Side Effects: What is Belviq?

Newly approved by the FDA – Belviq is a weight loss drug

Belviq targets a brain area that influences appetite, called the serotonin 2C receptor. It’s the same receptor targeted by fenfluramine, the “fen” component of the infamous 1990s diet drug combo fen-phen.

However, Belviq is considered safer because it’s more selective—specifically targeting serotonin receptors linked to hunger, using a different brain pathway than fen-phen did. The new diet pill curbs appetite by boosting feelings of fullness and satiety, so people eat less.

In three randomized clinical trials involving nearly 8,000 overweight and obese adults, those who took Belviq for up to one year, in combination with cutting calories and exercise, dropped an average of 3 to 3.7 percent of their body weight. For a 200-pound person, that would be a loss of 6 to 7.4 pounds.

About 47 percent of patients without diabetes shed at least 5 percent of their starting weight—enough to significantly reduce their risk for diabetes and other health problems—compared to only 23 percent of those treated with a placebo. About 38 percent of diabetic patients treated with Belviq and 16 percent of placebo users lost at least 5 percent of their body weight. Diabetics who took the drug also had beneficial changes in blood sugar control.

NOTE: The FDA advises people who haven’t lost at least 5 percent of their body weight after taking Belviq for 12 weeks to stop the drug, since further treatment is unlikely to help them slim down.

Belviq should only be used by overweight or obese people under a doctor’s supervision. Pregnant women should not use the new diet pill. People with heart failure should use it with caution, warns the FDA, due to preliminary evidence that it might have problematic effects.

The agency has ordered the drug’s manufacturer to conduct after-market studies to monitor people who use Belviq for any cardiovascular complications that might emerge with wider use of the new medication.