Intrathecal Ketorolac Injection in Albino Rats; Pharmacological and Histological study

Introduction: Ketorolac tromethamine is a potent injectable non-steroidal antiinflammatory drug (NSAID). Ketorolac provides successful analgesia after intrathecal or epidural injection. It is frequently used to manage post-operative pain, cancer pain, and arthritis either intrathecally, or intramuscular. However, its long term administration could induce renal toxicity and/or gastro-intestinal ulceration. Aim of the study: The aim of this study was to assess the analgesic potency of ketorolac after intrathecal injection. Also, we aimed to study the histological effect of ketorolac on the spinal cord and the duodenum after treatment in an animal model. Methods: 40 adult male albino rats, weighing 250-350 gm, were used and divided into 4 groups, 10 rats each. Group S (control) received 10μl normal saline intrathecally, group K50 received 50μg ketorolac intrathecally, group K50 + omeprazole (proton pump inhibitor) received 50μg ketorolac intrathecally plus 0.2 mg omeprazole orally, and finally, group K100 received 100μg ketorolac intrathecally. All animals were treated for four successive days. Result: The rat tail flick latency was longer in K50, K50 + omeprazole, and K100 groups when compared to normal control (P = 0.002). Also, the hind-paw withdrawal latency was longer in treated groups when compared to those of the control group (P = 0.0001). Moreover, K50 group showed decreased phase II response by 61%, K50 + omeprazole group showed decreased phase II by 62%, while K100 group showed decreased it by 76%. Histological examination revealed no changes in the spinal cord of all treated animals. Also, examination of the duodenum showed normal duodenal mucosa in group K50 and those of group K50 + omeprazole. On the other hand, cellular infiltration as well as destruction of the mucous acini have been noticed in the duodenum of K100 group. Conclusion: Ketorolac could be a good alternative drug used intrathecally to manage pain. Key word; Ketorolac, analgesics, intrathecal, rats