Drug interactions
Fesoterodine + Posaconazole
Severity: Moderate
Fesoterodine and Posaconazole: 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
Posaconazole is a strong CYP3A4 inhibitor and raises exposure to the active metabolite of fesoterodine. This increases the risk of antimuscarinic adverse effects such as dry mouth, constipation and urinary retention.
What this interaction means in plain words
Fesoterodine and Posaconazole 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.
Fesoterodine belongs to Genitourinary; Posaconazole belongs to Anti Fungals.
Why it happens
Strong CYP3A4 inhibition by posaconazole reduces clearance of the fesoterodine active metabolite.
What to do
Limit fesoterodine to 4 mg daily during co-administration with strong CYP3A4 inhibitors. Monitor for antimuscarinic adverse 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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Fesoterodine with Posaconazole?
MediHelp rates the interaction as moderate. Fesoterodine and Posaconazole 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. Posaconazole is a strong CYP3A4 inhibitor and raises exposure to the active metabolite of fesoterodine. This increases the risk of antimuscarinic adverse effects such as dry mouth, constipation and urinary retention.
How serious is the interaction between Fesoterodine and Posaconazole?
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 during co-administration with strong CYP3A4 inhibitors. Monitor for antimuscarinic adverse 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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