DARU Journal of Pharmaceutical Sciences123"Comparison of the analgesic profile and side effects of tramadol vs pethidine, following urologoical surgery "111114Mojtaba MojtahedzadehFarshad HashemianAtabak NajafiMohammad Reza RouiniMohammad K. AghamirHassan TavakoliOmid SoofiniaMohammad R. Khajavi20151006The optimization of pain management following surgery with minimal side effects, is one the major goals of surgical and medical teams. In this randomized double blind study, sixty ASA (American Society of Anesthesiologist) class I or II patients, undergoing urological surgery, were assessed to receive either pethidine or tramadol using a standard method for general anesthesia. Pain intensity was assessed by verbal rating, through a 4-step scaling system. Results of this investigation have revealed that the mean total drug administered in tramadol group were 244.53 + 56.95 mg and in pethidine group 176.78+42.99 mg respectively. There were no significant differences in analgesic effect, observed in either group during early hours following surgery, but after 8,12 and 16 hours significant differences were observed. Analgesic properties of tramadol were almost comparable with pethidine nevertheless; pethidine was superior in some extent. No significant differences in patient’s PaO2 were found, but PaCO2 at 1 and 4 hours after surgery had a greater retention in pethidine group. (Phttps://daru.tums.ac.ir/index.php/daru/article/view/212https://daru.tums.ac.ir/index.php/daru/article/download/212/212