Biochemical aspects of chronic pain and its relationship to treatment.

This review presents an overview of the neurotransmitters and neuromodulators involved in acute and chronic pain. Although there is little evidence that the neuronal pathways differ in the two types of pain, it is clear that different transmitters or receptor types are involved in hyperalgesia and chronic pain. While most attention has been focussed on spinal processes, it is apparent that some types of chronic pain have both a peripheral and a supraspinal component. The presently available drugs are probably adequate for acute pain, but the treatment of chronic pain may need to be tailored to the individual patient.