SANTOS, R. S. T. dos. Avaliação da inibição da atividade das ciclooxigenases 1 e 2 e da eficácia analgésica da dipirona em equinos. [Evalution of ciclooxygenases 1 and 2 and the analgesic efficacy of dipyrone in horses]. 2017. 107 f. Dissertação [Mestrado em Ciências] -Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2017. The pain control in animals has been the subject of numerous studies nowadays, both for humanitarian reasons, and for the influence that
... he influence that uncontrolled pain exerts on the physiological parameters of all animal species, which invariably causes harm to the welfare and productive ratings of the animals, whether they are production, sport or company animals. Non-steroidal anti-inflammatory drugs (NSAIDS) are the most commonly used drugs in horses, but may cause several side effects, including gastritis, or aggravating a preexisting condition, as it inhibits cyclooxygenase 1, which is the main responsible enzyme for producing not only inflammatory mediators, but also the stomach protective layer. Although dipyrone is not a classic NSAID, it may also promotes the inhibition of COX-1, already proven in humans and rats. Therefore, the present study aimed to evaluate the effect of intravenous administration of dipyrone at the dose of 15mg/kg, every 12 hours, in 12 Arabian horses, regardless of sex or age, for 24 hours. It was evaluated the concentrations of prostaglandin E 2 and thromboxane B 2 at basal times (TB, prior to the administration of dipyrone) and so on 2 (T2), 8 (T8), 12 (T12) and 24 (T24) hours later after the administration of dipyrone. In the second phase of the study, the assessment was conducted to evaluate the analgesia provided by dipyrone in 15 horses submitted to elective orchiectomy procedure, in which one of the groups received, postoperatively, dipyrone 15mg/kg, every 12 hours, and the other group received flunixin meglumine 1.1 mg/kg every 24 hours, both intravenously. Dipyrone promoted inhibition in COX-1 of 97.76% ± 2.02 in T2 (P<0.0001) and did not induce inhibition in COX-2, although it was effective as the sole analgesic for elective orchiectomy in healthy horses, and may be an option for mild to moderate pain management in horses.