Fibromyalgia, a chronic musculoskeletal pain disorder of unknown etiology, is characterized by widespread musculoskeletal pain, fatigue, and multiple tender points; the disease affects 3 to 6 million Americans. A person is considered to have fibromyalgia if he or she has widespread pain in combination with tenderness in at least 11 of 18 specific tender point sites.~Treatment of fibromyalgia requires a comprehensive approach and includes aerobic exercise, heat and massage, antidepressant medications, and relaxation. Gabapentin, a medication used to treat seizures, has been shown to work on pain transmission pathways and may relieve the pain associated with fibromyalgia. This study will assess the efficacy of gabapentin in reducing pain severity in fibromyalgia as measured by the average pain item of the Brief Pain Inventory (BPI) score.~Patients will be randomized to receive gabapentin or placebo. The gabapentin dose will be titrated for persisting symptoms and as tolerated during the first 6 weeks of the study, reaching final doses between 1800 mg/day and 2400 mg/day. Patients will then continue on the final dose for the remaining 6 weeks of the study. Following completion of the 12 week treatment phase, patients will be tapered off of the medication over 1 week.~The effectiveness of gabapentin will be assessed using the BPI. The BPI is a self-administered questionnaire that measures the severity of pain and the interference of pain on function over the past 24 hours. Other assessments will include the total Fibromyalgia Impact Questionnaire (FIQ) score; six 11-point Likert-type scales in the FIQ that measure pain, fatigue, morning tiredness, stiffness, anxiety, and depression; the mean tender point pain threshold; Clinical Global Impression of Severity (CGI-Severity); Patient Global Impression of Improvement (PGI-Improvement); the Short-form McGill Pain Questionnaire (SF-MPQ); the Medical Outcomes Study Short Form-36 (SF-36); the Montgomery Asberg Depression Rating Scale (MADRS); and the Medical Outcomes Sleep Scale (MOS-Sleep).
This study will assess the safety and effectiveness of the drug gabapentin in reducing pain associated with primary fibromyalgia.