In this randomized, double-blind clinical trial of 150 people (90 percent women) with fibromyalgia, Lesley M. Arnold, M.D., director of the Women's Health Research Program at the University of Cincinnati College of Medicine, and her colleagues found that those taking 1,200 to 2,400 mg of gabapentin daily for 12 weeks displayed significantly less pain than those taking a placebo. Patients taking gabapentin also reported significantly better sleep and less fatigue. For the majority of participants, the drug was well tolerated. The most common side effects included dizziness and sedation, which were mild to moderate in severity in most cases.
The NIH press release announcing the research results noted that, although the researchers cannot say with certainty how gabapentin helps reduce pain, Dr. Arnold says one possible explanation involves the binding of gabapentin to a specific subunit of voltage-gated calcium channels on neurons. "This binding reduces calcium flow into the nerve cell, which reduces the release of some signaling molecules involved in pain processing," she says.
NIAMS Director, Stephen I. Katz. M.D., Ph.D., added that, "While gabapentin does not have Food and Drug Administration approval for fibromyalgia, I believe this study offers additional insight to physicians considering the drug for their fibromyalgia patients. Fibromyalgia is a debilitating condition for which current treatments are only modestly effective, so a study such as this is potentially good news for people with this common, painful condition."