A double-blind placebo-controlled trial of milnacipran in the treatment of fibromyalgia

Fibromyalgia syndrome is a systemic disorder of widespread pain which is thought to result from abnormal pain processing within the central nervous system. There are no currently approved treatments for this indication. Antidepressants appear, however, to be effective, especially those with an action on noradrenergic neurotransmission. The objective of the present study was to test the efficacy of the dual action noradrenaline and serotonin reuptake inhibitor antidepressant, milnacipran, in the treatment of fibromyalgia. The 125 patients, who were enrolled in a double-blind, placebo-controlled, flexible dose escalation trial, were randomized to receive placebo or milnacipran for 4 weeks of dose escalation (up to 200 mg/day), followed by 8 weeks at a constant dose. The study evaluated the efficacy and safety of milnacipran for the treatment of pain and associated symptoms such as fatigue, depressed mood and sleep. 75% of milnacipran-treated patients reported overall improvement, compared with 38% in the placebo group (p < 0.01). Furthermore, 37% of twice daily milnacipran-treated patients reported at least 50% reduction in pain intensity, compared with 14% of placebo-treated patients (p < 0.05). 84% of all milnacipran patients escalated to the highest dose (200 mg/day) with no tolerability issues. Most adverse events were mild to moderate in intensity, and transient in duration. These results suggest that milnacipran may have the potential to relieve not only pain but several of the other symptoms associated with fibromyalgia.