ABSTRACT
Adjuvant analgesics have primary medical indications other than pain management, but may provide a hypoalgesic action in some patients. Antidepressants, neuroleptics, corticosteroids, anticonvulsants, sympatholytics, systemic local anesthetics, NMDA receptor antagonists, and central muscle relaxants can all be considered adjuvant analgesics. All of these classes of drugs enhance analgesia by interacting with a variety of receptors or altering nerve conduction processes implicated in pain modulating systems and signal generation or transmission. Many adjuvant analgesic drugs alter neurotransmission and conduction processes. Their use in chronic pain conditions may predispose the patient to enhanced effects of other classes of CNS depressant drugs. This cautions against the cavalier administration of CNS depressants in patients chronically medicated with adjuvant analgesics. To select and administer an adjuvant analgesic properly, doctor should be aware of the drugs clinical pharmacology. The following information about the drug is necessary: approved indication; unapproved indication in veterinary medical practice; pharmacokinetic features; and so on.
