Objectives: Postoperative pain is one of the Leading Postoperative problems and often leads to many other complications. This study compared the efficacy of pentazocine and tramadol in the management of Postoperative pain following major abdominal surgery. The incidence of complications and their effects on average time spend in the recovery room were also studied. There are different modalities of managing postoperative pain; however systemic opioids are regarded as the gold standard in the relief of moderate to severe postoperative pain. The readily available opioids are tramadol and pentazocine therefore the result of this study will help guide the choice between tramadol and pentazocine However potent analgesics like morphine and pethidine are not available easily. Design: Randomized double blind study in which both the researcher and the patients were not aware of grouping and identity of interventions (drugs given). Methodology: The study population consist of 80 patients aged between 20 to 65 years with ASA class I or II scheduled for major abdominal surgery. After approval by the ethical committee the study population was randomly divided into to groups with 40 patients in each sub group.

• Group A (pentazocine)
• Group B (Tramadol)

At induction each patient was given analgesic in labeled syringes A or B according to the group of randomization and all patients had balanced general anaesthesia with endotracheal intubation. At the end of the operation, following reversal of the residual muscle paralysis and the recovery of consciousness and muscle power, patients were extubated and transferred to the recovery room. Visual analogue scale (VAS) was used to assess pain and labeled analgesic syringes that correspond to the one given at induction were given on request at the recovery room. When VAS was ≥4 and the frequency at which they were given was recorded. Results: The groups were comparable in respect to demographic characteristics. The mean time from administration of study medication at induction to first analgesic request was prolonged in group B, 3.2± 0.21 hours compared to 2.4 ± 0.08 in group A (P value of 0.003). The mean VAS score over three hours in the recovery room in group A of 8.08±1.06 was also much higher than that for group B (6.14 ±0.86) (P = 0.001). The mean frequency of analgesics administration in group A; 2.0 ± 1.0 was also higher than that for group B, 1.0 ± 0.5 with P value of 0.01 which was statistically significant. A total of 22 patients (60%) in group B as against 5(14%) in group A had nausea in the recovery room (P value = 0.02). Two (6%) patients in group A and 19 patients (52%) in group B vomited. This was statistically significant with a P value of 0.01. Conclusion: With these results, we conclude that tramadol was more effective compared to pentazocine in the management of postoperative pain though with a higher incidence of nausea and vomiting.