A systematic review and mixed treatment comparison of the efficacy of pharmacological treatments for fibromyalgia

Objectives: To review the literature on pharmacological treatments for fibromyalgia.

Methods: Relative efficacy was estimated in terms of outcome measures highlighted by the Outcome Measures in Rheumatology Network using a Bayesian mixed treatment comparison (MTC) meta-analysis. Randomized controlled trials reporting treatments for fibromyalgia were identified by systematically reviewing electronic databases (Cochrane Library, Medline, EMBASE; accessed February 2008) and conducting manual bibliographic searches.

Results: Forty-five randomized controlled trials met the prespecified inclusion criteria for the systematic review. There were limited robust clinical data for some therapeutic classes (tricyclic antidepressants, analgesics, sedative hypnotics, monoamine oxidase inhibitors) and only 21 studies met the more stringent criteria for inclusion in the MTC. The majority of studies included in the MTC assessed the anticonvulsant pregabalin (n = 5) or the serotonin norepinephrine reuptake inhibitors (SNRIs) duloxetine (n = 3) and milnacipran (n = 3). Licensed doses of pregabalin and duloxetine were significantly (P < 0.05) more efficacious than placebo in terms of absolute reduction in pain, number of "responders" (≥30% reduction in pain), or change in Fibromyalgia Impact Questionnaire score (pregabalin 450 mg/d only). There was no significant difference between licensed doses of pregabalin and duloxetine for these outcomes. However licensed doses of pregabalin produced significantly greater improvements in sleep compared with milnacipran (as measured by Medical Outcomes Study Sleep Scale).

Conclusions: The current study confirms the therapeutic efficacy of pregabalin and the SNRIs, duloxetine and milnacipran, in the treatment of fibromyalgia. Given their different modes of action, combination therapy with pregabalin plus an SNRI should be investigated in future research.