Drug interactions
Cimetidine + Mestranol
Severity: Minor
Cimetidine and Mestranol: 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
Mestranol is converted to ethinylestradiol and metabolised by CYP enzymes. Cimetidine may modestly raise estrogen exposure, which is unlikely to be clinically significant.
What this interaction means in plain words
Cimetidine and Mestranol have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Cimetidine inhibition of hepatic CYP metabolism of estrogens.
What to do
No routine action is needed; monitor for estrogenic adverse effects such as breast tenderness or nausea.
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
Frequently asked questions
Can I take Cimetidine with Mestranol?
MediHelp rates the interaction as minor. Cimetidine and Mestranol have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Mestranol is converted to ethinylestradiol and metabolised by CYP enzymes. Cimetidine may modestly raise estrogen exposure, which is unlikely to be clinically significant.
How serious is the interaction between Cimetidine and Mestranol?
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 needed; monitor for estrogenic adverse effects such as breast tenderness or nausea.
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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