Rimonabant, discovered and developed by French pharmaceutical company Sanofi-Synthelabo (now Sanofi-Aventis) and marketed in Europe as Acomplia, is a new drug currently that has shown considerable promise in trials for the treatment of obesity and related metabolic risk factors.

Acomplia works by blocking the CB1 receptor, one of two receptors found in a newly described physiological system called the Endocannabinoid System, believed to play a critical role in the regulation of food intake and energy expenditure.

The receptors are present on the surfaces of many cells throughout the body, including fat cells -- which are involved in lipid and glucose metabolism -- and those in the hypothalamus, the brain region that is thought to determine appetite.

Cannabinoids, chemical compounds produced by your body, latch on to the CB1 receptors, which are overactive in overweight and obese individuals, sending out a signal that prompts people to eat more. 

Acomplia works by selectively targeting and blocking the CB1 receptors, helping normalize the over-activation of the EC system and making hunger or cigarette pangs more manageable.

This blocking of signals that control cravings appears to result in weight loss, improvement of cardiovascular/ metabolic risk factors in overweight/obese patients and appears to reduce tobacco dependence without post cessation weight gain in people who smoke.