Choo 2019.

Study characteristics
Methods	RCT Country: Malaysia
Participants	Adult patients (age ≥ 18 years) presenting to the ED with traumatic injuries of the extremities requiring tramadol (50 mg, up to 2 doses) for pain relief Baseline demographic data: mean age of 39 years, 24.1% female Study period: 6 months (Exact dates not reported)
Interventions	Intervention: 96 patients received metoclopramide 10 mg IV Control: 95 patients received 0.9% normal saline
Outcomes	Primary outcome: mean change in nausea severity using a 100 mm visual analogue scale at 60 min Secondary outcomes Number of vomiting episodes Need for rescue antiemetic therapy Adverse events
Notes	No funding support or author COIs
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A computerized random number generator was used.
Allocation concealment (selection bias)	Low risk	The allocation list was kept by a separate pharmacist.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The intervention and control medications were identical.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Treatment allocations were blinded until after study completion.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No participants were lost to follow‐up.
Selective reporting (reporting bias)	Low risk	All data were reported.
Other bias	Low risk	None