New weight-loss pill shows promise

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PHOENIX – A new weight-loss pill that experts call promising could soon be up for approval by the Food and Drug Administration.

It’s called Qnexa and many believe it could be a breakthrough in the treatment of obesity.

Qnexa is a combination of Topomax, a medication for migraines, seizures and drug addiction, and phentermine, an amphetamine that has been widely used as a weight-loss drug for several years. Both drugs are already approved by the FDA for specific uses.

While Dr. Art Mollen still advocates diet and exercise as the best way to lose weight, he said the concept behind Qnexa is interesting.

A recent article in “Archives of General Psychiatry” suggested that patients who are extremely obese might not be getting the best results with diet and exercise alone. The piece suggested that overeating could be an additive behavior and should be treated as such. That’s where the Topomax comes in.

Qnexa is not the first obesity treatment to combine two drugs. The Fen-phen diet, popular in the ‘90s, combined fenfluramine and phentermine. Fen-phen was later linked to potentially deadly problems, including valvular heart disease and pulmonary hypertension. By 2004, Fen-phen was no longer widely available.

According to a study sponsored by the pharmaceutical company that makes Qnexa, the high-dose version of the drug resulted in an average weight loss of about 22 pounds over the course of a year. The loss reportedly is twice as large as that achieved with Orlistat, marketed as Xenical, the only approved long-term anti-obesity medication. Orlistat is available over the counter as Alli.

A low-dose version of Qnexa result in an 18-pound drop over the same time period. Those who took part in only a counseling program lost 3 pounds.

According to researchers, Qnexa also appeared to have a positive impact on obesity-related issues such as high blood pressure and high cholesterol.

The most common side effect reported by study participants were dry mouth, paresthesia (a feeling of "pins and needles"), constipation, insomnia, dizziness, and distorted taste.

Results of the Qnexa study was published online in the April 11 issues of The Lancet.

Mollen said Qnexa was refused FDA approval in October, but the manufacturers are hopeful that it will gain approval in the relatively near future. The rejection was issued because of a lack of data regarding the risk of birth defects and heart problems.

Some have expressed concerns about the side effects of Topomax. According to the manufacturer, the side effects are mild, but not everybody agrees.

“People who have been on Topomax are not real proponents of this particular drug by itself,” Mollen said. “When combined with an amphetamine, there may be some issues. The jury is still out.”

It’s not clear when California-based Vivus Inc. will resubmit Qnexa for FDA approval.