indication

For use in conjunction with diet and exercise for patients with a body mass index greater than 30 kg/m², or patients wih a BMI greater than 27 kg/m² with associated risk factors, such as type 2 diabetes or dyslipidaemia.

pharmacology

In the RIO-North America trial, 3040 patients were randomized to receive either placebo or one of two doses of rimonabant (5 mg or 20 mg per day). Patients taking 20 mg rimonabant had significant weigh loss, decrease in waist circumference, improved insulin sensitivity, and increases in HDL cholesterol, compared to patients on placebo.

mechanism of action

Rimonabant is a specific CB1 cannabinoid receptor antagonist. There is considerable evidence that the endocannabinoid (endogenous cannabinoid) system plays a significant role in appetitive drive and associated behaviours. It is therefore reasonable to hypothesize that the attenuation of the activity of this system would have therapeutic benefit in treating disorders that might have a component of excess appetitive drive or over-activity of the endocannabinoid system, such as obesity, ethanol and other drug abuse, and a variety of central nervous system and other disorders.

toxicity

Almost twice as many people discontinued rimonabant compared with placebo because of adverse events (13.8% vs. 7.2%). These consistently involved psychiatric disorders (8.5% vs. 3.2%), including depression and anxiety. Other common side effects included insomnia, nausea, vomiting, diarrhoea and fatigue.

biotransformation

Hepatic, CYP3A4 involved.

absorption

Undetermined

half life

6 to 9 days with normal BMI and 16 days if BMI is greater than 30