repaglinide. Management: Monitor for increased repaglinide effects/toxicities (ie, hypoglycemia) if combined with letermovir. When letermovir is coadministered with cyclosporine, the use of repaglinide is not recommended. Risk C: Monitor therapy
Ribociclib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ribociclib. Risk C: Monitor therapy
Rimegepant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Rimegepant. Management: If taking rimegepant for the acute treatment of migraine, avoid a second dose of rimegepant within 48 hours when used concomitantly with moderate CYP3A4 inhibitors. No dose adjustment needed if using rimegepant for prevention of episodic migraine. Risk D: Consider therapy modification
Rivaroxaban: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Rivaroxaban. This warning is more specifically for drugs that are inhibitors of both CYP3A4 and P-glycoprotein. For erythromycin, refer to more specific erythromycin-rivaroxaban monograph recommendations. Risk C: Monitor therapy
Roflumilast-Containing Products: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Roflumilast-Containing Products. Risk C: Monitor therapy
Rosiglitazone: Letermovir may increase the serum concentration of Rosiglitazone. Risk C: Monitor therapy
Rupatadine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Rupatadine. Risk C: Monitor therapy
Ruxolitinib (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ruxolitinib (Systemic). Risk C: Monitor therapy
Salmeterol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Salmeterol. Risk C: Monitor therapy
Saquinavir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Saquinavir. Risk C: Monitor therapy
SAXagliptin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of SAXagliptin. Risk C: Monitor therapy
Selpercatinib: CYP3A4 Inhibitors (Moderate) 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 80 mg twice/day, or from 160 mg twice/day to 120 mg twice/day. Risk D: Consider therapy modification
Selumetinib: CYP3A4 Inhibitors (Moderate) 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 (Moderate) may increase the serum concentration of Sertindole. Risk X: Avoid combination
Sildenafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Sildenafil. Risk C: Monitor therapy
Silodosin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Silodosin. Risk C: Monitor therapy
Simeprevir: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Simeprevir. Risk X: Avoid combination
Simvastatin: Letermovir may increase the serum concentration of Simvastatin. Risk X: Avoid combination
Sirolimus (Conventional): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Sirolimus (Conventional). Management: Monitor for increased serum concentrations of sirolimus if combined with a moderate CYP3A4 inhibitor. Lower initial sirolimus doses or sirolimus dose reductions will likely be required. Risk D: Consider therapy modification
Sirolimus (Protein Bound): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Sirolimus (Protein Bound). Management: Reduce the dose of protein bound sirolimus to 56 mg/m2 when used concomitantly with a moderate CYP3A4 inhibitor. Risk D: Consider therapy modification
Solifenacin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Solifenacin. Risk C: Monitor therapy
Sonidegib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Sonidegib. Management: Avoid concomitant use of sonidegib and moderate CYP3A4 inhibitors when possible. When concomitant use cannot be avoided, limit CYP3A4 inhibitor use to less than 14 days and monitor for sonidegib toxicity (particularly musculoskeletal adverse reactions). Risk D: Consider therapy modification
SUNItinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of SUNItinib. Risk C: Monitor therapy
Suvorexant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Suvorexant. Management: The recommended dose of suvorexant is 5 mg daily in patients receiving a moderate CYP3A4 inhibitor. The dose can be increased to 10 mg daily (maximum dose) if necessary for efficacy. Risk D: Consider therapy modification
Tacrolimus (Systemic): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tacrolimus (Systemic). Risk C: Monitor therapy
Tacrolimus (Topical): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tacrolimus (Topical). Risk C: Monitor therapy
Tadalafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tadalafil. Risk C: Monitor therapy
Tamsulosin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tamsulosin. Risk C: Monitor therapy
Tazemetostat: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tazemetostat. Management: Avoid when possible. If combined, reduce tazemetostat dose from 800 mg twice daily to 400 mg twice daily, from 600 mg twice daily to 400 mg in AM and 200 mg in PM, or from 400 mg twice daily to 200 mg twice daily. Risk D: Consider therapy modification
Telithromycin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Telithromycin. Risk C: Monitor therapy
Temsirolimus: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Temsirolimus. Specifically, concentrations of sirolimus may be increased. Risk C: Monitor therapy
Terfenadine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Terfenadine. Risk C: Monitor therapy
Teriflunomide: May increase the serum concentration of OATP1B1/1B3 (SLCO1B1/1B3) Substrates (Clinically Relevant with Inhibitors). Risk C: Monitor therapy
Tetrahydrocannabinol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tetrahydrocannabinol. Risk C: Monitor therapy
Tetrahydrocannabinol and Cannabidiol: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tetrahydrocannabinol and Cannabidiol. Risk C: Monitor therapy
Tezacaftor and Ivacaftor: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tezacaftor and Ivacaftor. Management: If combined with moderate CYP3A4 inhibitors, give tezacaftor/ivacaftor in the morning, every other day; give ivacaftor in the morning, every other day on alternate days. Tezacaftor/ivacaftor dose depends on age and weight; see full Lexi-Interact monograph Risk D: Consider therapy modification
Thioridazine: May diminish the therapeutic effect of Letermovir. Risk X: Avoid combination
Thiotepa: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Thiotepa. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Thiotepa. Risk C: Monitor therapy
Ticagrelor: CYP3A4 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Ticagrelor. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ticagrelor. Risk C: Monitor therapy
Tofacitinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tofacitinib. Risk C: Monitor therapy
Tolterodine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tolterodine. Risk C: Monitor therapy
