"People need to understand that lifestyle modifications are essential for successful weight loss, weight maintenance, and fitness programs. The weight loss reported in the studies is modest and the placebo group lost weight too, indicating that ongoing lifestyle counseling and support have a positive impact with and without medication," she said.
There are some issues with the drug, the FDA said. First, Belviq should be stopped if patients don't lose at least 5 percent of their weight within 12 weeks, since they're unlikely to benefit from taking the drug for any longer period of time.
Second, the drug shouldn't be taken during pregnancy, the agency said.
Belviq may cause serious side effects, including "serotonin syndrome," particularly when taken with certain medicines that increase serotonin levels or activate serotonin receptors, such as drugs used to treat depression and migraine. The drug may also cause problems with attention or memory, the FDA said.
Other common side effects in non-diabetic patients include headache, dizziness, fatigue, nausea, dry mouth, and constipation. In diabetic patients, side effects can include low blood sugar, headache, back pain, cough, and fatigue, the FDA said.
The agency is requiring Arena to undertake six post-marketing studies to look for any problems with Belviq, particularly the risk for heart attack and stroke.
Another weight loss drug, Qnexa from Vivus Inc., is still awaiting FDA approval. An FDA advisory panel recommended approval in February.
For more on obesity, visit the U.S. National Library of Medicine.
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