A recent study entitled “Melatonin analgesia is associated with improvement of the descending endogenous pain-modulating system in fibromyalgia: a phase II, randomized, double-dummy, controlled trial“, published in the BMC Pharmacology and Toxicology journal, observed that melatonin alone or in combination with amitriptyline significantly reduced pain in fibromyalgia patients.
Fibromyalgia is a disease characterized by widespread pain lasting for months to years (usually throughout the life of an affected patient) and a painful response to pressure in various specific body areas. Furthermore patients often also have stiffness of the body, fatigue, sleep disturbances, anxiety and depression. It estimated to affect as much as 2 to 8% of the population with 7 to 9 times more women affected compared to men.
Sleep disorders and alteration of the circadian rhythm (the physiological oscillation of body metabolism through the 24 hours) are very common in fibromyalgia patients. Melatonin is one of the main hormones in the body responsible for circadian rhythm synchronization. There is some evidence that melatonin treatment improves different types of chronic long-lasting pain, namely inflammatory and neuropathic pain.
Related: Read more about the latest chronic pain and pain management news.
As the available evidence on melatonin treatment efficacy for fibromyalgia is sparse, researchers from Hospital de Clínicas de Porto Alegre, Brazil, conducted a randomized clinical study with 63 patients. In their study, patients with confirmed fibromyalgia were randomized to three groups: amitriptyline 25mg (standard treatment), melatonin 10 mg at bedtime, and melatonin 10 mg + amitriptyline 25 mg.
Using the visual analogue scale investigators asked patients to measure pain in a scale of 0 to 10 after six weeks. Results showed that both melatonin alone and melatonin plus amitriptyline were better than amitriptyline alone for fibromyalgia pain treatment. Moreover, the group receiving a combination of the two treatments had better treatment efficacy and the highest decrease in pain symptoms.
Fibromyalgia patients suffer from a lack of inhibition of musculoskeletal pain, lower pain threshold and an altered pain modulation system function. In the patients under study these modulation systems were analyzed using the brain-derived neurotrophic factor and other additional exams. Importantly, melatonin was shown to further increase the function of these pain modulating systems when compared to amitriptyline.
There is a need for better fibromyalgia treatments as most therapies lack efficacy and/or have several adverse effects. In the future, melatonin might be a more efficient alternative to currently used treatments.