Ondansetron and the Risk of Sudden Cardiac Death among Individuals Receiving Maintenance Hemodialysis

Background Individuals receiving hemodialysis have a high incidence of sudden cardiac death and are susceptible to QT interval-prolonging medication-related cardiac complications. Ondansetron, an antiemetic with known QT-prolonging potential, is associated with fatal arrhythmias in the general population when administered intravenously. The cardiac safety of ondansetron in the hemodialysis population is unknown. Methods We conducted a new-user, active-comparator, cohort study using United States Renal Data System data (2012-2019) to examine the association between the initiation of oral ondansetron versus antiemetics with lesser QT-prolonging potential (promethazine, metoclopramide, or prochlorperazine) and the 10-day risk of sudden cardiac death among individuals receiving hemodialysis. We used inverse probability of treatment-weighted survival models to estimate adjusted hazard ratios, risk differences, and 95% confidence intervals (CIs). We used an intention-to-treat approach in which non-sudden cardiac death was considered a competing event. We examined additional cardiac outcomes in secondary analyses. Results Of 119,254 study patients, 64,978 (55%) initiated ondansetron and 54,276 (45%) initiated a comparator antiemetic. Initiation of ondansetron versus a comparator antiemetic was associated with higher relative and absolute 10-day risks of sudden cardiac death (adjusted hazard ratio, 1.44 [95% CI, 1.08 to 1.93]; adjusted risk difference, 0.06% [95% CI, 0.01% to 0.11%]). The number needed to harm was 1688. Analyses of additional cardiac outcomes yielded similar findings. Conclusions Compared with initiation of antiemetics with lesser QT-prolonging potential, initiation of ondansetron was associated with higher short-term cardiac risks among people receiving hemodialysis.