Should The FDA Approve The Diet Drug Qnexa?

By Martha Rosenberg

Two-thirds of U.S. adults are overweight and a third are obese, but few drugs have been able to make a dent in our "gross national product." They've proved ineffective or dangerous or ineffective AND dangerous. The popular Fen Phen was withdrawn almost fifteen years ago for killing at least 120 people. Meridia, another popular diet drug, was withdrawn in 2010 for increasing the incidence of cardiovascular events in patients.

Other drugs remain on the market but have unpleasant side effects. Alli and Xenical encourage weight loss by blocking the body's absorption of fat but can cause "oily bowels" and "anal leakage." "With Allies Like This, Who Needs Enemas?" and "Free coupon for Depends" said comics when they were first approved.

In 2010, the FDA considered but failed to approve three diet drug candidates: Contrave, a drug that includes Wellbutrin, an antidepressant that lacks the weight gain side effects associated with other antidepressants; Lorcaserin, which also includes an antidepressant-like drug; and Qnexa, which combines the active ingredient in Topamax, an anti-seizure drug also given for pain and bipolar disorder, with phentermine (the "phen" in Fen Phen).

Recently, an FDA advisory committee reconsidered Qnexa after failing to recommend it in 2010 because of concerns about depression, memory-loss, birth defects and lack of long term data.

Few dispute that the drug combo can help people lose weight. During 2010 hearings, the committee heard patient Erin Aycock testify that she lost 50 pounds on Qnexa and other patients say they lost 10 percent of their body weight. Patients on the drug-rating site askapatient.com agree that both ingredients in Qnexa cause weight loss, even individually.

Topamax, the brand name for one of the two active ingredients in Qnexa, definitely causes weight loss, report drug raters on the site, but also memory and hair loss. (In fact Topamax' tendency to dumb people down is so well known it is referred to as "Stupamax" in the military where it is in wide use, says Army Times.) Topamax's weight loss properties may come from the fact that it makes food and beverages tastes bad say 33 users on askapatient. In 2009, it received an FDA suicide warning, along with other seizure drugs, and also has a warning for acute myopia associated with a type of glaucoma.

And the other active ingredient in Qnexa- phentermine? "I honestly can't distinguish this drug from Adderall, or even cocaine," says one phentermine user who rated the drug. "It might as well be called Prescription Coke." Users report losing 50 and 60 pounds on phentermine, though many say they gained it back. Phentermine users also report being unable to sleep and chewing the insides of their cheeks as if they were chewing gum-a frequent side effect of "speed." Phentermine is the half of Fen Phen that remains on the market.

Even though the FDA advisory committee failed to recommend Qnexa the first time around, US obesity has likely increased and obesity presents its own set of health risks. Many expect an FDA reversal on Qnexa with approval in the months ahead.

Martha Rosenberg's first book, Born With a Junk Food Deficiency: How Flaks, Quacks, and Hacks Pimp the Public Health, will be published in April by Prometheus Books.

Martha Rosenberg is a columnist and cartoonist, who writes about public health Read more stories by Martha Rosenberg.