Choi 2016.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, combination prophylaxis
Participants	Baseline characteristics Aprepitant + palonosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 44 Received treatment (n): 44 Analysed (n): 44 Age (mean ± SD, median (IQR), median (range)): 48.9 ± 10.6 Weight (mean ± SD, median (IQR), median (range)): 58.9 ± 8.9 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA Gender (female in %): 100 Non‐smoker (%): 100 History of PONV/motion sickness (%): 30 Type of general anaesthesia: balanced anaesthesia (sevoflurane, remifentanil) Duration of anaesthesia or surgery (in min; as mean or median): 55.7 Use of perioperative opioids (if yes, which?): intraoperative remifentanil, 103.41 µg fentanyl Type of surgery: laparoscopic cholecystectomy Aprepitant + ramosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 44 Received treatment (n): 44 Analysed (n): 44 Age (mean ± SD, median (IQR), median (range)): 48.8 ± 10.2 Weight (mean ± SD, median (IQR), median (range)): 60.9 ± 8.6 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA Gender (female in %): 100 Non‐smoker (%): 100 History of PONV/motion sickness (%): 25 Type of general anaesthesia: balanced anaesthesia (sevoflurane, remifentanil) Duration of anaesthesia or surgery (in min; as mean or median): 63.5 Use of perioperative opioids (if yes, which?): intraoperative remifentanil, 102.27 µg fentanyl Type of surgery: laparoscopic cholecystectomy Included criteria: ASA physical status of I or II, non‐smoking, female, 18 to 65 years of age, scheduled for laparoscopic cholecystectomy Excluded criteria: gastrointestinal disorder; allergy to any study medication; had received any sedative, opioid, steroid, or antiemetic within 24 hours before surgery Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness): no; (perioperative opioids): unclear
Interventions	Intervention characteristics Aprepitant + palonosetron Dose: aprepitant 80 mg, palonosetron 0.075 mg Time point of administration: aprepitant 2 hours before surgery, palonosetron 10 minutes after induction of anaesthesia Route of administration: aprepitant PO, palonosetron IV Rescue antiemetics (if yes, which?): 11.4% (metoclopramide 10 mg) Aprepitant + ramosetron Dose: aprepitant 80 mg, ramosetron 0.3 mg Time point of administration: aprepitant 2 hours before surgery, ramosetron 10 minutes after induction of anaesthesia Route of administration: aprepitant PO, ramosetron IV Rescue antiemetics (if yes, which?): 40.9% (metoclopramide 10 mg)
Outcomes	Vomiting (0 to 24 hours) Outcome type: dichotomous outcome Vomiting (0 to 2 hours) Outcome type: dichotomous outcome Vomiting (2 to 24 hours) Outcome type: dichotomous outcome Nausea (0 to 24 hours) Outcome type: dichotomous outcome Headache (overall, exact time point unknown) Outcome type: dichotomous outcome Sedation/drowsiness (overall, exact time point unknown) Outcome type: dichotomous outcome Adverse events (general notes in the publication, overall, exact time point unknown) Outcome type: general notes on side effects
Identification	Sponsorship source: NA Country: Korea Setting: inpatient, single‐centre Author's name: Younghoon Jeon Institution: Department of Anesthesiology and Pain Medicine, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea Email: jeon68@knu.ac.kr Address: Department of Anesthesiology and Pain Medicine, School of Dentistry, Kyungpook National University, 188‐1 Samdeok‐Dong 2 Ga, Jung‐gu, Daegue 700‐421 Republic of Korea Language: English Duration of study: NA Trial registry number: NCT02597907 Study's primary outcome: incidence of PONV
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "patients were randomly allocated to one of 2 groups (n = 44 in each) using a computer‐generated random number table"
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 on blinding of participants and personnel
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "all data were assessed by another anesthesiologist blinded to the group assignments during the first 24 hours after surgery in 2 time periods (0 to 2 and 2 to 24 h after anesthesia),,,"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "a total of 88 patients completed the study"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: NCT02597907 (retrospective registration)
Other bias	Unclear risk	Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness): no; (perioperative opioids): unclear