Preoperative administration of analgesics may prevent or reduce hyperalgesia and inhibit inflammation and pain by reducing the synthesis of prostaglandins in response to surgical injury. We evaluated in this placebo-controlled study the analgesic efficacy and safety of single doses of parecoxib sodium (20, 40, and 80 mg IV) when administered before oral surgery. Efficacy assessments were recorded during the 24-h period after completion of surgery. All doses of parecoxib sodium were consistently and significantly superior to placebo as measured by time to rescue medication, proportion of patients requiring rescue medication, patient's global assessment, and pain intensity. There were no significant differences between the Parecoxib Sodium 40- and 80-mg groups, suggesting that the analgesic effect of preoperatively administered parecoxib sodium reaches a plateau at 40 mg in this model. Forty-eight percent of the Parecoxib Sodium 40-mg group required rescue medication in the 24-h study period, compared with 93% of patients in the Placebo group. Overall, there were fewer adverse events in parecoxib sodium-treated patients compared with placebo. These findings suggest that preoperative administration of parecoxib sodium, the injectable prodrug of the cyclooxygenase-2 specific inhibitor valdecoxib, is effective, safe, and well tolerated for treating postoperative pain.