Drug interactions
Fosamprenavir + Solifenacin
Severity: Moderate
Fosamprenavir and Solifenacin: 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
Fosamprenavir, whose active form amprenavir inhibits CYP3A4, especially when boosted with ritonavir, can raise solifenacin levels. This may increase anticholinergic effects and QT risk.
What this interaction means in plain words
Fosamprenavir and Solifenacin 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.
Why it happens
CYP3A4 inhibition by amprenavir reduces solifenacin clearance.
What to do
Monitor for anticholinergic and cardiac effects; consider limiting solifenacin to 5 mg daily if boosted regimens are used.
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 Solifenacin
Frequently asked questions
Can I take Fosamprenavir with Solifenacin?
MediHelp rates the interaction as moderate. Fosamprenavir and Solifenacin 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. Fosamprenavir, whose active form amprenavir inhibits CYP3A4, especially when boosted with ritonavir, can raise solifenacin levels. This may increase anticholinergic effects and QT risk.
How serious is the interaction between Fosamprenavir and Solifenacin?
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 and cardiac effects; consider limiting solifenacin to 5 mg daily if boosted regimens are used.
What other medicines interact with Solifenacin?
MediHelp also lists interactions of Solifenacin with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Solifenacin page.
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