Comparison of the Effects of Diltiazem Gel with Lidocaine Gel on Reducing Pain and Discomfort in Patients Undergoing Rectosigmoidoscopy: A Randomized Double-blinded Clinical Trial

Background: Flexible rectosigmoidoscopy is an easy and accessible exam to diagnose distal colon diseases, although many patients refuse to undergo it due to pain and discomfort during the procedure. Studies show that the application of local lidocaine, as an analgesic has no effect on pain relief in patients undergoing rectosigmoidoscopy. The current study aims at comparing the effects of diltiazem gel, an antispasmoic drug with local pain-reducing effects, with lidocaine gel in patients undergoing flexible rectosigmoidoscopy. Materials and Methods: The current double-blinded, randomized, clinical trial was performed to compare the effect of two topical drugs, lidocaine and diltiazem, on pain relief in patients undergoing rectosigmoidoscopy. A total of 80 patients who were potential candidates for rectosigmoidoscopy were enrolled in the study after obtaining the informed consent and then randomly assigned to one of the lidocaine gel (2 mL) or diltiazem gel (2 mL) group, 10 minutes prior to rectosigmoidoscopy. The level of pain in the patients during the procedure was measured using the visual analogue scale (VAS) and the results were recorded. The data were analyzed using paired samples ttest and independent t-test as well as analysis of covariance (ANOVA) with SPSS version 18. P-value <0.05 was considered the level of significance. Results: Of 80 patients, 35 (43.75%) were male and 45 (56.25%) female. The mean age and body mass index (BMI) of the patients were 51.45 ± 15.21 years and 25.95 ± 7.47 kg/m2, respectively, and there was no significant difference between the groups. The most frequent indications for rectosigmoidoscopy were abdominal pain (46.3%) and rectorrhagia (31.3%). The mean VAS score for pain reported by the patients in the lidocaine and diltiazem groups was 3.97 ± 2.89 and 2.60 ± 2.36, respectively. The VAS score for pain in the diltiazem group was significantly lower than lidocaine group (P = 0.023). Conclusion: The application of local diltiazem gel around the anus, in spite of no side effects, can effectively reduce the pain and discomfort in patients during rectosigmoidoscopy. Iranian Registry of Clinical Trials (Reg. No 31055).