Bunemann 1994.

Study characteristics
Methods	Study design: parallel‐group randomized controlled trial Sample size: 117 Country: Denmark Setting: secondary care Dates conducted: not reported Postoperative opioid used and delivery: IV pethidine Pain score collection: in recovery (unclear who) and 24 hour self‐report Concurrent postoperative analgesics: paracetamol
Participants	Inclusion criteria ASA 1 or 2 Minor orthopaedic surgery Exclusion criteria Allergy to NSAIDs Pregnancy NSAID treatment within 14 days Opioids Hypoglycaemics Sedatives Lithium Psychiatric drugs Peptic ulcer Age < 18 and > 60 years old
Interventions	Group TP (59 participants): naproxen 1100 mg one hour before surgery and placebo immediately after surgery Group PT (58 participants): placebo one hour before surgery and naproxen 1100 mg immediately after surgery
Outcomes	Postoperative pain (0‐100 mm VAS in PACU, discharge and at 24 hours) Analgesia consumption (paracetamol and pethidine consumption in PACU and at 24 hours) Side effects (no details reported on timing or actual side effects measured)
Notes	Funding: not reported Declarations of interest: not reported Authors contacted: no Other: pain scores estimated from median and interquartile range; analgesic consumption not included as not just opioid consumed
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details reported
Allocation concealment (selection bias)	Unclear risk	No mention
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐dummy placebo. Quote: "naproxen sodium 1100 mg 1 h before surgery and placebo immediately after surgery"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Six exclusions, although unclear which groups. Ten missing for 24‐hour data. Quote: "six had to be excluded; three because they did not have an operation and three because they did not have general anaesthesia".
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration
Other bias	Low risk	Similar baseline characteristics