Winter 1983.

Methods	Single‐centre, randomised, double‐blind, placebo‐controlled, parallel‐group study Single oral dose administered after the onset of moderate or severe pain Duration: 4 h, with assessments at baseline, 0.5, 1, 2, 3, and 4 h post dose
Participants	Oral surgery, including multiple bony impactions, single bony impaction, single tissue impaction, multiple tissue impactions, multiple extractions, alveolectomy, and difficult (complicated) extraction Participants were 16 to 75 years of age N = 167 (164 for efficacy) M 67, 97 Mean age 27 years
Interventions	Paracetamol 1000 mg + caffeine 130 mg, n = 40 for efficacy Paracetamol 1000 mg, n = 41 for efficacy Caffeine 130 mg, n = 42 for efficacy Placebo, n = 41 for efficacy No analgesic agent for ≥ 4 h before taking test medication
Outcomes	PI: standard 4‐point scale PR: standard 5‐point scale PGE: standard 5‐point scale Withdrawals and dropouts Serious adverse events
Notes	Oxford Quality Score: R1, DB2, W1. Total = 4/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method used to generate random sequence not described
Allocation concealment (selection bias)	Unclear risk	Method not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"identically appearing 2‐capsule doses"
Size	High risk	< 50 participants in relevant treatment arms