H2-receptor antagonist
Famotidine 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 Famotidine (Famotidine). The combination is generally fine at 10mg, 20mg, 40mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Famotidine 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 Famotidine acts on CYP3A4 determines whether Famotidine affects contraception. Most agents in H2-receptor antagonist have no clinically meaningful effect on the pill at 10mg, 20mg, 40mg.
Practical guidance
According to the prescribing information for Famotidine, women on hormonal contraception should review Famotidine 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 Famotidine therapy is the standard mitigation.
Frequently asked questions
Will Famotidine make my pill less effective? ▾
Most H2-receptor antagonist medications at 10mg, 20mg, 40mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Famotidine states whether the interaction is meaningful.
Do I need a backup contraceptive on Famotidine? ▾
Backup contraception is needed only when there is a documented interaction between Famotidine and the contraceptive method. For most users at 10mg, 20mg, 40mg, no backup is required. The pharmacist confirms whether Famotidine interacts with hormonal contraception.
Products containing Famotidine
More on Famotidine
- With alcoholFamotidine and alcohol — is it safe to drink?
- With foodShould Famotidine be taken with food?
- Side effectsFamotidine side effects: common, rare and warning signs
- Dosage guideFamotidine dosage guide: how much to take and when
- OnsetHow fast does Famotidine start working?
- DurationHow long does Famotidine last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.