Abstract Purpose To investigate whether placebo is non-inferior to continuous infusion of butylscopolamine in patients with renal colic. Methods We conducted a placebo-controlled, multicenter, double-blind randomized clinical trial (RCT) including 128 patients with renal colic (confirmed by ultrasound or CT-scan). Patients were randomized to receive either continuous IV butylscopolamine 100 mg/24 h or placebo (saline). Primary outcome is the amount of opioid escape medication used, measured in doses administered. Secondary outcomes are pain measured on a Numeric Rating Scale (NRS), side effects, and time of drug administration. Non-inferiority was assessed using linear regression with robust standard errors, with non-inferiority limit set at 0.5 units of escape medication. Results Median number of doses of escape medication was one in both groups. The number of extra doses in the placebo group compared with the butylscopolamine group was 0.05, with a 95% robust confidence interval (CI) of 0.38–0.47. Upper limit of the CI remained below the non-inferiority limit of 0.5 (p = 0.04). No differences in secondary endpoints were seen between the groups. Conclusion Placebo is non-inferior to continuous IV butylscopolamine for pain relief in patients with renal colic. Based on this study and previous evidence, there is no role for continuous butylscopolamine IV in the treatment of renal colic. Trial NL7819