Miguel Rivero 1997

Methods	Randomised, double blind, placebo control, single and multiple oral dose phases. Duration of single dose phase 5 h. Baseline PI = ≥50/100 mm Self assessment at t = 0, 0.15, 0.30, 1, then hourly up to 5 h.
Participants	Orthopaedic surgery ‐ total hip replacement N = 106 M 48, F 58 Mean age 62 years
Interventions	Dipyrone 2 g IM, n = 35 Ibuprofen arginine 400 mg (oral), n = 36 Placebo, n = 35
Outcomes	PI: 100 mm VAS (no pain‐unbearable pain) PGE: standard 5 point scale Use of rescue medication Adverse events Withdrawals
Notes	Oxford Quality Score: R1, DB2, W1. Total = 4 Rescue medication allowed after 1 h
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	Low risk	"double dummy"