Antibiotics 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 Antibiotics (Antibiotics). The combination is generally fine at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Antibiotics 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, Azithromycin, Ciprofloxacin, Clavulanate, Doxycycline acts on CYP3A4 determines whether Antibiotics affects contraception. Most agents in Antibiotics have no clinically meaningful effect on the pill at 250mg, 500mg, 875mg, 500/125mg, 875/125mg.
Practical guidance
According to the prescribing information for Amoxicillin, Azithromycin, Ciprofloxacin, Clavulanate, Doxycycline, women on hormonal contraception should review Antibiotics 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 Antibiotics therapy is the standard mitigation.
Frequently asked questions
Will Antibiotics make my pill less effective? ▾
Most Antibiotics medications at 250mg, 500mg, 875mg, 500/125mg, 875/125mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Amoxicillin, Azithromycin, Ciprofloxacin, Clavulanate, Doxycycline states whether the interaction is meaningful.
Do I need a backup contraceptive on Antibiotics? ▾
Backup contraception is needed only when there is a documented interaction between Antibiotics and the contraceptive method. For most users at 250mg, 500mg, 875mg, 500/125mg, 875/125mg, no backup is required. The pharmacist confirms whether Amoxicillin, Azithromycin, Ciprofloxacin, Clavulanate, Doxycycline interacts with hormonal contraception.
Medications in Antibiotics
More on Antibiotics
- With alcoholAntibiotics and alcohol — is it safe to drink?
- With foodShould Antibiotics be taken with food?
- Side effectsAntibiotics side effects: common, rare and warning signs
- For older adultsAntibiotics after 60: doses and safety in older adults
- For womenAntibiotics for women: indications and considerations
- For menAntibiotics for men: indications and considerations
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.