Fig. 2. Twenty-four–hour morphine consumption (in milligrams). A weighted mean difference (WMD) less than 0 indicates less morphine consumption with active compared with control. When the 95% confidence interval (CI) does not include 0, the difference is considered statistically significant. COX-2 inhibitor = 200 mg celecoxib,a 50 mg rofecoxibb; multiple high dose = valdecoxib and parecoxib 40 mg/12 h and parecoxib 40 mg/6 h; multiple low dose = valdecoxib and parecoxib 20 mg/12 h; NSAID = nonsteroidal antiinflammatory drug.