Fibromyalgia (FM) is a chronic pain condition, with auxiliary symptoms, such as sleep disturbances and fatigue. Although many of the mechanisms of action targeted by the drugs used to treat FM have been focused to the management of single symptoms, drugs (e.g. pregabalin, duloxetine) have now been identified that demonstrate a multidimensional effect. However, such drugs often fail to demonstrate acceptable efficacy in the majority of the patient population. Thus, the mechanisms of action of the drugs studied as treatments for FM are either identifying subgroups within the pathophysiology of the condition or suggesting that a mechanism of action that will offer universal efficacy has, as yet, to be identified.