O'Hanlon 1996.

Study characteristics
Methods	Study design: parallel‐group randomized controlled trial Sample size: 60 Country: Northern Ireland Setting: secondary care Dates conducted: not reported Postoperative opioid used and delivery: cyclimorph or co‐codamol Pain score collection: self‐report Concurrent postoperative analgesics: paracetamol PRN (as part of co‐codamol)
Participants	Inclusion criteria ASA 1 and 2 Diagnostic laparoscopy Exclusion criteria Hypersensitivity to NSAIDs Peptic ulcer disease Asthma Renal impairment Concurrent NSAID medication
Interventions	Group 1 (20 participants): PO piroxicam 20 mg 2 hours before surgery and placebo at induction and one hour postoperatively Group 2 (20 participants): PO piroxicam 20 mg at induction and placebo 2 hours before surgery and one hour postoperatively Group 3 (20 participants): PO piroxicam 20 mg one hour postoperatively and placebo 2 hours before surgery and at induction
Outcomes	Time to analgesic request (minutes) Postoperative pain (0‐10 cm VAS on admission to the recovery ward, at 1, 2, 4, 8 and 24 hours) Analgesic consumption (cyclimorph and paracetamol/codeine during postoperative period)
Notes	Funding: not reported Declarations of interest: not reported Authors contacted: no Other: pain score data extracted from graph. Group 1 and 2 combined for the pre‐emptive group. Pain score at 2 hours included to allow postoperative dosing to take effect
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details. Quote: "...in a randomised double blind manner"
Allocation concealment (selection bias)	Unclear risk	No mention
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Triple‐dummy placebo used. Quote: "...in a double blind manner, either 20 mg piroxicam or placebo in the "melt" form at the following times; two hours pre‐operatively, immediately before induction of anaesthesia or one hour postoperatively"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention
Incomplete outcome data (attrition bias) All outcomes	Low risk	All patients analysed
Selective reporting (reporting bias)	Unclear risk	No protocol
Other bias	Low risk	Similar baseline characteristics. Quote: "...patients in the three treatment groups were equally matched with respect to age, height and weight".