Safety review launched into anti-epileptic medicine topiramate over fears of harm to unborn children

The Medicines and Healthcare products Regulatory Agency (MHRA) has launched a review into the safety of topiramate after study results showed an increased risk of autism, developmental disorders and learning difficulties among babies exposed to the medicine during their mother’s pregnancy.

The review will consider whether additional measures are needed to reduce the risk of harm from topiramate use during pregnancy.

Topiramate, which is used for treatment of migraines as well as epilepsy has already been linked to congenital malformations and effects on prenatal growth following study results.

The new review was prompted by an observational study published in JAMA Neurology in May 2022, results of which showed there was a two- to four-fold increased risk of developmental disorders (such as autism spectrum disorder) or learning difficulties among children exposed to topiramate before birth.

The researchers, who studied records of 4.5 million children in Denmark, Finland, Iceland, Norway and Sweden, concluded: “Our results do not suggest that topiramate is a safe alternative to valproate.”

They also found that sodium valproate was linked to a similar level of risk as topiramate.

Topiramate safety was most recently reviewed by the Commission on Human Medicines in January 2021 as part of a review of all antiepileptic drugs.

At the time, prescribers were advised to “discuss with women the risks associated with anti-epileptic drugs and with untreated epilepsy during pregnancy and review their treatment according to their clinical condition and circumstance”.

A spokesperson for the charity Epilepsy Action welcomed the review into topiramate. “It is crucial that women do not stop taking their epilepsy medicines without talking to their doctor first,” they said.

“Anyone taking topiramate who is pregnant or planning a pregnancy, should contact their epilepsy specialist nurse or doctor for urgent advice about the safest medicine for them and their baby.”

The MHRA already advises against use of valproate for women of childbearing age, but NHS Digital data, published in April 2022, have revealed that almost 50 pregnant women were prescribed the drug in England between October 2020 and September 2021.

In June 2022, the MHRA asked the Commission on Human Medicines to look at whether the genetic changes triggered by valproate can be passed down through generations.