DEXFENFLURAMINE HYDROCHLORIDE - AN ANOREXIGENIC AGENT

The pharmacology, pharmacokinetics, efficacy, and adverse effects of d exfenfluramine hydrochloride are reviewed. Dexfenfluramine, the dextro rotatory isomer of fenfluramine, is indicated for use in the managemen t of obesity in patients with a body mass index of greater than or equ al to 30 kg/m(2), or greater than or equal to 27 kg/m(2) in the presen ce of other risk factors. Unlike fenfluramine, dexfenfluramine is a pu re serotonin agonist. Dexfenfluramine may mimic the effect of carbohyd rate intake. Systemic bioavailability is about 68%, and the drug is me tabolized in the liver. In randomized, placebo-controlled trials, dexf enfluramine was effective in reducing weight in obese patients given t he drug for three or six months. In trials lasting one year, the stati stically significant weight loss occurred during months 4 to 6. Dexfen fluramine reduces blood pressure, percent glycosylated hemoglobin, and concentrations of blood glucose and blood lipids, but these benefits may be indirect. Dexfenfluramine may also be of some value in controll ing eating habits in diabetic patients, preventing weight gain after s moking cessation, and treating bulimia, seasonal affective disorder, n euroleptic-induced obesity, and premenstrual syndrome. Dexfenfluramine 's most frequent adverse effects are insomnia, diarrhea, and headache; it has also been associated with primary pulmonary hypertension. The drug should not be combined with other serotonergic agonists because o f the risk of serotonin syndrome. The recommended dosage is 15 mg twic e daily. Dexfenfluramine is effective in the treatment of obesity in s elected patients. Because its efficacy is lost after six months of con tinuous treatment, it should be viewed primarily as an adjunct to diet and exercise.