Song 2017.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Ramosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 150 Received treatment (n): 150 Analysed (n): 150 Age (mean ± SD, median (IQR), median (range)): NA (reported for different genotypes, no difference between groups) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): NA (reported for different genotypes, no difference between groups) ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): NA (reported for different genotypes, no difference between groups) Non‐smoker (%): NA (reported for different genotypes, no difference between groups) History of PONV/motion sickness (%): NA (reported for different genotypes, no difference between groups) Type of general anaesthesia: balanced anaesthesia (sevoflurane, remifentanil) Duration of anaesthesia or surgery (in min; as mean or median): NA (reported for different genotypes, no difference between groups) Use of perioperative opioids (if yes, which?): remifentanil, fentanyl via PCA (reported for different genotypes, no difference between groups) Type of surgery: spinal surgery Palonosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 150 Received treatment (n): 150 Analysed (n): 146 Age (mean ± SD, median (IQR), median (range)): NA (reported for different genotypes, no difference between groups) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): NA (reported for different genotypes, no difference between groups) ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): NA (reported for different genotypes, no difference between groups) Non‐smoker (%): NA (reported for different genotypes, no difference between groups) History of PONV/motion sickness (%): NA (reported for different genotypes, no difference between groups) Type of general anaesthesia: balanced anaesthesia (sevoflurane, remifentanil) Duration of anaesthesia or surgery (in min; as mean or median): NA (reported for different genotypes, no difference between groups) Use of perioperative opioids (if yes, which?): remifentanil, fentanyl via PCA, (reported for different genotypes, no difference between groups) Type of surgery: spinal surgery Included criteria: 20 to 85 years of age, ASA I or II, undergoing spinal surgery (type of surgery included cervical laminoplasty, cervical anterior interbody fusion, lumbar laminectomy, posterior lumbar interbody fusion, and benign spinal cord tumour removal) Excluded criteria: administration of an antiemetic within 24 hours before surgery, regular administration of opioids or corticosteroids, history of psychiatric disorder, active drug or alcohol abuse, gastrointestinal motility disorder, severe hepatic or renal disease, uncontrolled diabetes, pregnancy, malignancy, body mass index > 35 kg/m², postoperative admission to an intensive care unit Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no
Interventions	Intervention characteristics Ramosetron Dose: 0.3 mg Time point of administration: 20 minutes before end of surgery and 24 hours after surgery Route of administration: IV Rescue antiemetics (if yes, which?): (19%) metoclopramide 10 mg Palonosetron Dose: 0.075 mg Time point of administration: 20 minutes before end of surgery and 24 hours after surgery Route of administration: IV Rescue antiemetics (if yes, which?): (26%) metoclopramide 10 mg
Outcomes	Vomiting (0 to 6 hours) Outcome type: dichotomous outcome Adverse events (general notes in the publication, 48 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: supported solely by departmental sources Country: Korea Setting: inpatient, single‐centre Author's name: Young Lan Kwak Institution: Department of Anesthesiology and Pain Medicine; and Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea Email: ylkwak@yuhs.ac Address: Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research, Institute Yonsei University College of Medicine, 50 Yonsei‐ro, Seodaemun‐gu, Seoul 120‐752, Republic of Korea Duration of study: NA Language: English Study's primary outcome: incidence of PONV during postoperative 48 hours for patients with ABCB1 TT and non‐TT genotype who received prophylactic ramosetron or palonosetron Trial registry number: NCT02480088
Notes	Repetitive dose of study drug after 24 hours
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "patients were assigned to either the ramosetron or the palonosetron group according to a computer‐generated randomization list"
Allocation concealment (selection bias)	Low risk	Quote: "sequentially numbered opaque envelopes containing the group assignment were opened on the day of operation by a nurse who was not involved in patients’ management, and the nurse prepared the study drugs as assigned" Judgement comment: SNOSE
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "...by a nurse who was not involved in patients’ management, and the nurse prepared the study drugs as assigned. The group assignment was blinded to both patients and investigators until the end of the study"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Judgement comment: quote: "the group assignment was blinded to both patients and investigators until the end of the study"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "four patients in the palonosetron group were excluded because they were transferred to the intensive care unit after surgery (Fig. 1)"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: NCT02480088 (retrospective registration)
Other bias	Low risk	Quote: "patient characteristics and operative data were comparable between the ramosetron and palonosetron groups, as well as between the non‐TT and TT for each group (Table 1)" Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no