Cho 2017.

Methods	Study design: double‐blind placebo‐controlled RCT. Study duration: unknown. Follow‐up/Treatment duration: 90 days.
Participants	Country: South Korea. Setting: multi‐centre. Patients > 20 years of age with a single ureteral stone. The maximal diameter of the stones was 3 ± 10 mm. Number: treatment group: 64; placebo group: 60. Mean age ± SD, years: treatment group: 48.1 ± 14.2; placebo group: 42.33 ± 12.58. Sex, M/F: treatment group: 49/15; placebo group: 41/19. Exclusion criteria: presence of multiple ureter stones; renal or hepatic dysfunction; febrile urinary tract infection; breastfeeding or pregnant women; solitary kidney; hypersensitivity to naftopidil; current use of alpha‐blockers, calcium channel blockers, or corticosteroid within 4 weeks; moderate to severe cardiovascular or cerebrovascular disease; significant active medical illness or genetic disorders.
Interventions	Treatment group Naftopidil 75 mg once daily. Placebo group All participants received aceclofenac 100 mg or combination treatment with tramadol 37.5 mg and acetaminophen 325 mg.
Outcomes	Primary outcome measures Stone‐free rate. Secondary outcome measures Stone‐free rate at 28th day of study. Quantity of analgesics used. Rate of active treatment.
Funding sources	None.
Declarations of interest	None.
Notes	Participants were followed up at days 14 (visit 1), 28 (visit 2), 60 (visit 3), and 90 (visit 4) after initiation of medication.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was carried out by the Medical Research Collaboration Center of Seoul National University Bundang Hospital using random permuted blocks of different sizes. The size of the next block was randomly chosen from the available block sizes." Comment: This method of random sequence generation was considered to have low risk of bias.
Allocation concealment (selection bias)	Low risk	Quote: "The size of the next block was randomly chosen from the available block sizes. Randomization was stratified by each recruiting study site." Comment: This method of allocation concealment was considered to have low risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "One person packed the 14‐day supply of tablets for each patient. All study staff at all hospitals were blinded to treatment allocation and remained blind until the end of the trial." Comment: double‐blind; therefore low risk of bias.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No quotes available. No blinding of outcome assessments described. Comment: Owing to insufficient information, risk of detection bias was considered to be unclear.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No quotes available. Figure 1 shows a detailed flow diagram of participant follow‐up, including information regarding loss to follow‐up, exclusion due to adverse events, or need for intervention. Comment: Detailed information on participant follow‐up was available; risk of attrition bias was considered to be low.
Selective reporting (reporting bias)	Low risk	No quotes available. Expected outcomes were reported according to objectives. Comment: Information on primary and secondary outcomes was presented in detail in the protocol at www.clinicaltrials.gov. Risk of reporting bias was therefore considered to be low.
Other bias	Low risk	No quotes available. Study appears to be free of other sources of bias. Comment: No other sources of bias could be found; therefore risk of other bias was considered to be low.