Sibutramine in weight control: A dose-ranging, efficacy study

We tested the safety and efficacy of sibutramine, 5 and 20 mg, and placebo on weight loss. Medication was added to caloric restriction, behavior modification, and exercise in a parallel-group, double-blind clinical trial. Participants were 130% to 180% of ideal body weight and in good health. The study lasted 12 weeks over Thanksgiving, Christmas, and New Year's Day. Weight loss during 8 weeks of study medication was: placebo, 1.4 ± 2.1 kg (n = 19); 5 mg sibutramine, 2.9 ± 2.3 kg (n = 18); and 20 mg sibutramine, 5.0 ± 2.7 kg (n = 18) (p < 0.05 sibutramine, 5 and 20 mg, versus placebo; p < 0.05 sibutramine, 20 mg versus 5 mg). There is a significant dose-effect relationship. Five participants left the study before completion, all because of adverse events: placebo (one patient), 5 mg sibutramine (one patient), and 20 mg sibutramine (three patients). Sleep difficulties were noted by eight participants (20 mg sibutramine, seven patients; 5 mg, one patient; and placebo, no patients). Six of 21 participants receiving 20 mg complained of irritability, unusual impatience, or “excitation.” Sibutramine, 5 and 20 mg, added to a multimodal program assisted participants in losing weight. Clinical Pharmacology and Therapeutics (1991) 50, 330–337; doi:10.1038/clpt.1991.144