Drug interactions
Letermovir + Phenobarbitone
Severity: Major
Letermovir and Phenobarbitone: 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
Phenobarbitone may lower letermovir plasma concentrations, which could compromise prevention of cytomegalovirus infection in transplant recipients. Labeling advises against the combination.
What this interaction means in plain words
Letermovir and Phenobarbitone 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; Phenobarbitone belongs to Central Nervous System.
Why it happens
Enzyme induction by phenobarbitone (including UGT and CYP pathways) increases letermovir clearance.
What to do
Avoid the combination and choose a non-inducing anticonvulsant where possible. If it cannot be avoided, monitor for CMV breakthrough.
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 Phenobarbitone
- Cabotegravir + Phenobarbitone Contraindicated
- Doravirine + Phenobarbitone Contraindicated
- Isavuconazole + Phenobarbitone Contraindicated
- Darolutamide + Phenobarbitone Major
- Finerenone + Phenobarbitone Major
- Ivacaftor + Phenobarbitone Major
Frequently asked questions
Can I take Letermovir with Phenobarbitone?
MediHelp rates the interaction as major. Letermovir and Phenobarbitone 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. Phenobarbitone may lower letermovir plasma concentrations, which could compromise prevention of cytomegalovirus infection in transplant recipients. Labeling advises against the combination.
How serious is the interaction between Letermovir and Phenobarbitone?
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 the combination and choose a non-inducing anticonvulsant where possible. If it cannot be avoided, monitor for CMV breakthrough.
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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