Perez Garcia 2000.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Ondansetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 50 Received treatment (n): NA Analysed (n): 50 Age (mean ± SD, median (IQR), median (range)): NA Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/NA/0 Gender (female in %): NA Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (isoflurane, halothane, enflurane) Duration of anaesthesia or surgery (in min; as mean or median): NA Use of perioperative opioids (if yes, which?): NA Type of surgery: elective surgery (general surgery, gynaecological, ophthalmological, maxillofacial, other) Metoclopramide Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 50 Received treatment (n): NA Analysed (n): 50 Age (mean ± SD, median (IQR), median (range)): NA Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/NA/0 Gender (female in %): NA Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (isoflurane, halothane, enflurane) Duration of anaesthesia or surgery (in min; as mean or median): NA Use of perioperative opioids (if yes, which?): intraoperative fentanyl Type of surgery: elective surgery (general surgery, gynaecological, ophthalmological, maxillofacial, other) Included criteria: adult; ASA I, II, or III; scheduled for elective surgery under general anaesthesia with endotracheal intubation and administration of narcotic analgesic fentanyl Excluded criteria: received an antiemetic within 24 hours before surgery; with antecedents of nausea and/or vomiting due to kidney disease, liver disease, peptic acid, and stomach surgery; those who in the postoperative period received a prophylactic antiemetic treatment equal to or different from the drugs studied Pretreatment: baseline characteristics (age, weight, ASA): unclear. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): unclear
Interventions	Intervention characteristics Ondansetron Dose: 4 mg Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): NA Metoclopramide Dose: 10 mg Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): NA
Outcomes	Vomiting (0 to 24 hours) Outcome type: dichotomous outcome Vomiting (12 to 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: NA Country: Mexiko Setting: inpatient, single‐centre Author's name: Austreberto Pérez Garcia Institution: Departemento de Anestesiologia, Hospital General de Zona 1 del IMSS, Tapachula Chiapas Email: austreberto@acnet.net Address: Andador Cafetales Manzaneros 1 Casa 3 Fracc. Santa Clara, Tapachula Chiapas CP 30788 Duration of study: NA Language: Spanish (translated by Insa Backhaus) Study's primary outcome: NA Trial registry number: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: quote: "..prospective, randomized, triple‐blind..." No further information on sequence generation provided
Allocation concealment (selection bias)	Unclear risk	Judgement comment: no statement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: quote: "..prospective, randomized, triple‐blind..." Insufficient information on blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Judgement comment: quote: "the evaluator did not know which medication had been administered"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Judgement comment: no reasons for exclusion described for 3 participants
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): unclear. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): unclear