BACKGROUND The agonizing pain of patients with ureteric colic on presentation to emergency department requires effective analgesia to be delivered in the shortest feasible time. The most common analgesics prescribed for ureteric colic include non steroidal anti inflammatory drug, opioids and paracetamol. The choice is based on the evidence of its effectiveness as well as the logistics involved in the rapid delivery of the drug. Many trials comparing NSAID and opioids have been inconclusive, and there were only limited studies, which compare the effectiveness of IM diclofenac to IV tramadol. This study was conducted to develop conclusive evidence regarding the choice of initial analgesia in patients presenting with ureteric colic to the ED. OBJECTIVES To compare the effectiveness of opioids and Non Steroidal Anti- inflammatory drugs as analgesic for the management of patients presenting with ureteric colic in the emergency department. METHODS Study design: Prospective observational study; Study period: 1 year ; Study setting: Emergency Department Government Medical College Kozhikode Study population: Patients (both males and females) aged 18 years or older and younger than 65 years who presented with ureteric colic of intensity on Numerical pain Rating Scale (NRS 0-10) of 5 or more in the emergency department . Sample size: 91 in each group. STUDY PROCEDURE Informed written consent will be obtained from all study objects/ legal guardian. Study will be conducted in those patients, who present to the emergency department with flank pain and having a definitive diagnosis of ureteric calculi by standard criteria. Patients medical history will include: - Characteristics of pain, intensity of pain on NRS, abnormalities of major organ systems, previous adverse experience with any analgesia, drug allergies, current medications, potential drug interactions, any co morbidities. Patients will undergo a focused physical examination, including vital signs. After the diagnosis of renal calculi has been made by standard clinical or imaging modalities, the treating physician will resort to one of the two modalities- 1) Deep intramuscular injection of NSAID – diclofenac75mg 2) Intravenous injection of opioids – tramadol50mg. No additional analgesia will be administered for 30 minutes after administration of trial drug. Both treatment groups will receive equivalent treatment with the exception of analgesia allocated. Reduction in at least 50% of initial pain will be considered as effective pain reduction. RESULTS The desired outcome (reduction in the initial pain ≥50% at 30 minutes) was observed in 49 patients (53.8%) in the diclofenac group and 42 (46.2%) patients in the tramadol group with a p value of 0.299, which indicated that there is no remarkable difference between both the drugs in its efficacy to perform as an analgesic in ureteric colic. Even though there is no statistical difference, the adverse events were lower in diclofenac group than the tramadol group. CONCLUSION Intravenous tramadol is equivalent to intramuscular diclofenac for the relief of acute ureteric colic pain, after 30 minutes of administration of drug. There was no statistically significant difference in the development of adverse events between both the groups.