Drug interactions
Cimetidine + Tolterodine
Severity: Minor
Cimetidine and Tolterodine: 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
Cimetidine has little effect on tolterodine in most patients. Tolterodine is cleared mainly by CYP2D6, with CYP3A4 as an alternative route.
What this interaction means in plain words
Cimetidine and Tolterodine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Cimetidine belongs to Gastrointestinal Tract; Tolterodine belongs to Genitourinary.
Why it happens
Cimetidine weakly inhibits CYP3A4 and CYP2D6, slightly reducing tolterodine clearance.
What to do
No dose change is generally required; monitor for anticholinergic effects.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Tolterodine
Frequently asked questions
Can I take Cimetidine with Tolterodine?
MediHelp rates the interaction as minor. Cimetidine and Tolterodine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Cimetidine has little effect on tolterodine in most patients. Tolterodine is cleared mainly by CYP2D6, with CYP3A4 as an alternative route.
How serious is the interaction between Cimetidine and Tolterodine?
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 dose change is generally required; monitor for anticholinergic effects.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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