This study (A0081057) was designed to evaluate the long-term safety and efficacy of pregabalin treatment of fibromyalgia (FM).

In this 1-year, open-label (OL) extension of a 13-week randomized, placebo-controlled trial of pregabalin FM patients had the option of continuing pregabalin at doses of 150 to 600 mg/d. Efficacy was measured by the Short-Form McGill Pain Questionnaire (SF-MPQ), which included sensory and affective pain descriptors, Present Pain Intensity (PPI) index, and a Visual Analog Scale (VAS).

429 of 431 screened patients entered OL treatment, 249 (58%) completed, 70 (16.3%) discontinued due to an adverse event (AE), and 110 (25.7%) discontinued for other reasons. Median duration of treatment with pregabalin was 357 days (range, 1-402 days); 114 received pregabalin for ≥1 year. No clinically meaningful increases in dose were noted over the OL treatment period. Weighted mean dose was 414 mg/d in the first 3 months of treatment and 444 mg/d after 9 months of treatment. SF-MPQ sensory, affective, and total scores were improved relative to baseline, VAS pain score decreased 21 points (0-100 scale), and PPI decreased 0.9 point (0-5 scale). The most frequently reported all-causality AEs were dizziness, somnolence, peripheral edema, and increased weight, most of which were mild to moderate in intensity and of limited duration.

Pregabalin administered for up to 1 year was generally well tolerated by FM patients without evidence of dose increase over time. The sustained improvement in pain measures during OL treatment was consistent with that in shorter term double-blind trials.