[ comparison effects of analgesics flunixin meglumine and ketoprofen in pain induced by peroxynitrite in guinea-pigs]

ABSTRACT

Non steroidal anti inflammatory drugs [NSAIDs] are widely used to reduce inflammation, pain and fever. The present study was organized to induce an experimental inflammation in an animal model, using a putative biological oxidant, Peroxynitrite [ONOO] and to study the effects of Flunixin meglumine and Ketoprofen on the pressure-induced pain. For this purpose, 24 male guinea pigs were divided into 4 groups each consisting of 6 animals. Three groups [groups 2, 3 and 4] were injected Peroxynitrite and one group [the first control] received physiological salt solution subcutaneously in the paw. After induction of a local inflammatory response, Flunixin meglumine [1mg/kg] and Ketoprofen [2 mg/kg] were injected to the second and third groups, 5 times with 12h intervals. The first and the fourth groups were injected saline solution in the same manner. Pressure analgesiometry was performed before and 1 hour after injections. The animals in all 3 groups treated with Peroxynitrite demonstrated an increased sensitivity to painful pressure [P<0.05]. Both NSAIDs decreased the pain sensation dramatically after the 1[st] and the 2[nd] injections but, not after the 3[rd], 4[th] and the 5[th] injections. The study suggested that NSAIDs may be helpful in reducing pressure-induced pain in animal model in early hours of the treatment, whereas the effect subsides over time and ends up after a few days. This effect may be of importance in humans who receive these kinds of drugs for a long period as they may not be effective in reducing pain after a while