Study: Topamax Linked to Birth Defects

A new study suggests that taking Topamax during pregnancy could lead to side effects that include birth defects.

The study, conducted by researchers at the Royal Melbourne Hospital and University of Melbourne, Australia, looked at Topamax, Depakote (valproate), and Tegretol (carbamazepine) to understand the link between the use of these anti-epileptic medications during pregnancy and increased risks for birth defects, said Lawyers and Settlements. The study appears in the March 6, 2013 issue of the journal Acta Neurologica Scandinavica.

The researchers reviewed data from 1,733 fetuses from 1,703 pregnancies; 147 were not exposed to any anti-epileptic drug during pregnancy, said Lawyers and Settlements. The study goal was to determine if a link exists between fetal malformations and antiepileptic drug use during pregnancy. The study revealed a statistically significant link between Topamax use during pregnancy and increased risks for giving birth to a baby born with hypospadias and so-called brain “maldevelopments,” said Lawyers and Settlements. In hypospadias, the urethra’s opening is formed on the underside of the infant’s penis.

The researchers recommended additional research, specifically into Tomamax, as that drug is being used more and more in the prevention of migraines in women, Lawyers and Settlements noted. Topamax is generally prescribed to treat certain types of seizures and is also a migraine prevention treatment.

Prior studies have linked Topamax and other anti-seizure drugs to birth defects in babies exposed to the medications in utero; however, not all anti-seizure drugs have been linked to the same birth defects, Lawyers and Settlements pointed out.

North American Antiepileptic Drug (AED) Pregnancy Registry data suggested babies exposed to Topamax during pregnancy experienced a 1.4 percent likelihood of being born with oral clefts. This was in comparison to infants exposed to other anti-epileptic drugs who had a 0.38-0.55 percent prevalence and infants who were not exposed to any anti-epileptic and who had a 0.07 percent prevalence for this birth defect, Lawyers and Settlements wrote. The findings prompted the U.S. Food and Drug Administration to issue a warning in 2011 about the potential link between Topamax and oral cleft, which includes cleft lip and/or cleft palate. At that time, the FDA pointed out that the risk/benefit profile of Topamax should be carefully weighed, especially when prescribed for non-life-threatening conditions, said Lawyers and Settlements. Also at that time, the agency re-classified topiramate from Pregnancy Category C to Pregnancy Category D, which means evidence of fetal risk based on human data exists.

As we’ve reported previously, other birth defects may also be associated with Topamax. In fact, the FDA’s Adverse Event Report database has received scores of reports of injuries to children believed to be associated with the use of Topamax. Many involve possible Topamax birth defects, including oral clefts, limb malformations, heart defects, cranio-facial defects, spina bifida/spinal malformations, and persistent pulmonary hypertension of the newborn (PPHN).

Also, the American Headache Society has said that women of childbearing age should be careful about using Topamax to treat migraine headaches because of its birth defect risk. The same group has also warned that Topamax can impact the efficacy of certain contraceptives that contain estrogen. As such, women should discuss with their physicians alternative options for contraception while on Topamax to avoid unplanned pregnancies.

The FDA estimates that approximately 32.3 million prescriptions for Topamax, or a generic equivalent, were issued from January 2007 through December 2010.

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