[Obesity: principles of drug therapy]

Obesity is a major global public health problem. In many instances, a combination of diet modification, increased physical activity and behavior therapy fail or are insufficient for sustained weight loss. In these situations, drug therapy may be helpful. However, drug treatment of obesity resulted in unexpected devastating events in recent years. In the late sixties, aminorex caused an epidemic of pulmonary hypertension with high mortality rates. Dexfenfluramine and phentermine were also associated with the development of pulmonary hypertension and with alarming reports of cardiac valvular abnormalities. Therefore, these drugs were withdrawn from the market. Newer drugs, like sibutramine, a serotonin and norepinephrine reuptake inhibitor, and orlistat, a specific lipase inhibitor, reduce body weight significantly compared to placebo. In combination with a hypocaloric diet, weight loss of three to ten kilos can be achieved. Pharmacotherapy is limited to patients with a body mass index greater than 30 kg/m2, if non-pharmacological treatment programs have failed. The drugs should be prescribed under strict medical surveillance only.