Comparison between the analgesic effect of Tizanidine, Diclofenac and Gabapbentin on experimentally induced acute and chronic pain in male albino rats

Abstract

Background: Pain is an unpleasant sensation experienced when tissues are damaged. Therapeutic management of pain requires consideration of many factors due multiplicity of etiopathogenesis. Objectives: The present study was designed to assess and compare the analgesic effects of gabapentin, diclofenac and tizanidine as well as their combinations in acute and chronic pain. Methods: 128 rats were randomly allocated into two main equal categories; one for acute inflammatory and other for chronic neuropathic pain study. The acute category was divided into 8 equal groups; control, carrageenan, diclofenac, gabapentin, tizanidine, gabapentin-diclofenac, gabapentintizanidine and tizanidine-diclofenac groups. Acute inflammatory pain was induced by carrageenan injection in the animals paw. In the chronic category neuropathic pain was induced by right sciatic nerve ligation except for control and sham groups. This category was divided into; control, sham, gabapentin, tizanidine, gabapentin-diclofenac, gabapentin-tizanidine and tizanidinediclofenac groups. The mean reaction time was assessed in all groups. Results: In acute pain the three drugs and their combinations had significant analgesic effects. Tizanidine potentiated the analgesic effects of diclofenac and gabapentin. In chronic neuropathic pain diclofenac and gabapentin had significant analgesic action while, tizanidine had no analgesic effect. Conclusion: Tizanidine didn't show analgesic effect on chronic pain but potentiated the analgesic effect of gabapentin and diclofenac in acute pain model.