Effect of low-dose metoprolol in combination with sibutramine therapy in normotensive obese patients: a randomized controlled study

Objective: Sibutramine is an effective appetite suppresser agent, but treatment is often complicated with side effects, including palpitations and hypertension. In this study, we aimed to assess the effect of low-dose cardio-selective beta blocker combination with sibutramine treatment. Methods: In total, 57 obese subjects were enrolled in the study and separated into two groups in order to receive sibutramine 10 mg/day plus placebo (group P) or sibutramine 10 mg/day plus metoprolol 25 mg/day (group M). Patients were evaluated in the beginning and at the end of the third month with anthropometric measurements, biochemical analysis, peripheral insulin resistance, and ambulatory 24 h blood pressure monitoring. Side effects were evaluated with a visual analog scale. Results: During the study period, the drop-out rate was significantly higher in group P compared with group M (55 and 21%, respectively, P=0.014). Palpitations and headache were prominent symptoms in group P. Diastolic blood pressure (78.6+/-11.6 and 70.6+/-4.8 mmHg, respectively, P=0.013) and mean heart rate (84.3+/-6.1 and 75.8+/-8.4 beats/min, respectively, P=0.003) were significantly higher in group P compared with group M at the end of the third month. Weight loss was similar between the two groups (100.9+/-11.5 to 91.8+/-12.8 kg for group P, P<0.0001 and 97.9±13.2 to 88.9±13.8 kg for group M, P<0.0001). We did not find any deleterious effect of metoprolol on metabolic parameters. Conclusion: Addition of low-dose metoprolol to sibutramine therapy increased patient compliance to the treatment, and decreased the frequency and severity of side effects including hypertension and palpitations, without decreasing the drug efficacy or causing significant deleterious changes in metabolic parameters.