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THE EFFECT OF KETAMINE, DICLOFENAC AND THEIR COMBINATION ON FOUR MODELS OF INDUCED PAIN IN MICE

ABDULLAH M JAWAD --- ASMAA M HUSSAIN AL-ALI

Basrah Journal of Surgery مجلة البصرة الجراحية
ISSN: 16833589 Year: 2008 Volume: 14 Issue: 2 Pages: 12
Publisher: Basrah University جامعة البصرة

Abstract

Adjuvant analgesics are drugs that have weak or nonexistent analgesic action whenadministered alone, but can enhance analgesic action when co-administered with knownanalgesic agents. Ketamine, an anesthetic drug, is an adjuvant analgesic drug. Its use in doseslower than therapeutic doses might be important in the management of certain types of pain asneuropathic pain.The present study was performed to investigate the effects of subanesthetic doses of ketaminein four animal models of induced pain and to compare its effects with diclofenac sodium. It isalso intended to test the effectiveness of combining both drugs together in these animal modelsof pain.All experiments were performed on albino mice. Mice were evaluated for their responsivenessto noxious stimuli using four tests: tail-flick test, hot-plate test, formalin test and acetic acidinducedwrithing test. These effects were measured before and one hour after intraperitonealdrug administration. In some experiments, they were followed for 6 and 24 hours.We found that Ketamine, in subanesthetic doses, resulted in a significant analgesic effect in allthe four models of pain. It increased pain latencies in tail-flick test by 78% compared to preadministrationtime, and by 95% in hot plate test. It also decreased the number of lickings andbitings in formalin test by 41.9% and the number of abdominal writhing by 73.5%. Theseanalgesic effects represented around 60% of diclofenac effect in heat-induced pain models, butit is similar to diclofenac in the other two models. The enhancement of diclofenac analgesiceffect by ketamine ranged from 13.6% to 46% in the four tests.It is concluded that Ketamine in subanesthetic doses has a significant analgesic effectcomparable to diclofenac. It can enhance diclofenac effect by a margin not exceeding 50% ofdiclofenac effect. Much smaller doses of ketamine are required to be tested in the future.

Keywords

KETAMINE --- DICLOFENAC