Salbutamol for analgesia in renal colic: a prospective, randomised, placebo-controlled phase II trial

The pain of renal colic, mediated in part by ureteral spasm and inflammation, is often severe and difficult to control. Salbutamol has been shown to cause ureteral relaxation, but its effects on the pain of renal colic have never been studied. The objective of this trial was to investigate whether the use of intravenous salbutamol in addition to standard analgesia was associated with greater pain reduction compared with standard analgesia alone in patients presenting to emergency departments (EDs) with renal colic.

This single-centre, double-blind, phase II, randomised, placebo-controlled trial recruited adult (≥18 years) ED patients with clinically suspected renal colic. Participants were randomised in a 1:1 ratio to receive either 250 µg of intravenous salbutamol or a placebo (0.9% sodium chloride). The primary outcome was the difference in the change in pain scores (measured on a 100 mm Visual Analogue Scale) from baseline to 30 min following trial treatment administration in participants with subsequently confirmed renal colic. A modified intention-to-treat analysis was undertaken for the primary population of participants with confirmed renal colic.

Consent was obtained from 151 patients; 108 participants with confirmed renal colic were included in the primary outcome analysis. There was no statistical difference between groups in median change in pain score at 30 min (salbutamol group -18 mm (IQR -25 to -3), placebo group -13 mm (IQR -33 to -1), difference 5 mm (95% CI -16 to 6, p=0.575)). No significant differences were found in the secondary outcomes related to pain, patient satisfaction or opiate requirement.More adverse events (AEs) were observed in the salbutamol group (65) compared with placebo (42, p=0.02); no unexpected AEs were identified.

This trial has not identified a clinically or statistically significant benefit from the addition of intravenous salbutamol to standard care for patients presenting to an ED with pain caused by renal colic.

The trial was registered with the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT), reference 2018-004305-11. It was also registered with the ISRCTN Registry, reference 14552440.