Fibromyalgia syndrome (FM) is a condition of chronic and diffuse muscular pain affecting particularly middle aged women. The aetiology of FM is not completely understood and it is currently considered a disorder of pain regulation. The most efficacious compounds include the tricyclic drugs and mixed reuptake inhibitors. Recent works suggest that the anticonvulsant medications pregabalin and gabapentin are also effective. Moreover, two serotonin and norepinephrine-reuptake inhibitors-duloxetine and milnacipran show encouraging results in treating FM symptoms. The results of clinical trials of anti-inflammatory medications have been generally disappointing, but three RCTs have found that tramadol (with or without acetaminophen) is effective in FM.