Topamax Birth Defect Warning Issued by FDA
Federal regulators are warning that the epilepsy drug Topamax, and its generic equivalents, may increase the risk of birth defects in newborns when taken by pregnant mothers.
The FDA Topamax birth defect drug safety communication, issued on Friday, warned that there was a particular risk of cleft lip and cleft palate birth defects associated with the drug.
The warning comes a little more than a month after Vivus, Inc. announced it had been asked by the FDA to review potential reports of Topamax oral cleft birth defects associated with children born to mothers who took Topamax while they were pregnant.
The FDA advised all women of childbearing age to be aware of the potential risk of birth defects from Topamax, since oral cleft birth defects usually occur in the first trimester of pregnancy, when many women do not yet know they are pregnant.
Cleft palate and cleft lip birth defects occur when parts of the lip or palate fail to completely fuse together. The defect results in the child being born with defects as small as a notched lip to extreme as an open groove that goes from the roof of the mouth to the nose. Cleft palate and cleft lip birth defects can cause problems eating and talking and can increase the risk of ear infections. Most oral cleft deformities can be corrected with surgery.
The FDA looked at data from the North American Antiepileptic Drug (AED) Pregnancy Registry and found that children whose mothers took Topamax while pregnant had a oral cleft birth defect rate of 1.4%, compared with a rate of 0.38% among the rest of the population, and a rate of 0.55% among infants whose mothers took other antiepileptic medications.
“Health care professionals should carefully consider the benefits and risks of [Topamax] when prescribing it to women of childbearing age,” warned Dr. Russell Katz, director of the Division of Neurology Products for the FDA’s Center for Drug Evaluation and Research. “Alternative medications that have a lower risk of birth defects should be considered.”
In 2008, a study published in the medical journal Neurology found that a higher-than-expected number of pregnant women treated with Topamax gave birth to babies with cleft lips, cleft palates, genital defects or other birth malformations. Although the study identifying a potential risk of birth defects from Topamax was small, only involving 178 babies, the rate of birth defects was 11 times higher than would be expected in the general population.
Topamax (topiramate) was first approved for treatment of epilepsy, which is a neurological disorder characterized by recurrent uncontrolled seizures. In 2004, the FDA approved Topamax for an additional use of treating severe headaches known as migraines. It is also used off-label by many doctors to treat bipolar disorder. Generic forms of the drug began to appear in 2006.
The FDA estimates that approximately 32.3 million prescriptions for Topamax or a generic equivalent were issued from January 2007 through December 2010. In many cases the drug is prescribed for off-label uses.