Tolvaptan: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Tolvaptan. Management: Avoid this combination with Samsca brand of tolvaptan. Reduce dose for Jynarque brand: 90 mg AM and 30 mg PM, reduce to 45 mg AM and 15 mg PM; 60 mg AM and 30 mg PM, reduce to 30 mg AM and 15 mg PM; 45 mg AM and 15 mg PM, reduce to 15 mg AM and PM. Risk D: Consider therapy modification
Toremifene: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Toremifene. Risk C: Monitor therapy
Trabectedin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Trabectedin. Risk C: Monitor therapy
TraMADol: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of TraMADol. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of TraMADol. Risk C: Monitor therapy
TraZODone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of TraZODone. Risk C: Monitor therapy
Triazolam: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Triazolam. Management: Consider triazolam dose reduction in patients receiving concomitant moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Ubrogepant: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ubrogepant. Management: Use an initial ubrogepant dose of 50 mg and avoid a second dose for 24 hours when used with moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Udenafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Udenafil. Risk C: Monitor therapy
UGT1A1 Inducers: May decrease the serum concentration of Letermovir. Risk X: Avoid combination
Ulipristal: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Ulipristal. Risk C: Monitor therapy
Valbenazine: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Valbenazine. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Valbenazine. Risk C: Monitor therapy
Vardenafil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vardenafil. Management: Limit Levitra (vardenafil) dose to a single 5 mg dose within a 24-hour period if combined with moderate CYP3A4 inhibitors. Avoid concomitant use of Staxyn (vardenafil) and moderate CYP3A4 inhibitors. Combined use is contraindicated outside of the US. Risk D: Consider therapy modification
Vemurafenib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vemurafenib. Risk C: Monitor therapy
Venetoclax: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Venetoclax. Management: Reduce the venetoclax dose by at least 50% in patients requiring concomitant treatment with moderate CYP3A4 inhibitors. Resume the previous venetoclax dose 2 to 3 days after discontinuation of moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Verapamil: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Verapamil. Risk C: Monitor therapy
Vilazodone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vilazodone. Risk C: Monitor therapy
VinBLAStine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of VinBLAStine. Risk C: Monitor therapy
VinCRIStine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of VinCRIStine. Risk C: Monitor therapy
VinCRIStine (Liposomal): CYP3A4 Inhibitors (Moderate) may increase the serum concentration of VinCRIStine (Liposomal). Risk C: Monitor therapy
Vindesine: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vindesine. Risk C: Monitor therapy
Vinflunine: CYP3A4 Inhibitors (Moderate) may increase serum concentrations of the active metabolite(s) of Vinflunine. CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vinflunine. Risk C: Monitor therapy
Voclosporin: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Voclosporin. Management: Decrease the voclosporin dose to 15.8 mg in the morning and 7.9 mg in the evening when combined with moderate CYP3A4 inhibitors. Risk D: Consider therapy modification
Vorapaxar: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Vorapaxar. Risk C: Monitor therapy
Voriconazole: Letermovir may decrease the serum concentration of Voriconazole. Management: If concomitant administration of voriconazole with letermovir cannot be avoided, monitor for reduced voriconazole serum concentrations and efficacy. Risk D: Consider therapy modification
Warfarin: Letermovir may decrease the serum concentration of Warfarin. Risk C: Monitor therapy
Zanubrutinib: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Zanubrutinib. Management: Decrease the zanubrutinib dose to 80 mg twice daily during coadministration with a moderate CYP3A4 inhibitor. Further dose adjustments may be required for zanubrutinib toxicities, refer to prescribing information for details. Risk D: Consider therapy modification
Zopiclone: CYP3A4 Inhibitors (Moderate) may increase the serum concentration of Zopiclone. Risk C: Monitor therapy
Adverse events were observed in some animal reproduction studies.
It is not known if letermovir is present in breast milk. According to the manufacturer, the decision to breastfeed during therapy should consider the risk of infant exposure, the benefits of breastfeeding to the infant, and the benefits of treatment to the mother.
Monitor for cytomegalovirus (CMV) reactivation; serum creatinine (especially in patients with CrCl <50 mL/minute [due to potential accumulation of IV vehicle hydroxypropyl betadex])
Letermovir inhibits cytomegalovirus (CMV) replication by targeting the CMV DNA terminase complex (pUL51, pUL56, pUL89), which is required for viral DNA processing and packaging. Letermovir affects production of genome unit lengths and alters virion maturation.
Distribution: IV: 45.5 L
Protein binding: 99%
Metabolism: Hepatic via UGT1A1/1A3 (minor)
Bioavailability: Oral: Healthy subjects (without cyclosporine): 94%; Hematopoietic stem cell transplant (HSCT) recipients (480 mg orally once daily without cyclosporine): 35%; HSCT recipients (240 mg orally once daily with cyclosporine): 85%
Half-life elimination: 12 hours
Time to peak: 1.5 to 3 hours
Excretion: Feces: 93% (70% as unchanged drug); urine: <2%
Altered kidney function: Letermovir AUC was approximately 1.9- and 1.4-fold higher in subjects with moderate (eGFR ≥30 to 59 mL/minute/1.73m2) and severe (eGFR <30 mL/minute/1.73m2) renal impairment, respectively (compared to healthy subjects [eGFR ≥90 mL/minute/1.73m2]; Kropeit 2017b).
Hepatic function impairment: Letermovir AUC was approximately 1.6- and 3.8-fold higher in female subjects with moderate (Child-Pugh class B) and severe (Child-Pugh class C) hepatic impairment, respectively, compared to healthy female subjects (Kropeit 2017a).
Solution (Prevymis Intravenous)
240MG/12ML (per mL): $32.81
480MG/24ML (per mL): $16.40
Tablets (Prevymis Oral)
240 mg (per each): $284.42
480 mg (per each): $284.42
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