Drug interactions
Isoniazid + Oxybutynin
Severity: Minor
Isoniazid 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
Isoniazid can inhibit CYP3A4 to a modest degree and may slightly raise oxybutynin exposure. Increased anticholinergic effects are possible but unlikely to be significant.
What this interaction means in plain words
Isoniazid 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.
Isoniazid belongs to Anti Bacterial; Oxybutynin belongs to Genitourinary.
Why it happens
Weak CYP3A4 inhibition by isoniazid reduces oxybutynin metabolism.
What to do
No routine action is required. Watch for increased anticholinergic effects in frail or elderly patients.
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 Isoniazid
Frequently asked questions
Can I take Isoniazid with Oxybutynin?
MediHelp rates the interaction as minor. Isoniazid 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. Isoniazid can inhibit CYP3A4 to a modest degree and may slightly raise oxybutynin exposure. Increased anticholinergic effects are possible but unlikely to be significant.
How serious is the interaction between Isoniazid 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: No routine action is required. Watch for increased anticholinergic effects in frail or elderly patients.
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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