Abstract
BACKGROUND AND STUDY AIMS: Topical peppermint oil prevents intestinal spasm, but can cause rebound spasm. Lidocaine hydrochloride, a local anesthetic, may work as an antispasmodic by blocking Na + channels. The aim of this study was to investigate the effect of topical lidocaine on the inhibition of colonic spasm during colonoscopy, compared with peppermint oil. PATIENTS AND METHODS: A randomized, controlled double-blind trial was conducted in an academic endoscopy unit. Patients requiring endoscopic resection were randomly allocated to colonoscopy with topical administration of lidocaine (n = 30) or peppermint oil (n = 30). Similar vials containing different solutions were randomly numbered. Allocation was made based on the vial number. The solution used and the vial number were not revealed during the study. Two endoscopists performed all procedures using midazolam, without anticholinergic agents. When a pre-selected lesion was identified, the solution in the assigned vial was dispersed and the bowel observed for 5 minutes. The primary endpoint was the duration of spasm inhibition, and a secondary endpoint was the occurrence of rebound spasm stronger than before dispersion. RESULTS: There were no significant differences in patient demographics. Spasm was inhibited in almost all patients in both groups, with a similar median duration (lidocaine 227 sec vs. peppermint 212.5 sec, P = 0.508). In contrast, rebound spasm occurred less frequently in the lidocaine group (lidocaine 7 % vs. peppermint 47 %, P = 0.001). There were no adverse events or symptoms associated with administration of the solutions. CONCLUSIONS: The inhibitory effect of lidocaine is not superior to peppermint oil. However, lidocaine significantly decreases the frequency of rebound spasms.