Pereira 1986

Methods	Randomised, double blind, placebo control, single oral dose. Study duration 4 h Baseline PI = moderate or severe Self assessment at t = 0.15, 1, then hourly up to 4 h.
Participants	Orthopaedic surgery N = 85 M 57, F 28 Mean age 39 years
Interventions	Dipyrone 1 g, n = 28 Acetaminophen 1 g, n = 28 Placebo, n = 29
Outcomes	PI: standard 4 point scale (0‐3) PR: standard 5 point scale (0‐4) PGE: non‐standard 4 point scale Use of rescue medication
Notes	Oxford Quality Score: R1, DB2, W0. Total = 3 Rescue medication allowed after 2 h
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	Capsules were identical in appearance