Anti-Obesity Drugs Linked to Psychiatric Side Effects

June 25, 2008

Acomplia (rimonabant), marketed as an aid to controlling obesity, is thought to block cannabinoid receptors in the brain. Such receptors reportedly stimulate hunger pangs in humans. The same receptors are said to be linked with emotional states. Rimonabant is presently sold in over 30 countries and was approved by the European Medical Agency in June 2006.

Sanofi-aventis submitted its NDA for Acomplia in 2005. In 2006, FDA asked for further data. Last year, because of fear of psychiatric side effects, FDA refused to allow Acomplia to be marketed in the U.S. FDA also questioned the drug’s efficacy, concluding that improvements reported from clinical trials were often modest. Recent reports from the U.K. have raised concerns that five deaths, including one suicide, may have been related to use of the drug there in 2006. The Medicines and Healthcare Products Regulatory Agency, the U.K.’s answer to the FDA, posted a report on its Web site recently describing adverse reactions allegedly arising from use of rimonabant over the previous two years. In some instances, more than one side effect was described; 2,100 such reactions were reported among 720 users. MHPR reported depression in as many as 10% of users. The report did not indicate that the drug necessarily caused the problems.

Acomplia carries a warning label about heightened risks for those with depression or taking anti-depressants. Ironically, other potential side effects include obesity and cardiovascular problems. Sanofi-aventis nevertheless wants to resubmit the drug under the name Zimulti for FDA approval in 2009. The drug may well turn out to be a great boon to the overweight. The traditional methods to combat obesity, however, such as diet and exercise, though they entail a greater need for self-discipline, could prove to be safer than many pharmacologic interventions.