Modest weight loss observed in diet drugs

According to research published in the 16 November edition of the British Medical Journal (BMJ), the three currently marketed diet medications licensed for long-term use cause minimal weight loss, but do reduce other health risks associated with obesity.

The Canada- and Brazil-based researchers pooled existing data on Roche's Xenical (orlistat), Abbott Lab's Meridia (sibutramine) and sanofi-aventis' Acomplia (rimonabant).

The researchers looked at 16 studies that tested Xenical, which works by preventing fat digestion. It helped people lose about seven pounds on average, but it also reduced diabetes and improved cholesterol levels and blood pressure. Up to 30 per cent of patients had digestive and intestinal side effects.

In the 10 tests of Meridia, study participants lost on average nine pounds and exhibited improved cholesterol levels. Approximately 20 per cent suffered side-effects, including raised blood pressure and pulse rates, insomnia and nausea.

In the four Acomplia studies, scientists found that users lost on average about 11 pounds. The drug also improved their blood pressure and cholesterol levels. The risk of mood disorders increased in six per cent of patients. Both Meridia and Acomplia work by interrupting nerve signals in the brain.

Another study in the same issue of the BMJ showed that Acomplia raised the risk of psychiatric problems like depression and anxiety. The drug has been approved by the European Medicines Agency (EMEA), but was rejected by an FDA panel in June 2007 due to the psychiatric side effects. The authors added that the long-term effects of the all the examined drugs were not known.

Dr Raj Padwal, an assistant professor at the University of Alberta in Canada, a co-author of one of the studies, said: "Drugs are not the magic cure and are not for everybody. But in specific patients, they have great benefits."

FY06 global sales of the drugs were estimated at USD 1.2bn.