Study Proposal - A Randomized Double-blinded Study Comparing Adding Etoricoxib Versus Placebo to Female Patients With Fibromyalgia-analysis of Organic and Psychiatric Measures

The fibromyalgia syndrome (FMS) is an ill-defined clinical disorder characterized by widespread pain and diffuse tenderness which is assessed at specified anatomical locations. The FMS is 10 times more common in females, and its prevalence in the community increases from two percent at age 20 to eight percent at age 70. Although the American College of Rheumatology (ACR) has defined classification criteria for the diagnosis of the FMS its' pathogenesis remains vague. Diffuse and persistent musculoskeletal pain, consistent with the mentioned ACR criteria have also been reported among patients with other ill defined medical conditions such as migraines, chronic fatigue pain, myofascial pain, irritable bowel syndrome which presentation often overlaps with the FMS.

There are mounting data supporting an overlap between the FMS and psychiatric conditions including depression, panic disorders and anxiety. For example, a lifetime history of major depression has been reported in 50% to 70% of patients with FMS and current depression was detected in 18% to 36% of patients with the FMS. This association has been questioned raising the possibility that this high prevalence reflects the long term outcome of coping with chronic disabling pain and disability.

Anti-depressants are the corner stone of therapy in FMS. Benzodiazepines and recent experience with melatonin has been implicated in order to alleviate sleep disturbances that are so often encountered among patients with this disorder. Nevertheless, patients with the FMS often need therapeutical medications in order to ease acute exacerbations of diffuse pain which are often provoked by mental or physical stressors.

Non-steroidal anti-inflammatory drugs (NSAIDs), COX-2-selective agents and acetaminophen are often used by a large number of FMS patients seeking a relief of acute pain. However, numerous studies have failed to confirm their effectiveness as analgesics in FMS, although there is limited evidence that patients may experience enhanced analgesia when treated with combinations of NSAIDs and other agents.

We believe that successful relief of diffuse pain may sever the bond tying pain and increased anxiety which is so characteristic in these patients. Furthermore, a clinical path that underlines the importance of pain relief may ensure the adherence and compliance that are needed to other elements of the therapeutical multidimensional approach in FMS and may be even improve psychiatric comorbidity that stem from the chronic non relenting pain.