Dose-Dependent Efficacy of Nefopam for Preventing Catheter-Related Bladder Discomfort in Patients Undergoing Transurethral Ureteroscopic Lithotripsy: A Retrospective Case-Control Observational Study.

Background/Objectives: Catheter-related bladder discomfort (CRBD) is a common complication that patients with Foley catheters may experience following surgery. Previous studies have suggested that nefopam can reduce the incidence and severity of CRBD; however, dose-dependent effects (20 mg vs. 40 mg) have not been directly compared. Therefore, this study aimed to evaluate the dose-dependent effects of nefopam on CRBD, determine its effective dose, and assess the incidence of associated side effects. Methods: Electronic medical records of patients aged 18-70 years with American Society of Anesthesiologists physical status I-III who underwent elective transurethral ureteroscopic lithotripsy under general anesthesia from August 2016 to December 2022 were reviewed. Patients were categorized into three groups: premedication with intravenous nefopam 20 mg (group N20), premedication with nefopam 40 mg (group N40), or no premedication (control, group C). Results: The incidence rates of CRBD were 85.7% in group C, 81.3% in group N20, and 51.4% in group N40, showing a significant difference among the groups (p = 0.003, Pearson's chi-squared test). Postoperative NRS was significantly different among the groups (p < 0.001, one-way ANOVA). In post hoc analysis, both group N20 and group N40 showed significantly lower scores compared to group C (p = 0.002, p = 0.001 respectively). The severity of CRBD also decreased in a dose-dependent manner, which was considered significant. No significant differences were observed among the groups in terms of intraoperative hemodynamic stability or postoperative nausea and vomiting. Conclusions: The administration of nefopam 40 mg significantly reduced the incidence and severity of CRBD compared with no premedication.