Following a major safety review triggered by a new study conducted in Europe, the MHRA is introducing new safety measures for topiramate, also known by the brand name Topamax.
The Commission on Human Medicines (CHM) looked at findings from studies examining the risks associated with the use of topiramate during pregnancy, which showed that children born to mothers who take topiramate during pregnancy face a risk level approximately 2 to 3 times higher of intellectual disability, autism spectrum disorders and attention deficit hyperactivity disorder.
Following recommendations made by the CHM, the MHRA is now advising healthcare professionals that topiramate should not be prescribed to treat epilepsy during pregnancy unless there is no suitable alternative treatment. Topiramate should already not be used during pregnancy for migraine because of the known link with an increased risk of birth defects.
In order to fulfil the conditions of a Pregnancy Prevention Programme, women of childbearing potential must use effective birth control throughout treatment and take a pregnancy test prior to starting topiramate. Healthcare professionals should make patients aware of the risks of the use of this medication during pregnancy and therefore the completion of a risk awareness form is another requirement of this programme.
Patients are also advised that some birth control methods are less effective than others when using topiramate, and their GP or sexual healthcare practitioner will be able to help advise which birth control is right for them. Regular medication reviews, at least once annually, are also recommended. New safety and educational materials have been introduced for patients and healthcare professionals to support the implementation of these measures.
Topiramate is taken to prevent migraines or for the management of epilepsy and is thought to be prescribed to just over 30,000 female patients under the age of 55 in England in one month, according to the latest data from NHS England.
Prior to the start of the review, topiramate was already known to have risks associated with significant harm during pregnancy, including a higher risk of birth defects and low birth weight. For this reason, patients were previously advised against using it during pregnancy and to use highly effective contraception during treatment. The introduction of the Pregnancy Prevention Programme will further strengthen the safety measures and aim to reduce the number of topiramate-exposed pregnancies.
Pregnant women or those planning to become pregnant, who currently take topiramate for epilepsy, should not stop taking the medication prior to seeking advice from a specialist, as doing so may cause their seizures to start again, happen more often or last longer. If planning to conceive, women should make an appointment with their GP to discuss their treatment options.
In 2021 CHM concluded that, of the antiepileptic medicines reviewed for use in pregnancy, lamotrigine and levetiracetam are considered safer, since they were not associated with birth defects if used in pregnancy.
Other recommendations made by the CHM include updates to the topiramate product information leaflet, to fully reflect the available data on the risks of use during pregnancy.
A visual warning symbol will be added to the box of all topiramate medicines. This ‘no’ symbol will show a pregnant woman in a red circle with a line through it. This will be accompanied by warning text about the risks.
Suspected adverse drug reactions associated with topiramate, should continue to be reported to the Yellow Card scheme.