Jahr 2012 Study 3, 65+.

Methods	Randomized, double‐blind, placebo‐controlled, multicenter repeated dose study evaluated up to 16 h postop Study entry occurred the day after surgery. Participants were required to have moderate postop pain for eligibility
Participants	Type of surgery: orthopedic (THA) Paracetamol group Entered/completing: 15/15 Age (mean, SD): 71.4 +/‐ 4.7 Sex (male, %): 9 (60%) Placebo Entered/completing: 12/12 Age (mean, SD): 68.4 +/‐ 3.5 Sex (male, %): 6 (50%)
Interventions	Paracetamol: 1000 mg IV administered at 0, 4, 10, 16 h Placebo
Outcomes	Primary: pain relief, pain intensity, total rescue medication, median time to rescue, SPID4, patient satisfaction Secondary: adverse events
Source of funding	Not mentioned
Were treatment groups comparable at baseline?	Yes: age, sex, weight, height, ASA classification, baseline PI
Details of preoperative pain	Not reported
Notes	Only published as an abstract. Study terminated early due to an issue unrelated to efficacy or safety of the interventions. Precipitates were found in the placebo vials.
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; reported as double‐blind
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis: WOCF if a participant was given rescue medication within the first 4 h after dosing LOCF if a participant missed the 4‐hour mean PI assessment and had not received rescue medication or if a participant terminated the study due to an adverse event Extrapolation if a participant missed one mean PI assessment and no rescue medication was received
Selective reporting (reporting bias)	Unclear risk	Reported all outcomes but no data presented for pain relief
Size	High risk	Fewer than 50 participants per arm of the study (15 paracetamol, 12 placebo)