Drug interactions
Ketoconazole + Oxybutynin
Severity: Moderate
Ketoconazole 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
Ketoconazole strongly inhibits CYP3A4 and can raise oxybutynin concentrations, increasing the likelihood of anticholinergic adverse effects including dry mouth, constipation, drowsiness and confusion.
What this interaction means in plain words
Ketoconazole 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.
Ketoconazole belongs to Anti Fungals; Oxybutynin belongs to Genitourinary.
Why it happens
Inhibition of intestinal and hepatic CYP3A4 metabolism of oxybutynin.
What to do
Monitor for anticholinergic adverse effects and reduce the oxybutynin dose if they occur.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Ketoconazole with Oxybutynin?
MediHelp rates the interaction as moderate. Ketoconazole 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. Ketoconazole strongly inhibits CYP3A4 and can raise oxybutynin concentrations, increasing the likelihood of anticholinergic adverse effects including dry mouth, constipation, drowsiness and confusion.
How serious is the interaction between Ketoconazole 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 and reduce the oxybutynin dose if they occur.
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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