Cooper 1982.

Methods	Randomised, double blind, 6 parallel groups. Single oral dose Medication administered when baseline pain reached a moderate to severe intensity Pain assessed at baseline then hourly to 4 hours
Participants	Surgical removal of 1 to 4 impacted third molars N = 249 M = 83, F = 166 Mean age 23 years
Interventions	Codeine 60 mg, n = 41 Ibuprofen 400 mg, n = 38 Ibuprofen + Codeine 400/60 mg, n = 41 Aspirin 650 mg, n = 38 Aspirin/codeine 650mg/60 mg, n = 45 Placebo, n = 46
Outcomes	PI: standard 4 point scale PR: standard 5 point scale PGE: standard 5 point scale Use of rescue medication Adverse events Withdrawals
Notes	Oxford Qualtiy Score: R1, DB2, W1. Total = 4 Rescue medication allowed after 1 hour
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Not described
Allocation concealment?	Low risk	Pharmaceutical company held randomisation code and packaged bottles, which were identified by sequential code number only
Blinding? All outcomes	Low risk	tablets "appeared identical for every patient"