Drug Interactions of Letermovir Tablets
Concomitant Medications That Are Strictly Contraindicated
Concomitant use with the following drugs is strictly prohibited due to severe risks:
Pimozide: May cause QT interval prolongation and life-threatening arrhythmias (torsades de pointes).
Ergot alkaloids (e.g., ergotamine): May lead to abnormal vasoconstriction and neurotoxic reactions (ergotism).
Third-generation statins (rosuvastatin/pitavastatin/simvastatin) + cyclosporine: Risk of rhabdomyolysis; co-administration is forbidden.
Dabigatran + cyclosporine: Increased bleeding risk; co-administration is forbidden.
Concomitant Medications Requiring Close Monitoring
For the following drugs, close monitoring or dose adjustment is required during co-administration with letermovir:
Amiodarone: Monitor drug concentrations and adverse reactions.
Warfarin: Regularly assess coagulation function (INR value).
Glibenclamide: Intensify blood glucose monitoring.
Atorvastatin: Daily dose must not exceed 20 mg; monitor for myalgia and other symptoms.
Voriconazole: Observe for potential reduction in therapeutic efficacy.
Cyclosporine/sirolimus/tacrolimus: Frequently monitor blood drug concentrations and adjust doses as needed.
Proton pump inhibitors (omeprazole/lansoprazole): Dose adjustment may be required.
Concomitant Medications That Are Not Recommended
Concomitant use with the following 15 classes of drugs is not recommended, as they may reduce letermovir plasma concentrations and impair efficacy:Nafcillin, carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, silymarin, bosentan, St. John’s Wort, efavirenz, etravirine, nevirapine, nelfinavir, modafinil, and related agents.
Additional Important Considerations
CYP2C8 substrates (e.g., repaglinide for diabetes): Intensify blood glucose monitoring.
CYP3A substrates: Refer to the prescribing information for dose adjustments and adverse reaction monitoring.
General advice: Always consult a physician or pharmacist to confirm interaction risks before taking any other medications with letermovir.
Concomitant Use of Letermovir with Other Anti-CMV Drugs
Compatibility with Other Anti-CMV Agents
When used in combination with other anti-CMV drugs that act via inhibition of viral DNA polymerase (e.g., ganciclovir, cidofovir, foscarnet), letermovir does not antagonize their therapeutic effects.
Clinical Implications of Combination Therapy
This compatibility allows clinicians to select multiple antiviral agents with distinct mechanisms for combination therapy based on individual patient conditions. Such regimens can enhance antiviral efficacy without compromising the therapeutic activity of letermovir itself.
