Aminopenicillin antibiotic
Amoxicillin with the birth control pill
Many women of reproductive age take a combined or progestogen-only oral contraceptive while also using a chronic medication such as Amoxicillin (Amoxicillin). The combination is generally fine at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, 1000/62.5mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Amoxicillin can affect contraceptive efficacy
Combined and progestogen-only contraceptives are metabolised through CYP3A4. Strong CYP3A4 inducers (some antiepileptics, rifampicin, St John's Wort) lower contraceptive plasma levels and reduce efficacy. Whether Amoxicillin acts on CYP3A4 determines whether Amoxicillin affects contraception. Most agents in Aminopenicillin antibiotic have no clinically meaningful effect on the pill at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, 1000/62.5mg.
Practical guidance
According to the prescribing information for Amoxicillin, women on hormonal contraception should review Amoxicillin with the prescribing pharmacist or doctor. Where an interaction is documented, additional barrier contraception or switching to a non-oral method (IUD, implant) for the duration of Amoxicillin therapy is the standard mitigation.
Frequently asked questions
Will Amoxicillin make my pill less effective? ▾
Most Aminopenicillin antibiotic medications at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, 1000/62.5mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Amoxicillin states whether the interaction is meaningful.
Do I need a backup contraceptive on Amoxicillin? ▾
Backup contraception is needed only when there is a documented interaction between Amoxicillin and the contraceptive method. For most users at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, 1000/62.5mg, no backup is required. The pharmacist confirms whether Amoxicillin interacts with hormonal contraception.
Products containing Amoxicillin
More on Amoxicillin
- With alcoholAmoxicillin and alcohol — is it safe to drink?
- With foodShould Amoxicillin be taken with food?
- Side effectsAmoxicillin side effects: common, rare and warning signs
- Dosage guideAmoxicillin dosage guide: how much to take and when
- OnsetHow fast does Amoxicillin start working?
- DurationHow long does Amoxicillin last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.