Aygestin 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 Aygestin (Norethindrone Acetate). The combination is generally fine at 5mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Aygestin 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 Norethindrone acts on CYP3A4 determines whether Aygestin affects contraception. Most agents in Women's Sexual Health have no clinically meaningful effect on the pill at 5mg.
Practical guidance
According to the prescribing information for Norethindrone, women on hormonal contraception should review Aygestin 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 Aygestin therapy is the standard mitigation.
Frequently asked questions
Will Aygestin make my pill less effective? ▾
Most Women's Sexual Health medications at 5mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Norethindrone states whether the interaction is meaningful.
Do I need a backup contraceptive on Aygestin? ▾
Backup contraception is needed only when there is a documented interaction between Aygestin and the contraceptive method. For most users at 5mg, no backup is required. The pharmacist confirms whether Norethindrone interacts with hormonal contraception.
More on Aygestin
- With alcoholAygestin and alcohol — is it safe to drink?
- With foodShould Aygestin be taken with food?
- Side effectsAygestin side effects: common, rare and warning signs
- Dosage guideAygestin dosage guide: how much to take and when
- OnsetHow fast does Aygestin start working?
- DurationHow long does Aygestin last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.