New developments in the pharmacological treatment of fibromyalgia

Fibromyalgia is a chronic, musculoskeletal pain condition that predominately affects women. Although fibromyalgia is common and associated with substantial morbidity and disability, there are no US Food and Drug Administration-approved treatments. However, progress has been made in identifying pharmacological and non-pharmacological treatments for fibromyalgia. Recent pharmacological treatment studies have focused on selective serotonin and norepinephrine reuptake inhibitors, which enhance serotonin and norepinephrine neurotransmission in the descending pain pathways and lack many of the adverse side effects associated with tricyclic medications. Promising results have also been reported for medications that bind to the α2δ subunit of voltage-gated calcium channels, resulting in decreased calcium influx at nerve terminals and subsequent reduction in the release of several neurotransmitters thought to play a role in pain processing. There is also evidence to support exercise, cognitive behavioral therapy, education, and social support in the management of fibromyalgia. It is likely that many patients would benefit from combinations of pharmacological and non-pharmacological treatments, but more study is needed. Introduction This review focuses on recent randomized, controlled studies of pharmacological and non-pharmacological therapies for fibromyalgia. Clinical recommendations for the management of fibromyalgia will be based on the available evidence from these trials. Although much work remains, progress has been made in identifying potentially efficacious treatments for fibromyalgia. The treatment of fibromyalgia is a rapidly growing area of research, and it is likely that treatment options will continue to expand for patients with fibromyalgia. Although fibromyalgia causes substantial morbidity and disability, there are no US Food and Drug Administration (FDA)-approved or European Medicines Agency (EMEA)approved treatments. Strategies that are being pursued to develop better treatments for fibromyalgia include the development of large, multicenter, well-controlled clinical trials to test the efficacy of a variety of therapies. The results of the clinical trials will help to identify which patients might benefit from a particular treatment, whether that treatment approach is pharmacological, non-pharmacological or a combination of different therapies. The ultimate goal of fibromyalgia treatment is to develop an individualized treatment approach that takes into account the nature of the patient’s fibromyalgia symptoms and their severity, the level of function and stressors, and the presence of medical and psychiatric comorbidity. New developments in the pharmacological treatment of fibromyalgia Serotonin and norepinephrine reuptake inhibitors There is emerging evidence that fibromyalgia is associated with aberrant central nervous system processing of pain [1-4]. Although the American College of Rheumatology criteria for fibromyalgia [5] require tenderness in 11 out of 18 discrete regions, patients with fibromyalgia have increased sensitivity to pressure pain throughout the body. Fibromyalgia patients often develop an increased response to painful stimuli (hyperalgesia) and experience pain from normally nonnoxious stimuli (allodynia) [6]. Both hyperalgesia and allodynia reflect an enhanced central nervous system processing of painful stimuli that is characteristic of central sensitization [7]. Serotonergic and noradrenergic neurons are implicated in the mediation of endogenous pain inhibitory mechanisms through the descending inhibitory pain pathways in the brain and spinal cord [8-10]. Dysfunction in serotonin and norepinephrine in these pain inhibitory pathways may contribute to the central sensitization and hyperexcitability of the spinal Review Biology and therapy of fibromyalgia New therapies in fibromyalgia