Is DL-fenfluramine a Potentially Helpful Drug Therapy in Overweight Adolescent Subjects?

We have studied the therapeutic effects of two different doses (30 mg and 60 mg, twice daily) of DL-fenfluramine (DL-F) in, respectively, prepuberal (11-13 years old) and adolescent subjects (14-17 years old). Sixty-eight obese subjects were recruited for this study (22 boys, 36 girls, aged 10-17 years old) with body mass index ranging from 24.5 to 44.0 kg/m2, absolute weight ranging from 37.0 to 119.5 kg and % over IBW ranging from 122% to 260%. Results were compared to a placebo treated group of obese adolescent patients (n = 17), 6 boys and 11 girls, aged 10-17 years old, BMI ranging from 26-44 kg/m2, absolute weight 53.1 to 96.5 kg, and with 129% to 253% over IBW. In the DL-F-treated subjects most patients (n = 41) had a continuous weight loss during 12 months but 27 individuals were unable to lose any additional weight after the initial 6 months of the trial. Taken together 65% of all patients lost weight during DL-F treatment (12 months) whereas only 17.4% of the placebo group lost a significant (> 10% BMI) amount of excess weight. Also the placebo group had a higher withdrawal rate (57%) as compared with the DL-F-treated group (24%). There was a significant (p < 0.05) decrease of the mean +/- SD of the BMI (at 6 and 12 months of therapy). No significant change of the BMI was observed for control group. Minor adverse side effects consisted of a brief period of drowsiness and dry mouth. Our findings indicated that the continuous administration of DL-Fenfluramine might help obese adolescent subjects adhere to a diet and to maintain the weight loss achieved without major or harmful adverse effects.