Milnacipran Improves Fatigue and Pain in Fibromyalgia Patients

AUSTIN, TX— Milnacipran treatment improves fatigue in fibromyalgia patients and improves pain regardless of baseline levels of fatigue, as reported by Philip Mease, MD, from the Seattle Rheumatology Associates and Swedish Medical Center, Seattle, WA, and colleagues at the American Pain Society's 30th Annual Scientific Meeting.

The authors pooled data from three Phase 3, randomized, double-blind, placebo-controlled studies in fibromyalgia patients, who were randomized to placebo (n=1,133), milnacipran 100mg/day (n=1,139), or milnacipran 200mg/day (n=837). The post hoc analysis sought to evaluate the effect of fatigue on fibromyalgia patients, the extent that fatigue improvement is independent of pain reduction after milnacipran therapy, and to assess if baseline fatigue score impacts the overall outcome.

After a dose-escalation phase, patients underwent 12–24 weeks of stable-dose treatment. Fatigue was measured by collecting 24-hour pain visual analog scale (VAS) data on an electronic diary and by using the Multidimensional Fatigue Inventory (MFI; 20 [no fatigue to 100 [most fatigue]) total and subscale scores (general, mental, and physical fatigue; reduced activity; reduced motivation). Pearson correlation coefficients were determined for the relationships between improvements in MFI total score and improvements in pain VAS and endpoint Patient Global Impression of Change (PGIC) score. Changes in pain VAS scores were determined for patients then stratified into tertiles based on their baseline MFI total score (ie, MFI ≤63; MFI >63 and ≤74; MFI >74).

At the three-month endpoint, significant improvements over placebo with both doses of milnacipran were observed in MFI total score (P<0.01). Milnacipran 200mg/day treatment resulted in significant improvements in all MFI subscale scores vs. placebo (P<0.05); milnacipran 100mg/day significantly improved general fatigue, physical fatigue, and reduced motivation subscale scores vs. placebo (P<0.05). Milnacipran-treated patients stratified to all baseline fatigue intensity tertiles had significantly reduced pain VAS scores vs. placebo (P<.05). In milnacipran-treated patients, improvements in MFI total score correlated only moderately well with improvements in pain VAS (r=0.4729) and PGIC (r=0.5042).

Dr. Mease et al concluded that these results suggest that milnacipran treatment improves fatigue in fibromyalgia patients and improves pain regardless of baseline levels of fatigue. Furthermore, improvements in fatigue and improvements in pain did not appear to be strongly correlated and should be monitored independently