['To demonstrate the efficacy and noninferiority of loading dose of celecoxib 200\u2003mg compared with 400\u2003mg in pain management after endoscopic nasal surgery.', 'A prospective randomized controlled study.', 'A university hospital.', 'Consecutive 120 patients undergoing endoscopic nasal surgery under general anesthesia were randomly assigned to three groups of 40 patients each, celecoxib 400\u2003mg, celecoxib 200\u2003mg, or a control group with no celecoxib.', 'Patients received different doses of celecoxib as described 1 hour before anesthesia. Two celecoxib groups received celecoxib 200\u2003mg every 12 hours until the fifth day after surgery.', 'Noninferiority could be claimed if the lower limit of the confidence interval (CI) for pain score difference was greater than -0.6. At 0, 6, and 48 hours after surgery, prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) to prostaglandin I2 (PGI2) ratios were measured from incision drainage and in plasma.', 'Estimated difference between two loading doses for pain scores over 5 days was 0.275 (95%CI -0.255 to 0.805, P\u2003>\u20030.05), indicating the noninferiority of celecoxib 200-400\u2003mg. Local PGE2 at 6 hours and 48 hours positively correlated with pain scores, with correlation coefficients 0.371 (P\u2003=\u20030.005) and 0.288 (P\u2003=\u20030.033). Systemic TXA2 to PGI2 ratios did not differ among groups.'] Is comparison of different loading dose of celecoxib on postoperative anti-inflammation and analgesia in patients undergoing endoscopic nasal surgery-200 mg equivalent to 400 mg?