Muhammad 2000.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 3 groups, monoprophylaxis
Participants	Baseline characteristics Tropisetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 16 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/0/0 Gender (female in %): NA Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (halothane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): NA Use of perioperative opioids (if yes, which?): NA Type of surgery: mini‐laparotomy cholecystectomy Metoclopramide Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 16 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/0/0 Gender (female in %): NA Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (halothane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): NA Use of perioperative opioids (if yes, which?): NA Type of surgery: mini‐laparotomy cholecystectomy Placebo Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 18 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/0/0 Gender (female in %): NA Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (halothane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): NA Use of perioperative opioids (if yes, which?): NA Type of surgery: mini‐laparotomy cholecystectomy Included criteria: few or no other risk factors for anaesthesia, ASA I and II, between 22 and 71 years of age with cholelithiasis but no obvious bile duct pathology, had mini‐laparotomy cholecystectomy Excluded criteria: NA Pretreatment: baseline characteristics (ASA): no; (age, weight): unclear. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): unclear
Interventions	Intervention characteristics Tropisetron Dose: 2 mg Time point of administration: immediately after induction Route of administration: IV Rescue antiemetics (if yes, which?): metoclopramide 10 mg Metoclopramide Dose: 10 mg Time point of administration: immediately after induction Route of administration: IV Rescue antiemetics (if yes, which?): metoclopramide 10 mg Placebo Dose: saline Time point of administration: immediately after induction Route of administration: IV Rescue antiemetics (if yes, which?): metoclopramide 10 mg
Outcomes	PONV (0 to 24 hours) Outcome type: dichotomous outcome
Identification	Sponsorship source: NA Country: Pakistan Setting: inpatient, single‐centre Author's name: Syed Razi Muhammad Institution: Department of Surgery, Baqai Medical University, Karachi Email: NA Address: 51, Deh Tor, Gadap Road, Near Toll Plaza, Super Highway P.O Box No 2407, Karachi ‐ 74600, Pakistan Duration of study: NA Language: English 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	Quote: "all patients were randomised to receive immediately after induction one of the following three: Injection Tropisteron 2mg" Judgement comment: no 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: no statement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: no statement
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 (ASA): no; (age, weight): unclear. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): unclear