We tested whether 14 wk of
dexfenfluramine (30 mg) or
fluoxetine (40 mg) treatment would prevent
weight gain after subjects quit smoking. Normal-weight women (n = 144) were randomly assigned to
drug or placebo on a double-blind basis for 2 wk before quitting smoking and 12 wk thereafter. The
fluoxetine group had more dropouts (28/49, 57.1%) than the
dexfenfluramine group (17/47, 36.2%), with an intermediate number of dropouts from the placebo group (21/48, 43.8%). All groups gained weight during treatment, but their amount and pattern of
weight gain differed. In the first month after quitting smoking, the placebo group gained more weight than either the
dexfenfluramine or
fluoxetine group (P < 0.05). By 2 mo postcessation,
dexfenfluramine still suppressed
weight gain in comparison with placebo (P < 0.05);
weight gain with
fluoxetine was not differentiable from either
dexfenfluramine or placebo. By 3 mo postcessation, the
dexfenfluramine group had gained 1.0 +/- 0.7 kg, significantly less than either the placebo (3.5 +/- 0.7 kg) or
fluoxetine (2.7 +/- 0.5 kg) groups. Three months after
drug discontinuation, formerly medicated, but not placebo patients, showed additional
weight gain, eliminating differences between groups. Results indicate that
weight gain, an adverse accompaniment of smoking cessation, can be minimized to some degree by serotoninergic drugs, although only for the duration of
drug treatment.