['This multicentre, double-blind, placebo-controlled study compared the opioid-sparing effectiveness and clinical safety of parecoxib sodium over 48 h, in 195 postoperative patients after routine total knee replacement surgery.', 'Elective total primary knee arthroplasty was performed under spinal anaesthesia, with a single dose of spinal bupivacaine 10-20 mg, and intraoperative sedation with midazolam 0.5-1.0 mg i.v., or propofol <6 mg kg(-1)h(-1). Patients were randomized to receive either parecoxib sodium 20 mg twice daily (bd) i.v. (n=65), parecoxib sodium 40 mg bd i.v. (n=67), or placebo (n=63) at the completion of surgery, and after 12, 24, and 36 h. Morphine (1-2 mg) was taken by patient-controlled analgesia or by bolus doses after 30 min.', 'Patients receiving parecoxib sodium 20 mg bd and 40 mg bd consumed 15.6% and 27.8% less morphine at 24 h than patients taking placebo (both P<0.05). Both doses of parecoxib sodium administered with morphine provided significantly greater pain relief than morphine alone from 6 h (P<0.05). A global evaluation of study medication demonstrated a greater level of satisfaction among patients taking parecoxib sodium than those taking placebo. Parecoxib sodium administered in combination with morphine was well tolerated. However, a reduction in opioid-type side-effects was not demonstrated in the parecoxib sodium groups.'] Does parecoxib sodium have opioid-sparing effects in patients undergoing total knee arthroplasty under spinal anaesthesia?