Forbes 1986.

Methods	Randomised, double blind, 5 parallel groups. Single oral dose Medication administered when baseline pain reached a moderate to severe intensity Pain assessed at baseline, then hourly up to 12 hours
Participants	Surgical removal of impacted third molars N = 198 M = 79, F = 119 Mean age 25 years
Interventions	Codeine 60 mg, n = 44 Naproxen sodium 550 mg, n = 38 Naproxen sodium + codeine 550/60 mg, n = 38 Aspirin 650 mg, n = 36 Placebo, n = 42
Outcomes	PI: standard 4 point scale PR: standard 5 point scale PGE: standard 5 point scale Time use of rescue medication Adverse events: any, serious Withdrawals
Notes	Oxford Qualtiy Score: R2, DB2, W1. Total = 5
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Computer assigned patient numbers "using a random‐numbers generator"
Allocation concealment?	Unclear risk	Not described
Blinding? All outcomes	Low risk	"All tablets were identical in appearance"