Orlistat for the long-term treatment of obesity.

Orlistat, a potent gastrointestinal lipase inhibitor, is a member of a new class of drugs designed for the long-term treatment of obesity. When given with a fat-containing meal, orlistat reduces dietary fat absorption by approximately 30%, which equates to a decrease in caloric absorption of approximately 200 kilocalories per day. A 2-year European study found a mean decrease in body weight of 10.2% (10.3 kg) in the orlistat group compared to 6.1% (6.1 kg) in the placebo group at 1 year. Additionally, 9.3% of the orlistat group versus 2.1% of the placebo group lost >20% of their initial weight. Serum lipids and diabetes control are also improved by orlistat. Related to orlistat's mechanism of action, side effects include oily spotting, flatulence and frequent loose stools, but not frank diarrhea or intestinal malabsorption. Vitamin D and beta-carotene levels decreased, but remained within the normal range. In summary, orlistat is the first example of a new class of antiobesity drugs that enhances weight loss and weight maintenance by interfering with dietary fat absorption. Orlistat has tolerable gastrointestinal side effects and no major drug toxicity. Orlistat is a viable adjunct to lifestyle interventions used in the long-term management of obesity.