Epilepsy Drugs May Interact With Hormonal Contraceptives

Key points:

• Nearly one-third of people with epilepsy in a new study had overlapping prescriptions for certain hormonal contraceptives and enzyme-inducing antiseizure medications.
• The overlap may reduce the effectiveness of some hormonal birth control methods.
• Clinicians should consider medication interactions when discussing contraception and pregnancy planning with patients with epilepsy.
• For More Updates in Neurology, register for American Neurology Summit 2026 (ANS2026)

Which epilepsy drugs may affect hormonal contraceptives?

Epilepsy drugs that induce liver enzymes may increase the breakdown of hormones used in certain contraceptives, potentially reducing their effectiveness. A study published October 7, 2026, in Neurology®, the medical journal of the American Academy of Neurology, examined how often these prescriptions overlapped among people with epilepsy.

Researchers reviewed medical records from 21,923 people with epilepsy who received hormonal contraceptives that can be affected by medication interactions and were also prescribed enzyme-inducing antiseizure medications. The contraceptive methods included combined oral contraceptive pills, progestin-only pills, patches, vaginal rings, and subdermal implants.

The antiseizure medications included carbamazepine, oxcarbazepine, phenobarbital, phenytoin, and topiramate, among others. These medication interactions are clinically relevant because reduced contraceptive effectiveness may increase the risk of unintended pregnancy.

How common is the overlap between antiseizure medications and birth control?

Among the study population, 7,154 people, or 32.6%, had at least one period lasting 14 days or longer when a hormonal contraceptive and an enzyme-inducing antiseizure medication overlapped. The average overlap lasted approximately seven months.

The findings highlight a potential gap in medication management for people with epilepsy who use hormonal contraception. Pregnancy planning can carry additional importance in epilepsy because pregnancy may involve increased health risks, while some antiseizure medications have been associated with risks to a developing fetus.

An unplanned pregnancy may also limit the opportunity to review antiseizure treatment and begin folic acid supplementation before conception.

What should clinicians consider when counseling patients with epilepsy?

The findings support careful contraceptive counseling and medication review for patients with epilepsy who use or are considering hormonal birth control. However, the study does not establish that contraceptive failure occurred.

Researchers did not evaluate pregnancy outcomes or determine whether participants experienced unintended pregnancies. Prescription records also cannot confirm whether patients took their medications as prescribed.

Importantly, not all contraceptive methods are affected by these medication interactions. Clinicians can use shared decision-making to consider a patient’s treatment regimen, contraceptive preferences, reproductive plans, and overall health needs.

For More Updates in Neurology, register for American Neurology Summit 2026 (ANS2026)

For neurologists, nurses, primary care clinicians, women’s health professionals, and other HCPs, reviewing potential drug interactions can be an important part of reproductive health counseling for patients receiving antiseizure therapy. Further research is needed to determine the real-world impact of these overlapping prescriptions on contraceptive failure and pregnancy outcomes.

Source:

American Academy of Neurology