ORLANDO, Fla.—Because of medication interactions, risks for abuse and the teratogenic effects of anti-seizure drugs, adolescents with epilepsy who become pregnant have a unique risk profile that should be addressed by their neurology care team, said Sarah Weatherspoon, MD, a pediatric epileptologist at Le Bonheur Children’s Hospital, in Memphis, Tenn., at the 2023 annual meeting of the American Epilepsy Society.

Despite decreases, unplanned teen pregnancy still constitutes a national health problem that disproportionately affects poor and minority patients, she said.

Although neurologists and pharmacists may be hesitant to initiate conversations around puberty, sexual activity and the risk for unplanned pregnancy, the reality is that epileptic patients often interact with their neurology care team more frequently than with their primary care provider or gynecologist, Dr. Weatherspoon said. So, it falls to the neurology care team to have these conversations and help patients with epilepsy understand their options for reliable contraception.

Drug interactions can reduce the efficacy of both the birth control and anti-seizure medications, she said. Certain anti-seizure medications, including carbamazepine, phenytoin and topiramate, render some forms of hormonal birth control less effective via enzyme induction. Increased activity of the cytochrome P450 system increases estrogen metabolism in the liver causing subtherapeutic concentrations, contraceptive failure and potential unintended pregnancy. Meanwhile, the estrogen from hormonal birth control can decrease the effectiveness of medications like lamotrigine and reduce the concentration by as much as 50%. In this case, a concomitant dose increase is required to maintain therapeutic levels, according to the American College of Obstetricians and Gynecologists (ACOG) guidelines.

An intrauterine device is often the simplest and most effective contraceptive for young patients with seizures, with a potential failure rate of less than 1%, Dr. Weatherspoon said. Depot medroxyprogesterone acetate (DPMA) injections every 10 to 12 weeks are also an option because they are not affected by enzyme-inducing drugs. Studies have also reported a reduction in seizure frequency with DPMA, according to ACOG. However, this must be balanced with the risk for lowered bone mineral density in a patient population already at risk for this, according to Dr. Weatherspoon.

Neurologists and pharmacists should prepare patients and families for these decisions before puberty, she urged. “Thirteen is too late to start these conversations,” she said. The risk for abuse is three to four times higher in patients with an intellectual disability, and many patients with epilepsy have a disability, she explained.

“Many medications used to treat epilepsy also increase the risk of teratogenicity if a patient does become pregnant. So, early conversations and working with a multidisciplinary network of providers are the best ways to protect patients and prevent unplanned pregnancies,” she said.

 

Source: pharmacypracticenews.com, Donavyn Coffey

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