Despite Risk of Birth Defects from Topiramate, FDA Panel Approves Diet Drug

An FDA panel of outside advisors has given the nod to a new weight loss drug developed by Vivus, Inc., which was was previously rejected due to concerns over the risk of birth defects from topiramate, such as cleft lip, cleft palate and other malformations when the medication is used during pregnancy. 

The proposed weight loss pill, Qnexa, is a combination of phentermine, an amphetamine, and topiramate, an antiseizure drug that is the active ingredient in Topamax.

The FDA has rejected the drug once before, but an advisory panel voted 20-2 this week to recommend that the agency now approve the drug, saying that its weight loss effects could reap huge health benefits that justify the potential risks. If approved, it would be the first new FDA-approved weight loss drug on the market in over a decade.

In 2010, the FDA rejected Qnexa because of the risk of numerous side effects, including birth defects, psychiatric effects and potential heart problems.

Concerns over the potential topiramate birth defect risks increased following a 2008 study that found 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.

As part of the review process, the FDA asked Vivus to assess how often pregnant mothers treated with topiramate from use of the epilepsy drug Topamax had children with cleft palate or lips.

In March 2011, the FDA issued a warning that Topamax side effects may increase the risk of oral cleft birth defects among babies born to mothers who took the drug during the first trimester of pregnancy. As a result, the FDA has urged doctors to avoid giving Topamax to pregnant women or women who are of child-bearing age and at a high risk of pregnancy.

A number of families are now pursuing a Topamax lawsuit against the manufacturer of that medication, alleging that they failed to adequately research the medication or warn about the risk of using topiramate during pregnancy.

Cleft palate and cleft lip 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 can cause problems eating and talking and can increase the risk of ear infections, resulting in the need for corrective surgery.

Side effects of Qnexa may also increase the heart rate and heart palpitations, and it remains unclear what impact those risks will have on the heart. The phentermine component of the weight-loss drug was used as part of the recalled weight loss drug Fen-Phen.

Despite the known risks, the FDA advisory panel concluded this week that the benefits of the medication outweigh the potential side effects. With obesity reaching 35% of all adults in the United States, the panel suggested that there is a need for the drug, which appears to help an adult lose 10% of their body weight over one year.

Although the FDA is not required to follow the recommendations of its advisory panels, they often factor heavily into the agency’s final decisions. A final decision on Qnexa is expected by April 17.