Lahtinen 2002.

Methods	Randomized, double‐blinded, placebo‐controlled Medications administered immediately after arrival in the PACU
Participants	Type of surgery: cardiac Propacetamol group Entered/completing: unclear/40 Age (mean, SD): 59 ± 6 Sex (male, %): 85 Placebo group Entered/completing: unclear/39 Age (mean, SD): 58 ± 7 Sex (male, %): 90
Interventions	Intervention: 2 g propacetamol in 100 ml normal saline Placebo: 100 ml normal saline
Outcomes	Opioid consumption (oxycodone via PCA and rescue) Pain intensity at rest and during deep breath (VAS) Patient satisfaction (categorical)
Source of funding	Not reported
Were treatment groups comparable at baseline?	Yes: demographics; duration of anesthesia and surgery; intraoperative opioid use
Details of preoperative pain	Not reported
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers and a balanced design with a computer program
Allocation concealment (selection bias)	Low risk	Randomization/blinding performed in pharmacy
Blinding (performance bias and detection bias) All outcomes	Low risk	The propacetamol and placebo ampoules were supplied in identical packages. The code remained blinded until the end of the study.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	9/88 participants withdrew for various reasons ‐ unclear which arm participants withdrew from and if this was after receiving intervention
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, 39 placebo)