Uncertainties about the cardiovascular safety of sibutramine led to the SCOUT trial that is investigating sibutramine plus weight management in high-risk, overweight/obese patients. A 6-week lead-in period during which all patients received sibutramine permitted an initial assessment of tolerability. A total of 10,742 patients received sibutramine and 3.1% of these discontinued due to an adverse event; issues affecting more than 10 patients were drug intolerance, headache, insomnia, nausea, dry mouth, and constipation-, tachycardia-, and hypertension-related events. Serious adverse events, most commonly associated with the System Organ Class, Cardiac disorders, were reported by 2.7% of patients; however, the majority was not considered sibutramine-related. Adverse events relating to high blood pressure and/or pulse rate, whether reported as adverse events leading to discontinuation, or serious adverse events were reported by less than 0.2% of patients. No serious or individual events leading to discontinuation occurred in more than 25 patients. There were 15 (0.1%) deaths; 10 were attributed to a cardiovascular cause. Discontinuations for adverse events were lower than anticipated. Serious adverse events generally reflected sibutramine's known pharmacology or were related to cardiac disorders already present in this high-risk population. When compared with epidemiological data, overall mortality rate was low and sibutramine was well tolerated in this mainly off-label population. No new safety issues were detected.