Nineteen studies (n=1,606), including 26 comparisons, were included in the review.
Overall, the included studies were of a high quality (median quality score 4 out of 5; range: 2 to 5).
Consumption of supplementary opioids (19 studies).
Supplementary opioid consumption (0 to 24 hours) was significantly reduced by an average of 35% (range: 14 to 100) with COX-2 inhibitors.
Opioid-related adverse events. No significant difference was found between COX-2 inhibitors and placebo for nausea (RR 1.04, 95% CI: 0.92, 1.18), vomiting (RR 0.91, 95% CI: 0.74, 1.12), constipation (RR 0.86, 95% CI: 0.67, 1.07), sedation (RR 0.94, 95% CI: 0.63, 1.41), pruritis (RR 0.84, 95% CI: 0.57, 1.24) or urinary retention (RR 1.20, 95% CI: 0.50, 2.91). The occurrence of dizziness was significantly higher in those treated with COX-2 inhibitors than those treated with placebo (RR 0.70, 95% CI: 0.50, 0.96). The corresponding NNT was 33 (95% CI: 17, 125).
Overall, the reporting of adverse events was poor.