Antiepileptic (sodium channel blocker)
Lamotrigine 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 Lamotrigine (Lamotrigine). The combination is generally fine at 25mg, 50mg, 100mg, 200mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Lamotrigine 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 Lamotrigine acts on CYP3A4 determines whether Lamotrigine affects contraception. Most agents in Antiepileptic (sodium channel blocker) have no clinically meaningful effect on the pill at 25mg, 50mg, 100mg, 200mg.
Practical guidance
According to the prescribing information for Lamotrigine, women on hormonal contraception should review Lamotrigine 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 Lamotrigine therapy is the standard mitigation.
Frequently asked questions
Will Lamotrigine make my pill less effective? ▾
Most Antiepileptic (sodium channel blocker) medications at 25mg, 50mg, 100mg, 200mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Lamotrigine states whether the interaction is meaningful.
Do I need a backup contraceptive on Lamotrigine? ▾
Backup contraception is needed only when there is a documented interaction between Lamotrigine and the contraceptive method. For most users at 25mg, 50mg, 100mg, 200mg, no backup is required. The pharmacist confirms whether Lamotrigine interacts with hormonal contraception.
Products containing Lamotrigine
More on Lamotrigine
- With alcoholLamotrigine and alcohol — is it safe to drink?
- With foodShould Lamotrigine be taken with food?
- Side effectsLamotrigine side effects: common, rare and warning signs
- Dosage guideLamotrigine dosage guide: how much to take and when
- OnsetHow fast does Lamotrigine start working?
- DurationHow long does Lamotrigine last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.