So How Does it Work?

The story of rimonabant begins, not in a laboratory, but in student bedrooms, hippie communes and the more relaxed type of cafeteria. It begins with cannabis2. As anyone who has ever used cannabis will know, a common side effect is ‘the munchies’ - a craving for food. Research in animals showed that this effect is largely the result of the effects of cannabis on proteins called ‘endocannabinoid (EC) receptors’ in the brain. Cannabis stimulates these receptors, leading to the feelings of hunger. So, if activating the receptors makes you hungry, perhaps blocking the same receptors can stop you feeling hungry…

Rimonabant acts by blocking a particular type of EC receptor (EC1) that is found in the brain, as well as in other tissues involved in appetite and metabolism, including adipose (fat) tissue, liver, muscle and the digestive tract. Further studies in rodents fed a high-fat diet showed that blocking EC1 receptors caused animals to lose weight, and also had beneficial effects to reduce levels of the so-called ‘bad’ cholesterol3 without affecting levels of ‘good’ cholesterol4, and to improve glucose and insulin levels. A further effect of rimonabant was to increase levels of the hormone adiponectin. This hormone, which is decreased in obese people and animals, is believed to be involved in the prevention of atherosclerosis - the process that leads to blocking of arteries.