Fibromyalgia (FMS) is a chronic musculoskeletal disorder characterized by generalized muscular pain and tenderness at specific anatomical sites. Although melatonin was effective in treating the pain associated with this syndrome, no defined clinical evidence supports this claim. The present study was designed to evaluate the clinical significance of using melatonin, alone or in combination with fluoxetine in FMS. A double-blind clinical study was conducted on 45 patients with FMS randomized into 4 groups; group A, treated with fluoxetine 20mg/day alone; group B, treated with melatonin 5mg alone; group C, treated with combination of fluoxetine 20 mg+3 mg melatonin; group D treated with combination of fluoxetine 20 mg+5 mg melatonin. Both fluoxetine and melatonin were given once daily in the morning and night time respectively for 8 weeks. Each patient clinically evaluated using Fibromyalgia Impact Questionnaire (FIQ). Serum levels of serotonin, malondialehyde and nitric oxide were also evaluated. Using melatonin (3 and 5mg/day) in combination with 20mg/day fluoxetine significantly decreased total FIQ score values; the combination therapy significantly decreased serum serotonin level associated with reduction in the oxidative stress parameters (MDA and NO). In conclusion, adjuvant use of melatonin with fluoxetine improves the biochemical and clinical parameters of FMS patients.
Key words: Fibromyalgia; Oxidative Stress; Serotonin; MDA; Nitric oxide