Effect of milnacipran on body weight in patients with fibromyalgia

The purpose of this study was to evaluate the effects of milnacipran on body weight in patients with fibromyalgia.

ANALYSES WERE CONDUCTED IN THE FOLLOWING GROUPS: patients from three double-blind, placebo-controlled milnacipran trials (3 months, n = 2096; 6 months, n = 1008); 354 patients receiving milnacipran in placebo-controlled trials and double-blind extension studies (total ≥ 12 months of treatment); and 1227 patients in a long-term (up to 3.25 years) open-label milnacipran study.

In placebo-controlled trials, 77% of patients were overweight or obese at baseline (body mass index ≥ 25 kg/m(2)). Mean weight loss was found with milnacipran at 3 months (100 mg/day, -1.14 kg; 200 mg/day, -0.97 kg; placebo, -0.06 kg; P < 0.001) and 6 months (100 mg/day, -1.01 kg; 200 mg/day, -0.71 kg; placebo, -0.04 kg; P < 0.05). Approximately twice as many milnacipran-treated patients had ≥5% weight loss from baseline compared with placebo (3 and 6 months, P < 0.01). In extension studies, mean weight loss in patients receiving ≥12 months of milnacipran was -1.06 kg. In patients receiving ≥3 years of treatment in the open-label study, mean changes at 12, 24, 30, and 36-38 months were -1.16, -0.76, -0.19, and +0.11 kg, respectively. Among milnacipran-treated patients, rates of nausea (the most common adverse event) were lower among patients who lost weight than among those who did not (3 months, P = 0.02).

The majority of patients with fibromyalgia in the milnacipran studies were overweight or obese. Milnacipran was associated with mean weight loss at 3 and 6 months (P < 0.05 versus placebo) and at 12 and 24 months of treatment, with mean changes drifting back to baseline at 30 months (-0.19 kg) and 36-38 months (+0.11 kg, no placebo comparison).