Dejonckheere 2001.

Methods	Randomized, blinded, active‐controlled Medications administered on request in the PACU
Participants	Type of surgery: thyroidectomy Propacetamol group Entered/completing: 40/40 Age (mean, SD): 46.9 ± 2.1 Sex (male, %): 15 Tramadol group Entered/completing: 40/40 Age (mean, SD): 44.1 ± 1.8 Sex (male, %): 10
Interventions	Intervention: 2 g IV propacetamol Control: tramadol 1.5 mg/kg
Outcomes	Opioid consumption (morphine via PCA) Pain intensity (VAS)
Source of funding	SearΙe Continental Pharma Ιnc provided the trial drugs and statistical assistance
Were treatment groups comparable at baseline?	Yes: demographics; duration of surgery and anesthesia; intraoperative opioid use; nausea, vomiting, and drowsiness incidence pre‐interventions
Details of preoperative pain	Not reported ‐ participants with chronic opioid use were excluded
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	It appears that all participants completed the study and contributed data for each outcome at all relevant time points
Selective reporting (reporting bias)	Low risk	All outcomes from Methods section reported in Results section
Size	High risk	Fewer than 50 participants per arm of the study (40 propacetamol, 40 tramadol)