0,1,2,3,4,5,8,9,10,11,12,18 and 24 hrs among the three groups were statistically not significant. The increase observed at 6 and 7 hrs in tramadol and fentanyl groups compared with buprenorphine group was statistically significant which can be explained based on shorter duration of action of tramadol and fentanyl leading to wearing of the analgesic effect. Respiratory rate showed no significant changes at 0, 1, 2, 3, 4, 5, 8, 9, 10, 11, 12, 18 and 24