Study Finds Common Overlap Between Epilepsy Drugs and Hormonal Birth Control

Overview

• Researchers using U.S. Medicaid claims data published Oct. 7–8, 2026 identified 110,976 people with epilepsy of childbearing potential taking antiseizure medications and found nearly one in five received a hormonal contraceptive vulnerable to interaction.
• Among the 21,923 people prescribed a susceptible contraceptive, 7,154 (32.6%) had at least one overlap of 14 days or longer with enzyme-inducing antiseizure medications, with a median concurrent duration of 218 days.
• Enzyme-inducing antiseizure drugs named in the study include carbamazepine, oxcarbazepine, phenobarbital, phenytoin and topiramate, while affected contraceptives include combined and progestin-only pills, patches, rings and implants.
• The study did not measure actual contraceptive failure or pregnancy outcomes and cannot confirm whether patients took medicines as prescribed, so authors stress the need for outcome studies and investigation into why these combinations are prescribed.
• Clinicians and institutions are urged to improve shared decision-making by discussing unaffected options such as copper or hormonal intrauterine devices, using medication review tools and considering electronic alerts or pharmacist checks to reduce risk.