Context: No long-term studies have compared centrally acting drugs for treating obesity.
Objective: To compare the efficacy and safety of diethylpropion (DEP), fenproporex (FEN), mazindol (MZD), fluoxetine (FXT) and sibutramine (SIB) in promoting weight loss.
Design and setting: A prospective, randomized, placebo (PCB)-controlled study conducted at a single academic institution.
Patients: A total of 174 obese premenopausal women.
Intervention: Participants randomly received DEP 75 mg (n=28), FEN 25 mg (n=29), MZD 2 mg (n=29), SIB 15 mg (n=30), FXT 20 mg (n=29) or PCB (n=29) daily over 52 weeks. Diet and physical activity were encouraged.
Main outcome measures: The primary endpoints were changes in body weight and the proportion of women who achieved at least 5% weight loss by week 52 in the intent-to-treat population. Other measurements included anthropometry, safety, metabolic and cardiovascular parameters.
Results: Weight loss was greater than PCB (-3.1±4.3 kg) with DEP (-10.0±6.4 kg; P<0.001), SIB (-9.5±5.9 kg; P<0.001), FEN (-7.8±6.9 kg; P<0.01) and MZD (-7.4±4.9 kg; P<0.01) but not with FXT (-2.5±4.1 kg). Ten (33.3%) women lost⩾5% of their initial weight with PCB, compared with 20 (71.4%; P<0.001) with DEP, 20 (69%; P<0.02) with FEN, 21 (72.4%; P<0.01) with MZD, 22 (73.3%; P<0.001) with SIB and 10 (35.5%) with FXT. Each medically treated group experienced more adverse events compared with PCB (P<0.001). Compared with PCB, constipation was more prevalent with DEP, SIB and MZD (P<0.01); anxiety was more prevalent with DEP (P=0.01); and irritability occurred more frequently with DEP and FEN (P=0.02). Significant improvements in the depression and anxiety scores, binge-eating episodes and quality of life correlated with weight loss.
Conclusion: The centrally acting drugs DEP, FEN, MZD and SIB were more effective than PCB in promoting weight loss in obese premenopausal women, with a satisfactory benefit-risk profile.