Two-thirds of U.S. adults are overweight and a third are obese, but few diet drugs have been able to make a dent in what is rapidly becoming our "gross national product." Diet drugs have 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 The popular Fen Phen was withdrawn almost fifteen years ago for killing at least 120 people. Meridia, another popular diet drug, was withdrawn in 2010 for increasing the incidence of cardiovascular events in patients.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 diet 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." Comics had a lot of fun with them when they were first approved with lines like "With Allies Like This, Who Needs Enemas?" and "Free coupon for Depends."
In 2010, the FDA 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 topiramate, an epilepsy drug patented as Topamax, and phentermine, the phen in Fen Phen.
Next week the FDA will reconsider Qnexa. Two years ago, an FDA advisory committee heard patient Erin Aycock testify that she lost 50 pounds on Qnexa. Others patients, on the drug-rating site askapatient.com, say they lost 10 percent of their body weight on Topamax but also sometimes lost their memory and hair too. Oops. (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.) Qnexa's weight loss properties may stem from topiramate's penchant for making food and beverages tastes bad, a side effect scores of users on askapatient cite. In 2009, the drug also received an FDA suicide warning (along with other seizure drugs) and in 2011, it received a warning that it may cause birth defects.
And phentermine the other drug in Qnexa? "I honestly can't distinguish this drug from Adderall, or even cocaine," says one phentermine user. "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.
After hearing testimony in 2010, the FDA advisory committee voted ten to six against approving Qnexa because of concerns about depression, memory loss, birth defects and lack of long term data. Since then, both the drug's safety profile and national obesity have worsened. Will opinions have changed given that both the drug's good and bad features sound a lot like Fen Phen's?