International trial of long-term dexfenfluramine in obesity.

In a randomised, placebo-controlled, double-blind study, 822 obese patients of both sexes were given either dexfenfluramine (dF), 15 mg twice daily (404), or placebo (418) in addition to a calorie-restricted diet for 1 year. Patients in both groups lost weight significantly in the first 6 months; after 6 months dF patients had a higher cumulative mean weight loss. Dropout rates were lower in dF patients than in placebo patients, mainly because of dissatisfaction with weight loss in the latter group. More than twice as many dF patients as placebo patients achieved a given weight loss; but more dF patients than placebo patients had transient side-effects (tiredness, diarrhoea, dry mouth, polyuria, and drowsiness).