Drug interactions
Letermovir + Rifampicin
Severity: Major
Letermovir and Rifampicin: major 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
Rifampicin reduces letermovir exposure, risking loss of antiviral prophylaxis against CMV. The effect can be variable because rifampicin also inhibits transporters initially.
What this interaction means in plain words
Letermovir and Rifampicin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Letermovir belongs to Anti Virals; Rifampicin belongs to Anti Bacterial.
Why it happens
Induction of metabolic enzymes and transporters by rifampicin increases letermovir elimination, after an initial transporter inhibition effect.
What to do
Avoid coadministration and use an alternative antimycobacterial if feasible. If unavoidable, monitor for CMV reactivation.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Letermovir
- Ergotamine + Letermovir Contraindicated
- Letermovir + Pimozide Contraindicated
- Apalutamide + Letermovir Major
- Atorvastatin + Letermovir Major
- Carbamazepine + Letermovir Major
- Colchicine + Letermovir Major
Other interactions of Rifampicin
- Cabotegravir + Rifampicin Contraindicated
- Delamanid + Rifampicin Contraindicated
- Doravirine + Rifampicin Contraindicated
- Ensitrelvir + Rifampicin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
- Isavuconazole + Rifampicin Contraindicated
Frequently asked questions
Can I take Letermovir with Rifampicin?
MediHelp rates the interaction as major. Letermovir and Rifampicin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Rifampicin reduces letermovir exposure, risking loss of antiviral prophylaxis against CMV. The effect can be variable because rifampicin also inhibits transporters initially.
How serious is the interaction between Letermovir and Rifampicin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid coadministration and use an alternative antimycobacterial if feasible. If unavoidable, monitor for CMV reactivation.
What other medicines interact with Letermovir?
MediHelp also lists interactions of Letermovir with, for example, Ergotamine, Pimozide, Apalutamide. The full list is on the Letermovir page.
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