New Diet Drugs Slug it Out on the Prescription Market -What’s the Difference?
For the first time in 13 years, the FDA has approved two new prescription diet drugs Belviq, manufactured by Arena Pharmaceuticals, and Qsymia, from Vivus Pharmaceuticals. While both drugs are designed for weight loss, they are by no means the same.
What is Qysymia?
Qysymia is a combination of two drugs. One is the appetite suppressant phentermine, which was part of the notorious fen-phen drug that caused heart valve problems twenty years ago…but phentermine was the safe part of the combination. Scientists aren’t exactly sure how phentermine works, but the prevailing hypothesis is that it suppresses appetite by flooding the brain with norepinephrine, which in turn triggers leptin production, a hormone that suppresses the appetite.
Topiramate, a drug previously approved for seizures and migraines, makes up the rest of the combination. It works in several ways, by increasing satiety, affecting taste sensitivity so foods are less appealing, and increasing thermogenic activity for more efficient calorie burning.
What is Belviq?
Belviq works by stimulating serotonin, the “feel good” chemical in the brain – the same chemical production affected by hallucinogens, like LSD, only not as intense. As long as it’s not abused.
The potential for abuse is apparent. Qsymia is already scheduled as a controlled substance, and Belviq is likely to be.
Which drug is more effective?
The drugs have not been compared in a head-to-head study, and neither had earth-shattering results in clinical trials. Weight loss with both drugs was gradual. Over the course of one to two years, Belviq study participants lost 3% to 3.7% more than participants taking placebos.
Study participants taking Qsymia for one year or less lost an average of 8.9% more than participants assigned to placebos. Of those who took Qsymia, 70% lost at least 5% of their total body weight over the course of the study.
The bottom line
In both cases, clinical trial participants were on a balanced diet and expected to exercise. In the case of Qsymia, 20% of the people taking placebos lost comparable to people given the drug.
I can’t help but wonder whether people taking the drug felt more positive, more accomplished, more energetic, and more motivated, and whether the people taking the placebo experienced the same feelings. Losing weight is terribly discouraging for significantly overweight people, so if the drugs affect nothing but hope, and there are no deadly side effects, it could be a good thing. But what happens if we find out down the line that, similar to the Fen-Phen fiasco, these new diet drugs come with significant health risks? Do the potential risks outweigh the benefits?