Belviq (locaserin HCL), an appetite suppressant that can help people lose weight and keep that weight from coming back for a few years, has hurdled a mandatory long-term federal study that allows it to keep being sold in the U.S.

This success means that pharmacies can keep dispensing this prescription drug, which was approved for use by the U.S. Food and Drug Administration (FDA) on June 27, 2012, and sold in the USA since 2013. Several previous studies also found Belviq effective for weight loss.

Belviq, which is manufactured by the Japanese pharmaceutical firm, Eisai Co Ltd, is the first of several new weight-loss medicines to succeed in the FDA's required long-term heart safety study. Belviq works by stimulating brain chemicals to give one a feeling of fullness.

Belviq isn't a wonder drug that will help one lose a lot of weight, however. Studies show the weight loss produced by Belviq is quite small. After 40 months of daily use, Belviq users lost only nine pounds or four kilograms.

This weight loss, however, was double that of study participants who took a placebo. This result still confirms the two best ways to lose weight and to keep that weight from returning is to diet and exercise religiously.

Researchers tested it on 12,000 people that were either obese or overweight with heart disease risk factors such as high blood pressure. These participants were given Belviq or placebos, or dummy pills, to take twice a day. Participants were offered lifestyle and diet advice.

At one year, 39 percent of the participants on Belviq and 17 percent on dummy pills lost at least five percent of their starting weight.  Six percent in each group suffered a heart-related problem or death after some three years. Fewer people on Belviq developed diabetes. The results were 8.5 percent for Bleviq versus 10.3 percent on placebo. Belviq costs from $220 to $290 a month in the United States.

Worldwide, 13 percent of adults are obese and 39 percent are overweight. Diet and exercise are recommended by doctors to people that want to lose weight. Medicines, however, can be considered for those with dangerously high weight, and who couldn't lose enough weight by other means.