Rimonabant: Boom to ban

Abstract

Rapidly rising prevalence of obesity and health care cost of its complications necessities
need for highly efficacious and safe antiobesity drugs. As most old antiobesity drugs
had moderate efficacy, severe toxicity and some of them very costly. Rimonabant, CB1
receptor antagonist was introduced with high expectations. Rimonabant has multiple
beneficial effects, apart from significant weight loss it increases HDL and reduces
triglycerides, Hb A1C level, prevalence of metabolic syndrome. This wide spectrum of
effects helps in comprehensive management of obesity and associated complications.
Cost of rimonabant (generic Rs.5-8 per tablet) is also much lesser than the only other
commonly used antiobesity drug orlistat around Rs. 40 per tablet. During trials
rimonabant apart from nausea had neuropsychiatric side effects. EMEA approved
rimonabant in June 2006 with concern over its psychiatric side effects. In 2007 EMEA
contraindicated rimonabant in patients of depression or taking antidepressants. Further
analysis in 2008 concluded that the incidence of psychiatric side effects was higher in
clinical practice compared to controlled trials also few cases of suicide became a major
safety concern, finally leading to suspension of its sale by EMEA in Oct 2008. USFDA
never approved rimonabant over safety concerns, while India banned it shortly thereafter
as precautionary measure. Present paper deals with the various events during the rapid
rise and fall of rimonabant which was widely considered as blockbuster diet pill but was
suspended over serious neuropsychiatric side effects.