Caravati 1989.

Methods	Study design: cross‐over RCT Study duration: NS Duration of follow‐up: 15 min/phase
Participants	Country: USA Setting: multicentre All patients between 18 and 75 y presenting to the ED with the signs and symptoms of acute renal colic Number: 35 randomised, 30 analysed Mean age ± SD: 32 ± 12 years Sex (M/F): 27/3 Exclusion criteria: nifedipine hypersensitivity; unstable vital signs; severe aortic stenosis; pregnancy; myocardial infarction
Interventions	Treatment group Nifedipine:10 mg to 20 mg (oral) Control group Placebo
Outcomes	VAS‐10 Vital signs Need for rescue medication
Notes	Source of funding: Pfizer Pharmaceuticals
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random number table
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) Medication used	Low risk	Patients and clinicians blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	Withdrawn and not crossed over patients did not enter the analysis
Selective reporting (reporting bias)	Low risk	All pre‐specified primary and secondary outcomes are reported
Other bias	Unclear risk	Industry sponsorship could be a source of bias