Drug interactions
Letermovir + Thioridazine
Severity: Major
Letermovir and Thioridazine: 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
Thioridazine may lower letermovir levels, and labeling advises against coadministration. Reduced letermovir exposure could lead to failure of CMV prophylaxis.
What this interaction means in plain words
Letermovir and Thioridazine 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; Thioridazine belongs to Central Nervous System.
Why it happens
Thioridazine is thought to reduce letermovir exposure by enzyme induction; the mechanism is not firmly established.
What to do
Avoid the combination and use another antipsychotic if possible. If unavoidable, 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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Letermovir with Thioridazine?
MediHelp rates the interaction as major. Letermovir and Thioridazine 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. Thioridazine may lower letermovir levels, and labeling advises against coadministration. Reduced letermovir exposure could lead to failure of CMV prophylaxis.
How serious is the interaction between Letermovir and Thioridazine?
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 use another antipsychotic if possible. If unavoidable, 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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