Drug interactions
Fesoterodine + Nefazodone
Severity: Moderate
Fesoterodine and Nefazodone: 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
Nefazodone is a potent CYP3A4 inhibitor and raises exposure to the active metabolite of fesoterodine, 5-hydroxymethyl tolterodine. This can increase anticholinergic adverse effects such as dry mouth, constipation and urinary retention.
What this interaction means in plain words
Fesoterodine and Nefazodone 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
Nefazodone inhibits CYP3A4, which contributes to clearance of the active metabolite of fesoterodine.
What to do
Limit fesoterodine to 4 mg daily with potent 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
Frequently asked questions
Can I take Fesoterodine with Nefazodone?
MediHelp rates the interaction as moderate. Fesoterodine and Nefazodone 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. Nefazodone is a potent CYP3A4 inhibitor and raises exposure to the active metabolite of fesoterodine, 5-hydroxymethyl tolterodine. This can increase anticholinergic adverse effects such as dry mouth, constipation and urinary retention.
How serious is the interaction between Fesoterodine and Nefazodone?
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 potent 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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