Duloxetine for the treatment of fibromyalgia.

The underlying cause of fibromyalgia is not known, although dysfunction of serotoninergic and noradrenergic neurotransmitters appears to play an important role in the condition. Duloxetine is a newer and better tolerated dual antidepressant that does not induce muscarinic, histaminergic or adrenergic adverse reactions, and at the same time modulates and enhances the endogenous descending system that inhibits nociception. Duloxetine reduces pain symptoms in depression and other diseases and conditions, including fibromyalgia. Over 90% of the observed effect on pain is due to a direct analgesic effect rather than an indirect antidepressant effect. In clinical trials, pain reduction with duloxetine was not associated with its antidepressant and anxiolytic effects in patients with fybromialgia. A meta-analysis of four randomized, double-blind, placebo-controlled studies of duloxetine in the treatment of fibromyalgia showed it to be significantly superior to placebo in providing pain relief, reducing fatigue and improving physical and mental performance. The results of safety studies indicate that duloxetine is safe and well tolerated. Adverse effects tend to be mild, appearing more often at the start of therapy and decreasing or disappearing over the course of continued treatment.