Currently, the only centrally acting appetite suppressants on the market for obesity treatment are phentermine and diethylpropion, both of which are sympathomimetics with potential cardiovascular side effects. Orlistat, a peripherally acting agent, is a pancreatic and gastric lipase inhibitor that blocks 25% to 30% of fat calories from absorption in the gastrointestinal tract. Its actions are considered mild compared with appetite suppressants, with those who take it achieving less than a 5% weight loss compared with placebo.9 The FDA guidance for industry for weight loss drugs recommends that drugs brought through the approval process show for efficacy a difference in mean weight loss between product and placebo groups of at least 5% or that the proportion of subjects undergoing active treatment who lose ≥5% of baseline body weight be at least 35%.
