Kaul 1996.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 3 groups, monoprophylaxis
Participants	Baseline characteristics Placebo (group A) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 80 Age (mean ± SD, median (IQR), median (range)): 37.73 ± 13.58 Weight (mean ± SD, median (IQR), median (range)): 56.68 ± 10.98 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 60/20/0/0 Gender (female in %): 51.25 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: balanced anaesthesia (N₂O, halothane, opioid) Duration of anaesthesia or surgery (in min; as mean or median): 117.2 Use of perioperative opioids (if yes, which?): 52.87 ± 19.88 mg pethidine intraoperative, 7.26 ± 1.38 mg morphine postoperative Type of surgery: gall bladder, gynaecological, orthopaedic, ophthalmological, ENT, miscellaneous Ondansetron (group B) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 81 Age (mean ± SD, median (IQR), median (range)): 37.58 ± 12.98 Weight (mean ± SD, median (IQR), median (range)): 57.96 ± 9.00 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 64/17/0/0 Gender (female in %): 55.56 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: balanced anaesthesia (N₂O, halothane, opioid) Duration of anaesthesia or surgery (in min; as mean or median): 116.6 Use of perioperative opioids (if yes, which?): 52.22 ± 14.41 mg pethidine intraoperative, 7.12 ± 1.75 mg morphine postoperative Type of surgery: gall bladder, gynaecological, orthopaedic, ophthalmological, ENT, miscellaneous Metoclopramide (group C) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 80 Age (mean ± SD, median (IQR), median (range)): 40.82 ± 13.80 Weight (mean ± SD, median (IQR), median (range)): 57.48 ± 12.01 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 66/14/0/0 Gender (female in %): 58.75 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: balanced anaesthesia (N₂O, halothane, opioid) Duration of anaesthesia or surgery (in min; as mean or median): 114.6 Use of perioperative opioids (if yes, which?): 56.12 ± 17.21 mg pethidine intraoperative, 7.35 ± 1.34 mg morphine postoperative Type of surgery: gall bladder, gynaecological, orthopaedic, ophthalmological, ENT, miscellaneous Included criteria: ASA I or II, adults younger than 65 years of age, undergoing an elective surgical procedure under general anaesthesia Excluded criteria: liver disease, renal impairment, pregnancy or lactation, known allergy to test drugs, neurological or endocrine abnormalities, history of emesis in the last 24 hours, requiring a nasogastric tube in the postoperative period Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear
Interventions	Intervention characteristics Placebo (group A) Dose: NA Time point of administration: 1 hour before induction of anaesthesia Route of administration: PO Rescue antiemetics (if yes, which?): at discretion of attending physician Ondansetron (group B) Dose: 8 mg Time point of administration: 1 hour before induction of anaesthesia Route of administration: PO Rescue antiemetics (if yes, which?): at discretion of attending physician Metoclopramide (group C) Dose: 10 mg Time point of administration: 1 hour before induction of anaesthesia Route of administration: PO Rescue antiemetics (if yes, which?): at discretion of attending physician
Outcomes	Nausea (0 to 24 hours) Outcome type: dichotomous outcome PONV (0 to 24 hours) Outcome type: dichotomous outcome Complete response (no PONV) in 24 hours Outcome type: dichotomous outcome Adverse events (general notes in the publication, 24 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: NATCO Pharma Laboratories supplied the drugs (ondansetron, metoclopramide, and placebo) for the study and help in conduct of the study Country: India Setting: NA Author's name: H.L. Kaul Institution: Department of Anaestesiology, India Institute of Medical Sciences, New Delhi Email: NA Address: Department of Anaesthesiology, all India Institute of Medical Sciences, New Delhi 110029 Language: English Duration of study: NA Trial registry number: NA Study's primary outcome: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: quote: "randomized". No further information on sequence generation provided
Allocation concealment (selection bias)	Unclear risk	Judgement comment: quote: "the drugs were enclosed in sealed identical envelopes marked A, B or C and administered to the patient by a nurse (who was not aware of the identity of the tablet) one hour before induction of anaesthesia" Not stated: "sequentially numbered, opaque, and sealed envelopes" (SNOSE)
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: no information on blinding of anaesthetists
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: no information on blinding of outcome assessors
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no missing outcome data
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no reference to a study protocol or trial registry number reported
Other bias	Unclear risk	Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear