Treatment of Chronic Pain with Drugs that Modulate Central Nervous System Serotonin and Norepinephrine

The perception of pain is the result of complicated physiological and psychological processes. Pain can be treated by interrupting peripheral inputs, or by modulation of pain signals in the central nervous system. One approach that has been particularly successful has involved use of drugs that increase activity in brain and spinal cord pathways that inhibit transmission of pain signals. Drugs that increase serotonin and norepinephrine (Serotonin Norepinephrine Reuptake Inhibitors - SNRIs) have been found to be effective. These drugs are known to have antidepressant activity, and are widely used to treat depression. Although there is overlap between pain and depression, the reason these drugs are effective for treatment of pain appears to result from a direct effect on pain pathways in the central nervous system. Mechanisms of action and clinical utility of SNRIs in treatment of chronic pain are reviewed.