• Fibromyalgia is characterized by a range of symptoms that include muscle pain, fatigue and sleep disorders. Anxiety and depression are often also present. The cause is unknown. More women than men are affected;
• The following review focuses on differential diagnoses and available treatments for fibromyalgia, based on a review of the literature using the standard Prescrire methodology;
• Fibromyalgia is mainly diagnosed by excluding other possibilities. The principal differential diagnoses are rheumatic involvement of the spine, systemic inflammatory disorders, and hypothyroidism. Unlike these other conditions, fibromyalgia is not associated with radiological or laboratory abnormalities;
• Paracetamol has not been compared with other treatments in fibromyalgia. Nonsteroidal antiinflammatory drugs have no specific effect;
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• The only two trials assessing tramadol showed little effect; in one study the average pain score was 53 mm in the tramadol group versus 65 mm in the placebo group, on a scale ranging from 0 to 100 mm. The adverse effects of tramadol are those of opiates in general, mainly nausea and dependence. Tramadol interacts with numerous other drugs;
• The efficacy of tricyclic antidepressants is also difficult to quantify. Their limited superiority over placebo lasts no more than a few months. The efficacy of selective serotonin reuptake inhibitor antidepressants (fluoxetine, paroxetine and citalopram), serotonin and nonadrenaline reuptake inhibitors (duloxetine and milnacipran) is even less well established. Duloxetine has been tested in four placebo-controlled trials with unconvincing results;
• Pregabalin and gabapentin, two antiepileptic drugs, appear to be more effective than placebo but have only been tested in short-term trials. In one trial 44% of patients in the pregabalin group said they felt better after 13 weeks versus 35% of patients in the placebo group. However, adverse effects are frequent and sometimes troublesome (drowsiness, dizziness, nausea, weight gain). In clinical trials, 19% to 33% of patients stopped treatment due to adverse effects after 13 weeks, depending on the dose of pregabalin;
• Assessments of non-drug treatments in this setting are generally mediocre. The best-assessed alternative therapies (acupuncture and physical exercise) only have a limited effect;
• In practice, when a patient presents with symptoms compatible with fibromyalgia, the first step is to rule out a treatable condition. Quality of life may be improved by first acknowledging that the pain is real, and possibly by providing psychological, medical, social and occupational support. The limited efficacy of available drugs, and their potential adverse effects, should be discussed with the patient.
Source: Prescrire International, Aug 2009;18(102):169-73. PMID: 19746561, no author listed.