Drug interactions
Diltiazem + Oxybutynin
Severity: Minor
Diltiazem and Oxybutynin: minor 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
Diltiazem inhibits CYP3A4 and may increase oxybutynin concentrations, potentially enhancing anticholinergic effects. The effect is usually modest but may matter in older or frail patients.
What this interaction means in plain words
Diltiazem and Oxybutynin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diltiazem belongs to Cardiovascular; Oxybutynin belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4-mediated oxybutynin metabolism.
What to do
Watch for increased dry mouth, constipation or confusion after starting diltiazem and reduce the oxybutynin dose if needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Oxybutynin
Other interactions of Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Frequently asked questions
Can I take Diltiazem with Oxybutynin?
MediHelp rates the interaction as minor. Diltiazem and Oxybutynin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diltiazem inhibits CYP3A4 and may increase oxybutynin concentrations, potentially enhancing anticholinergic effects. The effect is usually modest but may matter in older or frail patients.
How serious is the interaction between Diltiazem and Oxybutynin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Watch for increased dry mouth, constipation or confusion after starting diltiazem and reduce the oxybutynin dose if needed.
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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