Jakobsen 1992.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 40 Inclusion criteria: healthy women undergoing elective hysterectomy under GA Exclusion criteria: not reported Type of surgery: hysterectomy Baseline characteristics Intervention group (metoprolol) Age, mean (SD): 43 (± 15) years Control group (placebo) Age, mean (SD): 39 (± 2.2) years Country: Denmark Setting: single centre; hospital
Interventions	Intervention group (metoprolol) Randomized, n = 20; losses = 0; analysed, n = 20 (use of ITT analysis not reported) Details: 100 mg metoprolol orally with diazepam 15 mg, 1‐2.5 h before surgery Control group (placebo) Randomized, n = 20; losses = 0; analysed, n = 20 Details: placebo with diazepam 15 mg, 1‐2.5 h before surgery
Outcomes	Outcomes measured/reported by study authors: changes in catecholamine levels, haemodynamic variables, arrhythmias (type not specified), and perioperative blood loss, bradycardia (HR < 50 bpm), hypotension (MAP < 60 mmHg) Outcomes relevant to the review: hypotension, bradycardia
Notes	Funding/declarations of interest: not reported Study dates: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Randomized, double‐blind, placebo‐controlled trial; we therefore assumed that personnel were blinded
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	Study authors did not report prospective clinical trial registration or publication of a protocol. It was not feasible to effectively assess risk of reporting bias
Other bias	Low risk	Not detected