Orlistat: A New Antiobesity Drug

Abstract

Obesity is increasingly being recognized as a chronic disease associated with significantmorbidity and mortality worldwide. Orlistat, the first lipase inhibitor, was recently introduced to the Thai market as well as other international markets. This pharmacological breakthrough compound may lead to a very promising future for obesity treatment in both initial and maintenance therapy. Fundamentally, orlistat acts as a reversible inhibitor of lipase by forming a covalent bond with lipase. Oral orlistatacts specifically on gastro-intestinal lipase to prevent dietary fat from being digested and diminishes fat absorption. The reduction of fat absorption leads to calorie deficits (compared to the same environment without orlistat) and may have a positive effect on weight management as well asserum cholesterol level and other risk factors including hypertension. Pre-clinical data of orlistat are veryencouraging. Several clinical trials have been conducted to prove both the efficacy and toxicity of the compound. Efficacy on potentiating weight reduction was demonstrated on several occasions. The most common side effects noticed were gastro-intestinal symptoms. As other new and chemicallybreakthrough compounds, long-term side effects and efficacy need to be monitored. In conclusion, orlistat has a unique mechanism of action and can be used as an effective adjunctive therapy in obesity management.