Ampicillin and Ethynodiol diacetate and ethinyl estradiol interaction
Ampicillin and Ethynodiol diacetate and ethinyl estradiol: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Ampicillin label · effective 2026-07-27
Oral Contraceptives : May be less effective and increased breakthrough bleeding may occur.
From the Ethynodiol diacetate and ethinyl estradiol (Kelnor 1/35) label · effective 2023-02-04
A similar association, though less marked, has been suggested for barbiturates, phenylbutazone, phenytoin sodium, and possibly with griseofulvin, ampicillin, and tetracyclines.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.