EQUINE PAIN - USE OF NONSTEROIDAL ANTIINFLAMMATORY DRUGS AND ANALGESICS FOR ITS PREVENTION AND CONTROL

Pain is a condition caused by tissue damage in the horse and may inter fere with the ability to perform. Nonsteroidal anti-inflammatory drugs and corticosteroids reduce inflammation, swelling, and pain without s ignificant central nervous system (CNS) activity. In contrast opioid a nd ct, adrenoreceptor agonists may either markedly stimulate or depres s the brain. In contrast to many species, the horse may receive only m inor pain control with some opioids. Opioids may even increase CNS act ivity, as confirmed by electroencephalogram (EEG) analysis, potentiall y enhancing performance. Alpha(2) agonists in contrast predictably med iate CNS depression with little chance of racing performance enhanceme nt. The total amplitude of the EEG may be depressed up to 80% of contr ol levels. There are indications of additive or synergistic responses when both opioid and alpha(2) agonists are administered concurrently. CNS responses determined during concurrent detomidine-butorphanol admi nistration showed similar levels of EEG amplitude depression and frequ ency shifts. Neurologic evaluation can provide new evidence of the inf luence of injury and pain and the effect of operative procedures which may further mediate pain-evoked potentials. Efforts to combine analge sic and anesthetic management during the perioperative and postoperati ve periods in injured racehorses should provide a reduction in pain an d stress a with potentially earlier return to training.