Epilepsy medications may reduce effectiveness of hormonal contraceptives

A study published in the medical journal Neurology indicates that certain antiseizure medications may reduce the effectiveness of hormonal contraceptives in people with epilepsy. Researchers analyzed treatments for over 21,000 individuals and found that approximately 32.6% of the group experienced periods where they used both a susceptible hormonal contraceptive and an antiseizure medication capable of reducing its efficacy.

The interaction occurs because certain medications, such as carbamazepine, oxcarbazepine, phenobarbital, phenytoin, and topiramate, can induce liver enzymes that accelerate the metabolism of hormones. This affects various contraceptive methods, including combined pills, progestin-only pills, patches, vaginal rings, and subcutaneous implants.

Dr. Laura Kirkpatrick of the University of Pittsburgh School of Medicine noted that these findings are concerning because unplanned pregnancies can pose additional health risks to both the parent and the developing baby. The study emphasizes the importance of informed contraceptive counseling and careful pregnancy planning for patients managing epilepsy.