Drug interactions
Ampicillin + Ethinylestradiol
Severity: Minor
Ampicillin and Ethinylestradiol: 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
Antibiotics were once thought to lower ethinylestradiol levels by disrupting gut flora that recirculate estrogen. Pharmacokinetic and epidemiologic data do not show a consistent loss of contraceptive efficacy with ampicillin, though rare individual failures have been reported.
What this interaction means in plain words
Ampicillin and Ethinylestradiol 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 reduction of enterohepatic recirculation of ethinylestradiol through altered intestinal flora.
What to do
No routine extra contraception is needed; counsel on additional precautions if vomiting or severe diarrhea 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 Ampicillin
- Allopurinol + Ampicillin Moderate
- Ampicillin + Bcg vaccine live Moderate
- Ampicillin + Chloramphenicol Moderate
- Ampicillin + Chloroquine Moderate
- Ampicillin + Cholera vaccine Moderate
- Ampicillin + Demeclocycline Moderate
Frequently asked questions
Can I take Ampicillin with Ethinylestradiol?
MediHelp rates the interaction as minor. Ampicillin and Ethinylestradiol have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Antibiotics were once thought to lower ethinylestradiol levels by disrupting gut flora that recirculate estrogen. Pharmacokinetic and epidemiologic data do not show a consistent loss of contraceptive efficacy with ampicillin, though rare individual failures have been reported.
How serious is the interaction between Ampicillin and Ethinylestradiol?
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 extra contraception is needed; counsel on additional precautions if vomiting or severe diarrhea occurs.
What other medicines interact with Ampicillin?
MediHelp also lists interactions of Ampicillin with, for example, Allopurinol, Bcg vaccine live, Chloramphenicol. The full list is on the Ampicillin page.
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