Fenfluramine in the treatment of non-insulin-dependent diabetics: hypoglycemic versus anorectic effect.

A few studies have suggested that the anorectic drug fenfluramine has a hypoglycemic effect. The major problem in interpreting those studies, however, is the difficulty in dissociating the effect of weight loss on blood glucose from the direct effect of fenfluramine. In a double-blind study of 28 diabetic females treated with oral hypoglycemic agents, a significant decrease in fasting blood glucose (from 195 +/- 17 mg/dl to 152 +/- 15 mg/dl after four weeks, and to 155 +/- 14 mg/dl after eight weeks) was observed in fenfluramine-treated patients (n = 14). Corresponding values in the placebo group were 185 +/- 12 mg/dl and 201 +/- 16 mg/dl respectively. Glucose tolerance after a standard meal was also improved after fenfluramine treatment. Weight loss was minimal and not significantly different for the two groups. From these observations, it can be concluded that fenfluramine has a lowering effect on blood glucose which is independent of its effect on weight.