The drug relieved pain and improved several quality-of-life indicators.
Several studies have demonstrated that patients with fibromyalgia have abnormal central nervous system pain processing. Clinically, patients typically experience chronic hyperalgesia as well as pain from stimuli that are normally not noxious — just as do patients with diabetic neuropathy, postherpetic neuralgia, and migraine. Gabapentin is effective in treating those disorders.
A multi-institutional team performed a double-blind randomized controlled trial of gabapentin (1200–2400 mg/day) or placebo in 150 patients with fibromyalgia. During the 12-week study, more patients in the active treatment group reached the predefined endpoint of clinically significant pain relief (51% vs. 31%). The gabapentin-treated patients also had superior scores on several secondary instruments, including the vitality score of the SF-36 functional status instrument. Compared with the placebo group, the active treatment group more often had mild-to-moderate dizziness, sedation, and lightheadedness — likely adverse drug effects.
Comment: Gabapentin reduces the release of several neurotransmitters that are involved in pain processing, so the short-term efficacy demonstrated in this study is biologically plausible. A similar and newer drug, pregabalin, also has been shown in a randomized trial to be effective in treating fibromyalgia. It remains unclear whether gabapentin will remain effective, and free of serious adverse effects, when used longer than 12 weeks in fibromyalgia.
— Anthony L. Komaroff, MD
Published in Journal Watch General Medicine April 17, 2007