Contrave is a weight loss drug produced by Orexigen Therapeutics, and is meant to treat obesity. Orexigen Therapeutics applied for FDA approval in late 2010, but the drug has not yet been approved for commercial release.

This approval for commercial release and prescription will still depend on the results of a large-scale, long-term study commissioned by the FDA as part of its recommendations for the drug’s approval.

FDA Investigation

The FDA wants to closely examine the cardiovascular effects of Contrave, since previously-released weight loss drugs have been shown to raise blood pressure and heart rate, which can put patients at risk for heart disease. For instance, Meridia was released as a weight loss supplement and was already available commercially. However, further studies showed that it could also put patients at risk for heart disease. Critics are afraid that Contrave is dead in the water, but such a large-scale, long-term study, although expensive, is actually precautionary and routine for many different drugs.

Clinical Trials

In clinical trials, Contrave was shown to slightly increase the blood pressure and pulse of patients who took the pill along with regular exercise and dieting. However, the same clinical trials also showed that patients were able to lose 5% of their weight when they took Contrave with a recommended dieting and exercise regimen compared with patients who had the same dieting and exercise regimen, but were taking a placebo.

Active Ingredients

Contrave contains two active ingredients: naltrexone and bupropion. Bupropion is speculated to be the active ingredient that puts patients at risk for heart disease. Naltrexone is already available on the market, and is used to treat addiction to alcohol and opioids. Bupropion is also commercially available, and is used to treat depression, as well as to help smokers quit their habit.

How It Works

According to the studies carried out by Orexigen Therapeutics, Bupropion should start the weight loss process, and naltrexone should sustain it over time. Together, these two drugs work to speed up and sustain weight loss by targeting vulnerable points in the body’s central nervous system. Contrave will reduce appetite and speed up the body’s metabolic rates. This dual effect can lower a person’s consumption of food, but can allow the person to rapidly and efficiently absorb nutrients from the food that is already available.

Contrave, moreover, acts on the centers of the brain that associate food with rewards. Associating food with rewards can cause food cravings, and Contrave’s ability to stop this can also stop the body’s tendency to overeat as well as to find rewards in eating. Contrave also aims to stop the body’s natural tendency to stop the process of losing weight, which involves bloating or packing on even more pounds. This natural tendency to gain weight is a stress response, as the body packs on nutrients when it senses that starvation is occurring.


According to studies of previously-approved drugs that have the same mechanisms, Contrave might cause heart attacks or even death. However, these effects still remain to be proven, as Contrave undergoes a long-term clinical trial to investigate all its effects.