Drug interactions
Oxybutynin + Rifampin
Severity: Moderate
Oxybutynin and Rifampin: 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
Rifampin is a strong CYP3A4 inducer and can lower oxybutynin concentrations, particularly oral doses subject to first-pass metabolism. This may reduce control of bladder symptoms.
What this interaction means in plain words
Oxybutynin and Rifampin 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
Induction of CYP3A4 increasing oxybutynin metabolism.
What to do
Monitor for reduced symptom control and increase the oxybutynin dose or switch agent if needed. Reassess the dose when rifampin is stopped.
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
Frequently asked questions
Can I take Oxybutynin with Rifampin?
MediHelp rates the interaction as moderate. Oxybutynin and Rifampin 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. Rifampin is a strong CYP3A4 inducer and can lower oxybutynin concentrations, particularly oral doses subject to first-pass metabolism. This may reduce control of bladder symptoms.
How serious is the interaction between Oxybutynin and Rifampin?
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 reduced symptom control and increase the oxybutynin dose or switch agent if needed. Reassess the dose when rifampin is stopped.
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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