Rimonabant 20 mg, combined with a hypocaloric diet over 1 year, promoted significant decrease of bodyweight and waist circumference, and improvement in cardiovascular risk factors.

Rimonabant ( Acomplia ) is a selective CB1 endocannabinoid receptor antagonist indicated for the treatment of obesity.
The drug works by blocking endogenous cannabinoid binding to neuronal CB1 receptors.
Activation of these receptors by endoegenous cannabinoids, such as anandamide, increases appetite.
Rimonabant also has potential as a treatment for smoking cessation because the endocannabinoid system is also involved in the body's response to tobacco dependence.

Luc Van Gaal from University Hospital Antwerp ( Belgium) and colleagues undertook a trial ( RIO-Europe ) involving 1507 people.

Participants had a body mass index ( BMI ) of 30 kg/m2 or greater, or a BMI greater than 27 kg/m2 with dyslipidaemia, hypertension, or both.
They were randomly assigned to receive 5mg or 20mg of Rimonabant, or a placebo once daily in addition to a mild hypocaloric diet.

The treatment groups had similar characteristics. 920 patients ( 61% ) completed the one-year follow-up; 379 in the Rimonabant 5mg group, 363 in the Rimonabant 20mg group and 178 in the placebo group.

Weight loss at 1 year was greater in patients treated with 5 mg or 20 mg of Rimonabant compared with placebo.

More than 67% of patients who completed treatment with 20mg of Rimonabant achieved 5% or more weight loss, and 39% achieved 10 % or more weight loss.

Patients on 20 mg of Rimonabant had greater improvements than placebo in waist circumference ( average reduction of 4 cm ), and cardiovascular risk factors including HDL cholesterol, triglycerides, insulin resistance and prevalence of metabolic syndrome.

The most common side effects leading to study discontinuation were depressed mood disorders in all treatment groups; withdrawls due to nausea, vomiting, diarrhoea, headache, dizziness, and anxiety were more frequent in the Rimonabant 20 mg group than in other groups.
Serious adverse events did not occur more frequently in patients treated with the drug than in those on placebo.

Source: The Lancet, 2005


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