Study Examines Topamax Side Effects

Baton Rouge, LAA new study involving topiramate (Topamax) compared the risk of Topamax side effects to those of valproate (Depakote) and found that the risk of certain topiramate side effects was lower than the risk of valproate side effects. Although those findings might be of some comfort to women taking Topamax, other studies published this year point to an increased risk of Topamax side effects in children when a pregnant woman takes the drug.

The study comparing topiramate to valproate is set to appear in the Journal of Clinical Neuroscience (the study is not yet published but the proof is online, 5/11/13). In it, researchers found that of patients with juvenile myoclonic epilepsy (JME) had similar levels of success in treatment rates. Despite the sample size being small - 16 patients were given topiramate and 17 were given valproate - researchers concluded that both drugs were similar in their effectiveness.

They also found, however, that patients suffered fewer side effects when taking topiramate. Researchers noted that only one out of 10 (10 percent) adverse events linked to topiramate was rated moderate to severe, as compared with 10 of 17 (59 percent) adverse effects linked to valproate. This led researchers to conclude that patients who do not tolerate valproate could be switched to topiramate.

Both topiramate and valproate have been linked to birth defects when pregnant women have taken the drugs. A study published in the journal Acta Neurolgica Scandinavica (3/6/13) suggested a link between the use of topiramate while pregnant and certain birth defects. Specifically, researchers found a link between the anti-seizure medication and the development of hypospadias and “brain maldevelopments.” Researchers concluded that more extensive data was needed to confirm the findings.

In 2011, the US Food and Drug Administration (FDA; 3/4/11) issued a warning that topiramate could increase the risk of cleft lip and/or cleft palate in infants who were exposed to the medication prior to birth. At the time, the FDA noted that the risks and benefits of the medication should be carefully weighed when prescribed to women of childbearing age, especially when prescribed to treat conditions that are not life threatening, such as migraines.

The FDA’s warning came after data from the North American Antiepileptic Drug (NAAED) Pregnancy Registry suggested an oral cleft prevalence of 1.4 percent in infants exposed to topiramate during the first trimester, as compared with 0.38 percent to 0.55 percent in infants who were exposed to other antiepileptic drugs and 0.07 percent in infants whose mothers did not take antiepileptic drugs.