Drug interactions
Letermovir + Voriconazole
Severity: Major
Letermovir and Voriconazole: 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
Letermovir lowers voriconazole concentrations, which may lead to subtherapeutic antifungal exposure and treatment failure in patients at high risk of invasive fungal infection.
What this interaction means in plain words
Letermovir and Voriconazole 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; Voriconazole belongs to Anti Fungals.
Why it happens
Letermovir induces CYP2C19 and CYP2C9, increasing voriconazole metabolism.
What to do
Monitor voriconazole trough concentrations and clinical response, and increase the dose if levels are subtherapeutic; consider an alternative antifungal if needed.
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 Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
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 Letermovir with Voriconazole?
MediHelp rates the interaction as major. Letermovir and Voriconazole 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 lowers voriconazole concentrations, which may lead to subtherapeutic antifungal exposure and treatment failure in patients at high risk of invasive fungal infection.
How serious is the interaction between Letermovir and Voriconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor voriconazole trough concentrations and clinical response, and increase the dose if levels are subtherapeutic; consider an alternative antifungal if needed.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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