Moonla 2018.

Study characteristics
Methods	Study design: parallel‐group randomized controlled trial Sample size: 84 Country: Thailand Setting: secondary care hospital Dates conducted: February 2016 to May 2017 Postoperative opioid used and delivery: PCA morphine Pain score collection: not reported Concurrent postoperative analgesics: none
Participants	Inclusion criteria Aged 21–88 years old Not pregnant or lactating Fully conscious and able to agree with the study protocol Major spinal surgery (expected to be a long surgery) involving > 2 spinal levels or using spinal fixation devices Attended by a neurosurgeon with > 3 years experience in spinal surgery ASA 1‐3 Exclusion criteria < 50 kg Receiving any analgesic drug within 24 hours prior to surgery Liver impairment Renal impairment or signs of fluid retention Fluconazole within 1 week prior to surgery Hypersensitivity to parecoxib, sulfonamides, or other NSAIDs, including compounds contained in parecoxib Contraindication to parecoxib administration Contraindication to lorazepam use, anesthesia medications, and morphine
Interventions	Group Pre (42 participants): 40 mg parecoxib before skin incision and at 12 and 24 hours after the first dose Group Post (42 participants): 40 mg parecoxib at wound closure and at 12 and 24 hours after the first dose
Outcomes	Postoperative pain (0‐10 cm VAS every 2 hours for the first 8 hours after surgery and then every 4 hours for the next 16 hours thereafter) Morphine consumption (mg in 24 hours) Time to analgesia (not reported) Adverse events (nausea and vomiting, abdominal pain, flatulence, limb oedema, dizziness, drowsiness, and oliguria at 24 hours)
Notes	Funding: none reported Declarations of interest: "No potential conflict of interest relevant to this article was reported". Authors contacted: no Other: data taken from graphs and SD calculated from SEM
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Block randomization. Quote: "...block randomization sampling method"
Allocation concealment (selection bias)	Unclear risk	No mention
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐dummy placebo. Quote: "This study was a double‐blind trial. Each group received six doses of intravenous solution. All solutions were colorless, and each solution was given in a 2 mL volume, prepared by a nurse anesthetist who was not involved in the assessment and patient care before, during, and after operation".
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention
Incomplete outcome data (attrition bias) All outcomes	High risk	Large number of dropouts. Quote: "Because of incomplete data, 17 of 144 patients were excluded from the study; nine patients withdrew consent, five had surgical complications that required intervention, and three required prolonged postoperative mechanical ventilation".
Selective reporting (reporting bias)	Unclear risk	No protocol
Other bias	Low risk	Similar groups