Belviq, the new miracle diet drug? Fat chance.

This post has been corrected, as indicated below.

A new diet drug went on the market Tuesday. It’s expensive and has to be taken the rest of the patient’s life to continue to work. It comes with a long list of possible side effects, including common ones such as dizziness, fatigue and constipation, or rare ones such as hallucinations or memory loss. On average, it doesn’t have much effect on a person’s weight.

So what is there to love about Belviq? Doctors have been clamoring for another “tool” they can use in the fight against obesity, and if Belviq, which suppresses appetite, is only a lightweight hammer of a tool, even those are of use to some people. In a study, the average weight loss over the course of a year using Belviq was 3.7% more of a person’s total body weight than the patients on placebo. That’s very small: less than 10 pounds lost by a 250-pound person. That sort of loss could be easily achieved by mild changes in eating and exercise habits. But some people experienced greater weight loss and no side effects. For them, it could be worth the price.

And price is not a minor issue. Belviq reportedly is sold wholesale to pharmacies for $200 a month (it’s unclear how much of that will be covered by insurance) and, according to the U.S. Food and Drug Administration, patients who start on it need to take it for life — or as long as they want the pounds to stay off. Without Belviq, the appetite and the weight return.


This all might be worthwhile for the person who gets a considerably better-than-average weight loss (47% of patients in the trial lost at least 5% of their weight), but diet drugs have a history of long-term disappointment, as a roundup by ABC News shows. Fenfluramine (part of the fenphen combo) and Meridia were pulled from the market after the risks were found to outweigh the benefits. Orlistat -- better known by its over-the-counter brand name Alli -- never caught on big with consumers because of its unappetizing side effects.

Any truly long-term side effects of Belviq are unknowable right now, though it is by its nature a very long-term pharmaceutical. Obesity and appetite are complex problems that the simplicity of a pill has yet to crack. Perhaps the high price of Belviq will prevent off-label prescribing by doctors and overuse by people trying desperately to lose weight, and perhaps it will provide significant help to some, though certainly not most, people. But so far, the lesson from the land of pharmaceuticals is that they are not the solution to this nation’s obesity problem.

[For the record, 3:15 p.m., June 12: A previous version of this post said the average weight loss over the course of a year using Belviq was 3% to 3.7% of a person’s total weight. Actually, it was 3.7% more of a person’s total body weight compared to the patients on placebo.]


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