Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Forest plot of comparison: ibuprofen 400 mg + high dose codeine versus placebo, outcome: 2.1 Participants with ≥ 50% pain relief.

Studies comparing ibuprofen plus codeine with placebo, with the outcome of at least 50% maximum pain relief over 4‐6 hours. Colour code: white ‐ ibuprofen 200 mg + codeine 15 mg; yellow ‐ ibuprofen 200 mg + codeine 30 mg; light pink ‐ ibuprofen 400 mg + codeine 25.6 mg; medium pink ‐ ibuprofen 400 mg + codeine 30 mg; red ‐ ibuprofen 400 mg + codeine 60 mg; blue ‐ ibuprofen 800 mg + codeine 60 mg.

Studies comparing ibuprofen plus codeine with same dose of ibuprofen, with the outcome of at least 50% maximum pain relief over 4‐6 hours. Colour code: darker yellow ‐ ibuprofen 200 mg + codeine 20 mg versus ibuprofen 200 mg; lighter yellow ‐ ibuprofen 400 mg + codeine 60 mg versus ibuprofen 400 mg.

Forest plot of comparison: ibuprofen + codeine (all doses) versus same dose of ibuprofen alone, outcome: 3.1 Participants with ≥ 50% pain relief.

Comparison 1 Ibuprofen 400 mg + high dose codeine versus placebo, Outcome 1 Participants with ≥ 50% pain relief.

Comparison 1 Ibuprofen 400 mg + high dose codeine versus placebo, Outcome 2 Participants with any adverse event.

Comparison 2 Ibuprofen + codeine (all doses) versus same dose of ibuprofen alone, Outcome 1 Participants with ≥ 50% pain relief.