Drug interactions
Irinotecan + Letermovir
Severity: Moderate
Irinotecan and Letermovir: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Letermovir is a moderate CYP3A inhibitor and also inhibits OATP1B1/3, which may raise irinotecan and SN-38 exposure. Increased toxicity such as neutropenia and diarrhea is possible. No dedicated studies exist.
What this interaction means in plain words
Irinotecan and Letermovir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Irinotecan belongs to Oncology; Letermovir belongs to Anti Virals.
Why it happens
Letermovir inhibits CYP3A4 and OATP1B1/3, reducing irinotecan and SN-38 clearance.
What to do
Monitor blood counts and diarrhea closely and reduce irinotecan dose if toxicity occurs.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Irinotecan and Letermovir, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Irinotecan
- Clozapine + Irinotecan Contraindicated
- Irinotecan + Sacituzumab govitecan Contraindicated
- Adenovirus types 4 and 7 live + Irinotecan Major
- Apalutamide + Irinotecan Major
- Atazanavir + Irinotecan Major
- Carbamazepine + Irinotecan Major
Other interactions of Letermovir
- Ergotamine + Letermovir Contraindicated
- Letermovir + Pimozide Contraindicated
- Apalutamide + Letermovir Major
- Atorvastatin + Letermovir Major
- Carbamazepine + Letermovir Major
- Colchicine + Letermovir Major
Frequently asked questions
Can I take Irinotecan with Letermovir?
MediHelp rates the interaction as moderate. Irinotecan and Letermovir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Letermovir is a moderate CYP3A inhibitor and also inhibits OATP1B1/3, which may raise irinotecan and SN-38 exposure. Increased toxicity such as neutropenia and diarrhea is possible. No dedicated studies exist.
How serious is the interaction between Irinotecan and Letermovir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood counts and diarrhea closely and reduce irinotecan dose if toxicity occurs.
What other medicines interact with Irinotecan?
MediHelp also lists interactions of Irinotecan with, for example, Clozapine, Sacituzumab govitecan, Adenovirus types 4 and 7 live. The full list is on the Irinotecan page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
