Contrave gets a nod from the Food and Drug Administration, becoming the third weight-loss pill to be approved in the United States in the last two years.

According to the FDA, Contrave was approved for use in chronic weight management alongside regular exercise and a lower-calorie diet. Made by Orexigen Therapeutics Inc., the weight-loss pill was designed to control cravings and reduce appetite, the same functions that previously-approved drugs Belviq and Qsymia offer.

Nearly 79 million of American adults are obese, according to the Centers for Disease Control and Prevention, and the condition amounted to $147 billion in medical costs back in 2008.

According to Jean-Marc Guettier, Division of Metabolism and Endocrinology director at the FDA's Center for Drug Evaluation and Research, Contrave offers another chronic weight management treatment option for those who are overweight or obese and have been diagnosed with at least one health condition that is weight-related, like hypertension or Type 2 diabetes.

Contrave is made up of a combination of bupropion and naltrexone. Bupropion is an antidepressant while naltrexone prevents opioid dependence which makes the drug more tolerable to patients.

Those prescribed to use Contrave must be evaluated after 12 weeks of use to assess if this line of weight-loss treatment is working. If the patient doesn't lose a minimum of 5 percent of their baseline body weight, Contrave is to be discontinued because it is no longer likely that more weight will be lost if the treatment is pursued.

The addition of Contrave to the roster of weight-loss pills officially distributed in the market is good news because it expands options for overweight and obese individuals but the sale of weight-loss medication isn't as brisk as expected. Given the number of people who could benefit from using a weight-loss pill, why aren't Belviq and Qsymia selling as they should?

One obstacle is the lack of long-term proof that the pills work in bringing about weight loss for patients. Individuals in need of treatment are also wary of using weight-loss pills because despite their benefits many fear the side effects they bring.

But even when a patient wants to use weight-loss pills, they are usually deterred by costs, most especially when health insurance providers and the government won't readily cover expenses incurred for obesity treatment. In fact, just 30 to 40 percent of health maintenance organizations offer obesity coverage. And whatever is covered is usually only a portion of the bill so patients still end up paying for bulk of the costs.

Contrave is also scheduled to enter the UK market in 2015.