Drug interactions
Atazanavir + Fesoterodine
Severity: Moderate
Atazanavir and Fesoterodine: 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
Atazanavir, especially when boosted, inhibits CYP3A4 and raises exposure to the active metabolite of fesoterodine, increasing anticholinergic adverse effects.
What this interaction means in plain words
Atazanavir and Fesoterodine 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.
Atazanavir belongs to Anti Virals; Fesoterodine belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4 metabolism of the active metabolite of fesoterodine.
What to do
Limit fesoterodine to 4 mg daily with strong CYP3A4 inhibitors and monitor for anticholinergic effects.
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 Fesoterodine
Other interactions of Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Fesoterodine?
MediHelp rates the interaction as moderate. Atazanavir and Fesoterodine 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. Atazanavir, especially when boosted, inhibits CYP3A4 and raises exposure to the active metabolite of fesoterodine, increasing anticholinergic adverse effects.
How serious is the interaction between Atazanavir and Fesoterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit fesoterodine to 4 mg daily with strong CYP3A4 inhibitors and monitor for anticholinergic effects.
What other medicines interact with Fesoterodine?
MediHelp also lists interactions of Fesoterodine with, for example, Bethanechol, Clozapine, Levoketoconazole. The full list is on the Fesoterodine page.
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