Semira 2013.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 3 groups, monoprophylaxis
Participants	Baseline characteristics Ondansetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 30 Received treatment (n): 30 Analysed (n): 30 Age (mean ± SD, median (IQR), median (range)): 42.8 ± 8.2 Weight (mean ± SD, median (IQR), median (range)): 60.4 ± 7.1 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 24/6/0/0 Gender (female in %): 70 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (N₂O/isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 75.2 Use of perioperative opioids (if yes, which?): NA Type of surgery: laparoscopic cholecystectomy Dexamethasone Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 30 Received treatment (n): 30 Analysed (n): 30 Age (mean ± SD, median (IQR), median (range)): 43.9 ± 10.4 Weight (mean ± SD, median (IQR), median (range)): 57.9 ± 8.0 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 23/7/0/0 Gender (female in %): 77 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (N₂O/isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 75.5 Use of perioperative opioids (if yes, which?): NA Type of surgery: laparoscopic cholecystectomy Placebo Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 30 Received treatment (n): 30 Analysed (n): 30 Age (mean ± SD, median (IQR), median (range)): 39.6 ± 8.6 Weight (mean ± SD, median (IQR), median (range)): 60.3 ± 8.6 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 24/6/0/0 Gender (female in %): 63 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (N₂O/isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 79.4 Use of perioperative opioids (if yes, which?): NA Type of surgery: laparoscopic cholecystectomy Included criteria: USG diagnosed cholelithiasis scheduled for laparoscopic cholecystectomy under general anaesthesia, both sexes, ASA I and II Excluded criteria: patients with 18 or above 60 years of age; unable to cooperate or epileptic; impaired kidney or liver function; history of hypersensitivity to any drug; history of peptic ulcer disease; taking psychotropic drugs, calcium channel blockers, or antidepressants; for whom laparoscopic cholecystectomy was converted into open cholecystectomy Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia): no; (history of PONV/motion sickness, non‐smoker, perioperative opioids): unclear
Interventions	Intervention characteristics Ondansetron Dose: 4 mg Time point of administration: 10 to 15 minutes before surgery Route of administration: IV Rescue antiemetics (if yes, which?): granisetron 1 mg IV Dexamethasone Dose: 8 mg Time point of administration: 10 to 15 minutes before surgery Route of administration: IV Rescue antiemetics (if yes, which?): granisetron 1 mg IV Placebo Dose: 2 mL saline Time point of administration: 10 to 15 minutes before surgery Route of administration: IV Rescue antiemetics (if yes, which?): granisetron 1 mg IV
Outcomes	PONV (0 to 24 hours) Outcome type: dichotomous outcome
Identification	Sponsorship source: NA Country: India Setting: inpatient, single‐centre Author's name: Semira Institution: SKIMS Medical College, Bemina Kashmir Email: NA Address: Department of Pharmacology, SKIMS medical college, Bemina Kashmir, India 190001 Duration of study: NA Language: English Study's primary outcome: NA Trial registry number: NA
Notes	Three out of 4 groups relevant (gabapentin)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "the table of random numbers..."
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 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): no; (history of PONV/motion sickness, non‐smoker, perioperative opioids): unclear