Dexfenfluramine. Its place in weight control

Dexfenfluramine, the dextrostereoisomer of fenfluramine, is a pure serotonin (5-hydroxytryptamine) agonist, apparently devoid of any additional antidopaminergic or sympathomimetic effects. The drug is approximately twice as effective as its racemic predecessor in reducing food intake in animals, and at a dose of 30 mg/day dexfenfluramine substantially modifies eating behaviour in man. Thus, a reduction in the motivation to eat and fewer snacking episodes were seen in volunteers treated with the drug, while total caloric and carbohydrate (but not protein) intakes were reduced in obese carbohydrate cravers. In clinical studies in obesity, dexfenfluramine combined with dietary support has produced mean weight reductions superior to those achieved with placebo over 3-month treatment periods. Importantly, the drug appears to maintain its weight-reducing effects for at least 12 months, without serious adverse effects. Dexfenfluramine appears to possess many of the properties of an 'ideal' pharmacotherapeutic agent for obesity. However, further long term clinical studies are required to confirm the promising efficacy and safety data obtained to date, and to further define the most appropriate indications for its use. Ideally, the drug should be used as adjunctive treatment in the clinical management of more severe cases of obesity, which are refractory to simpler supportive measures such as dietary or psychological counseling.