Tratamiento farmacológico de la obesidad

Abstract

The treatment of obesity creates many difficulties in the daily clinic, giving rise to a high rate of failure, since in most of the patients relapses are frequent, recovering most of the lost weight. Prevalence of obesity in the Spanish population aged 25-60 years (SEEDO 2000) is 14.5% and 39% of this group is overweight. It is difficult to evaluate the economic costs generated by obesity, this being mainly derived from treatments of related diseases and their social adaptation. In Spain, Delphi study calculated that the economic cost of obesity is 6.9% of the annual sanitary cost. Pharmacological therapy of obesity has often been seen as a controversial option, and it is currently undergoing re-evaluation, as a result of the appearance of two new drugs, sibutramine and orlistat, and the sprouting of the concept of long term anti-obesity pharmacological therapy along with weight-reducing diets and physical activity. Sibutramine is a tertiary amine of synthesis whose mechanism of action associates, inhibition of the reuptake of noradrenaline and serotonin in the cerebral areas controlling the appetite and increasing of the basal metabolic rate, which is characteristically diminished during the loss of weight. Unlike fenfluramine and dexfenfluramine, it does not induce serotonin liberation and no association to heart valve problems has been described. Sibutramine produces a significant dose-related weight loss, with good tolerance on a daily dose of 10 to 15 mg. Orlistat is an inhibitor of gastrointestinal lipases and therefore, prevents the hydrolysis of triglycerides into monoglycerides on the intestinal lumen. It produces a dose-related reduction of dietary fat absorption, near to the maximum when 120 mg are administered before or up to one hour after meals. Orlistat reduces 30% of fat absorption, hence contributing to a negative energy balance. Orlistat has recently been approved by FDA for the treatment of children obesity. The knowledge of the mechanism of action of hormones such us leptin and ghrelin, involved in the circuit of hunger satiety, as well as some other new synthetic molecules helding thermogenic and lipolytic activity constitutes a new and promising field of investigation. All these substances contribute to increase the number of therapeutic tools to fight the true epidemic of the developed world, obesity.