We assessed the efficacy and safety of extended-release gabapentin in a 15-week, open-label, single-arm, single-center study in patients with fibromyalgia (FM).
Subjects with documented diagnosis of FM were allowed to participate in the study. We opened enrollment to those who have tried and failed gabapentinoids such as gabapentin or pregabalin due to side effects. Subjects with autoimmune conditions, and or taking opioids for management of their FM pain, were excluded from the study. Subjects were given an extended-release gabapentin starter pack and treated for total of 12 weeks. The primary study endpoint of pain relief was measured using Numeric Pain Rating System (NPRS) scores, and secondary study endpoints were measured with Fibromyalgia Impact Questionnaire (FIQ), Patient's Global Impression of Change (PGIC), and Medical Outcome Sleep questionnaires (MOS).
A total of 34 subjects were enrolled and 29 subjects completed the starter pack (85%). Patients reported significant pain relief on NPRS by end of 4 weeks (P < 0.0001) on NPRS. Subjects also reported similar magnitude of improvements in FM and its impact on daily life by end of 4 weeks on FIQ (P < 0.0001). Survey of MOS showed our subjects reporting improved sleep quantity (on average, 1.2 hours over baseline) with gradual and statistically significant improvement in quality. Improvements in primary and secondary measurements were reflected in PGIC, with significant improvement in patient's impression of FM by week 8.
Small sample size, geographical bias, relatively short duration of treatment, and single-arm study without control group.
Extended-release gabapentin relieved FM pain symptoms and improved quality-of-life for the FM subjects studied. Subjects reported improvements in both quantity and quality of sleep.