Forty RCTs evaluated the effect of pharmacotherapy on weight loss. In most studies, advice or behavioral therapy that promoted reduced energy intake and increased physical activity was included in all treatment arms, including the placebo group. The RCTs addressed the following pharmacotherapies: BRL 26830A (696), cimetidine (699), dexfenfluramine (386, 387, 390-393, 414, 478, 506-508, 711, 745, 746), ephedrine (695, 697, 747), fenfluramine (478), fenfluramine and phentermine (395, 514, 748, 749), femoxetine (750), fluoxetine (408, 712, 730, 734, 751, 752), mianserine (753), orlistat (407, 710), phenylpropanolamine (511, 512), phentermine (176, 754), testosterone (698), yohimbine (755), and sibutramine (510). Most of the patients in these trials weighed more than 120 percent of their ideal body weight or had a BMI of 25 to 30.
RCTs that examined cimetidine, mianserine, yohimbine, testosterone, femoxetine, and BRL 26830A were not considered either because they are not now being studied for obesity treatment or because they are not approved by the Food and Drug Administration (FDA) for obesity treatment. Fluoxetine, and other selective serotonin reuptake inhibitors commonly used for the treatment of depression, have not been approved for use as antiobesity agents. Ephedrine has been tested alone and in combination with caffeine. Although a significant 3.4 kg difference was found at 6 months in patients treated with this combination compared with those on placebo (695), the ephedrine/caffeine combination is not approved by the FDA for use in the United States. In addition, studies with a dropout rate greater than 35 percent were not considered (711). As of September 1997, two FDA-approved drugs, dexfenfluramine and fenfluramine, were withdrawn from the market by the manufacturer due to an observed association with valvular heart disease in patients taking the combination of phentermine/fenfluramine, or "Redux." The panel's deliberations on the evidence regarding these drugs are included in the report for informational purposes only.