Comparison 1. Dexmedetomidine versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Amount of 'rescue' opioid 3 hours after surgery (intravenous morphine equivalents)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
2 Amount of 'rescue' opioid 24 hours after surgery (intravenous morphine equivalents)	4		Mean Difference (IV, Random, 95% CI)	Totals not selected
3 Postoperative pain 3 hours after surgery (VAS 0‐100)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
4 Postoperative pain 6 hours after surgery (VAS 0‐100)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
5 Postoperative pain 12 hours after surgery (VAS 0‐100)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
6 Postoperative pain 24 hours after surgery (VAS 0‐100)	4		Mean Difference (IV, Random, 95% CI)	Totals not selected
7 Postoperative nausea and vomiting (PONV)	3		Risk Ratio (IV, Random, 95% CI)	Totals not selected