Does Letermovir Interact with Cyclosporine?
Letermovir and Cyclosporine have a moderate drug interaction according to U.S. FDA drug labeling data. Co-administration requires dosage adjustment of letermovir to 240 mg once daily in adults and pediatric patients ≥12 years; dose adjustment may be needed in younger patients. The mechanism involves cyclosporine affects letermovir plasma concentrations and the magnitude of cyp3a and oatp1b1/3-mediated interactions. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Letermovir Class
- Cytomegalovirus DNA Terminase Complex Inhibitor
- Cyclosporine Class
- Calcineurin Inhibitor Immunosuppressant
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Letermovir and Cyclosporine occurs because cyclosporine affects letermovir plasma concentrations and the magnitude of cyp3a and oatp1b1/3-mediated interactions. Clinically, this means co-administration requires dosage adjustment of letermovir to 240 mg once daily in adults and pediatric patients ≥12 years; dose adjustment may be needed in younger patients. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Letermovir and your doctor is considering prescribing Cyclosporine (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider