Drug interactions
Letermovir + Oxybutynin
Severity: Moderate
Letermovir and Oxybutynin: 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 inhibits CYP3A4 (moderately), which may increase oxybutynin concentrations. This may intensify anticholinergic adverse effects such as dry mouth, constipation, confusion and urinary retention.
What this interaction means in plain words
Letermovir and Oxybutynin 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 belongs to Anti Virals; Oxybutynin belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4-mediated metabolism of oxybutynin by letermovir.
What to do
Monitor for anticholinergic adverse effects during letermovir therapy and reduce the oxybutynin dose if they develop.
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?
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Other interactions of Oxybutynin
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 Oxybutynin?
MediHelp rates the interaction as moderate. Letermovir and Oxybutynin 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 inhibits CYP3A4 (moderately), which may increase oxybutynin concentrations. This may intensify anticholinergic adverse effects such as dry mouth, constipation, confusion and urinary retention.
How serious is the interaction between Letermovir and Oxybutynin?
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 for anticholinergic adverse effects during letermovir therapy and reduce the oxybutynin dose if they develop.
What other medicines interact with Oxybutynin?
MediHelp also lists interactions of Oxybutynin with, for example, Bethanechol, Clozapine, Potassium chloride. The full list is on the Oxybutynin page.
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