Side Effects Hamper Diet Pill Approval - TheStreet

The effectiveness of a certain weight loss drug isn’t good enough to outweigh serious side effects, including depression and memory loss, according to an FDA advisory panel.

People who took a high dose of the experimental drug Qnexa lost an average of 10.6% of their weight after a year, according to the results of a recent study. However, participants in both high and moderate dosage groups saw worse memory loss than those who took a low dose of the drug. Low and moderate doses didn’t yield high weight loss benefits.

Many of those who took moderate and high doses dropped out of the program due to negative effects of the drug, the FDA reported. About 17.4% or 276 people who were on the high dose dropped out and 11.6% or 58 patients on moderate dose dropped out due to negative side effects.

“Most side effects were mild to moderate in severity, manageable and reversible,” however, FDA briefing documents noted.

Qnexa is a combination of two medicines already on the market: phentermine, a popular weight loss drug that was prescribed 6.1 million times last year alone, and topiramate, which is currently used to treat seizure disorders and prevent migraine headaches. About 9 million prescriptions were written in 2009 for topiramate, according to an FDA advisory committee, the group that decided against recommending the combined product for use in conjunction with diet and exercise. According to the FDA, topiramate was already known to lead to weight loss and memory loss.

Qnexa isn’t dead in the water quite yet. The drug could still be approved by the FDA, although the agency tends to follow the recommendations of its advisory panels.

Many unsuccessful dieters have been willing to put up with some negative drug side effects in the name of losing weight, however. Alli, a commonly-used weight loss option, is known to cause potentially embarrassing bathroom emergencies.

The American market for weight loss products currently stands at about $58 billion, according to