Topiramate, brand name Topamax, is a common anti-seizure medication that is also taken by some migraine patients. Though many similar drugs also increase the risk of birth defects, the incidence of birth defects seen when Topamax was taken with other anti-epileptic drugs was higher than expected.
John Craig, of the Royal Group of Hospitals in Belfast, Northern Ireland, collected data on 203 women who became pregnant while taking topiramate alone or with other epilepsy drugs. The results indicated that of the 178 babies born, 16 (4.8 percent) suffered from major birth defects.
Four of the babies had cleft palettes or cleft lips while among male babies four had genital defects, with two classified as "major defects." Three of the mothers were taking topiramate exclusively, while 13 were taking topiramate plus other epilepsy drugs.
The rate at which the birth defects occurred were 11 to 14 times higher than one would expect among women not taking the drug, the researchers said in a news release from the American Academy of Neurology.
Johnson and Johnson's Topamax used alone led to three major congenital malformations and five minor birth defects. However, if taken in combination with other epilepsy therapies, Topomax resulted in 13 major and 10 minor malformations.
Other combination epilepsy therapies include Sanofi-Aventis' Frisium, Sabril, Epilim or Depakine, Pfizer Inc.'s Zarontin, UCB SA's Keppra as well as generic drugs carbamazepine, phenobarbitral or phenytoin, Bloomberg news reported.
The highest increase in birth defects was noticed in women taking Topamax along with the drug valproate. Valproate is sold as Depakote by Abbott Laboratories and as Depakine by Sanofi- Aventis.
Maintaining effective epilepsy treatment during pregnancy is crucial because seizures may cause harm to the fetus. Researchers suggest that those epileptic women who depend on this drug to control their convulsive seizures should continue it but if they are taking it for migraine prevention, the drug use should be discontinued before conception.
The report is published in the July 22 issue of the journal Neurology.
