Main variables of analgesic effectiveness 25 h after discectomy. (a) Average pain score, (b) morphine consumption, and (c) composite opioid-related SDS. Patients treated with ‘perioperative parecoxib’ had significantly lower pain scores and SDS scores, and required less morphine compared with both placebo and postoperative parecoxib treatment. Means (sem) of 320 patients. ^#P<0.005 vs placebo, *P<0.05 vs postoperative parecoxib, ⁺P<0.01 vs placebo.