Most patients with fibromyalgia in milnacipran trials were overweight or obese and initially lost weight during treatment before returning to baseline weight, according to study results.
Researchers studied patients (mean age, 49.6 years; 95.8% female; 92.7% white) with fibromyalgia in three double-masked, placebo-controlled trials for milnacipran (3 months, n=2,096; 6 months, n=1,008), as well as 354 patients receiving milnacipran in placebo-controlled trials and double-masked extension studies, with a total of at least 12 months of treatment; and 1,227 patients in an open-label, long-term (up to 3.25 years) milnacipran study.
Baseline weight information was available for 3,104 patients, with mean body weight of 82.4 kg and mean BMI, 30.7 kg/m2; 77% were classified as overweight or obese and 49% , obese. Patients on milnacipran treatment lost weight at 3 months (100 mg/day, -1.14 kg; 200 mg/day, -0.97 kg; placebo, -0.06 kg; P<.001) and 6 months (100 mg/day, -1.01 kg; 200 mg/day, -0.71 kg; placebo, -0.04 kg; P<.05). At least 5% weight loss from baseline was experienced by twice as many patients treated with milnacipran compared with placebo (3 and 6 months, P<.01). Mean weight loss in patients receiving at least 12 months of milnacipran in the extended studies was -1.06 kg. Mean weight changes at 12, 24, 30 and 36-38 months were -1.16, -0.76, -0.19 and +0.11 kg, respectively for patients receiving at least 3 years of treatment in the open-label study. Nausea was the most common adverse effect for patients receiving milnacipran treatment, with rates lower among patients who lost weight than those who did not (3 months, P=.02).
“In light of these potential weight problems, the effects of medication on body weight may need to be considered when managing these patients,” the researchers concluded. “Overall, mean weight changes observed in … studies suggested that treatment with milnacipran for [at least] 12 months was not associated with weight gain. In addition, no mean weight gain was found in patients receiving up to 30 months of milnacipran treatment in a long-term, open-label study, with mean weight to above baseline values in patients receiving [at least] 3 years of treatment. Patients with weight problems may benefit from a multidisciplinary treatment approach.”
Disclosure: See the study for a full list of relevant disclosures.