Fibromyalgia syndrome (FMS) is a musculoskeletal disorder that causes muscle aches, fatigue and tenderness at specific locations in the body. A recent study tested the beneficial role of melatonin, a natural hormone produced in the body, in the treatment of muscle pain in patients suffering from fibromyalgia. In this study, melatonin was tested alone, and in combination with the anti-depressant drug, fluoxetine, to evaluate its usefulness in the treatment of FMS. The study concluded that a combination of melatonin and fluoxetine was effective in the treatment of patients with FMS.

Fibromyalgia syndrome (FMS) leads to severe and long-term muscle pain, fatigue and stiffness, increased sensitivity to pain, loss of sleep, anxiety, memory loss and depression. The exact pathology and treatment of this condition is unknown. Various studies have shown that the production of melatonin in patients with FMS is relatively lower during the dark hours of the day when compared to normal individuals. Melatonin is released by the pineal gland in the brain at night. It maintains the diurnal rhythm in humans. A few studies have shown the benefits of melatonin, in terms of reduction in pain, sleep disturbances and tenderness, when administered to patients suffering from FMS. Unlike previous studies, the present study evaluates the effectiveness of melatonin in combination with fluoxetine, an antidepressant drug, in the treatment of patients with FMS.


  • This study was performed on six males and 95 females who were suffering from FMS.
  • All the participants were divided randomly into four groups. Group A consisted of 24 patients who were administered with 20 mg of fluoxetine every day, while group B had 27 patients who received a daily dose of 5 mg of melatonin. Twenty seven patients in group C were administered a combination of 20 mg of fluoxetine and 3 mg of melatonin, while 23 patients in group D were administered a combination of 20 mg of fluoxetine and 5 mg of melatonin.
  • Fluoxetine was given in the morning and melatonin was given at night, once a day, for eight consecutive weeks.
  • All the patients were evaluated for symptoms of the disease before and after the completion of the study, using a standardized FMS questionnaire.

Key findings

  • The results of this study showed that at the end of the study, the patients belonging to group A had 21.5% reduction in symptoms of FMS. Similarly, patients belonging to group B showed 18.9% reduction in symptoms of FMS.
  • The decrease in the disease symptoms was more pronounced in patients who were administered a combination of both melatonin and fluoxetine. The patients belonging to group C showed 28.8% reduction and those of group D showed 28.9% reduction in symptoms of FMS.
  • It was also observed that physical impairment was visibly reduced by 23.7% in patients belonging to group C and by 37% in those of group D.

Next steps/Shortcomings
Due to the complexity of the disease, it is difficult to evaluate the effect of drugs and the outcome of treatment on patients with FMS. The beneficial effects of melatonin may be due to a “complex interplay between pain, sleep disturbances, and depression”, which are common symptoms of FMS. This study, however, failed to investigate the actual mechanism behind the beneficial role of the combination of melatonin and fluoxetine in the treatment of the disease. Also, their combined action on the central nervous system is not clearly explained.

This is the first study to have evaluated the effect of a combination of melatonin and fluoxetine in the treatment of fibromyalgia. According to this study, these two drugs reduce the symptoms of FMS by enhancing each other’s activity, since both these agents are individually capable of relieving the symptoms of the disease. Melatonin is found to play a regulatory role in sleep modulation and sensitivity to pain. Its antioxidant properties help in relieving the damage caused due to production of oxidants in patients with FMS. These properties of melatonin, in combination with the antidepressant effects of fluoxetine, are extremely effective in the treatment of FMS.

For More Information:
Adjuvant Use of Melatonin for Treatment of Fibromyalgia
Publication Journal: Journal of Pineal Research, December 2010 By Saad Abdul-Rehman Hussain; Ihab Ibrahim Al-Khalifa From the University of Baghdad, Baghdad, Iraq

*FYI Living Lab Reports Are Summaries of the Original Research.