Drug interactions
Estradiol vaginal + Isoniazid
Severity: Minor
Estradiol vaginal and Isoniazid: 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
Systemic absorption of vaginal estradiol is low, and isoniazid is only a weak CYP3A4 inhibitor. A clinically relevant change in estradiol exposure is unlikely.
What this interaction means in plain words
Estradiol vaginal and Isoniazid 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
Theoretical weak CYP3A4 inhibition by isoniazid reducing estradiol metabolism.
What to do
No action is required beyond routine follow-up. Review the dose if breast tenderness or unexpected bleeding occurs.
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 Isoniazid
Frequently asked questions
Can I take Estradiol vaginal with Isoniazid?
MediHelp rates the interaction as minor. Estradiol vaginal and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Systemic absorption of vaginal estradiol is low, and isoniazid is only a weak CYP3A4 inhibitor. A clinically relevant change in estradiol exposure is unlikely.
How serious is the interaction between Estradiol vaginal and Isoniazid?
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 action is required beyond routine follow-up. Review the dose if breast tenderness or unexpected bleeding occurs.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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