Title Efficacy of sodium zirconium cyclosilicate versus lactulose in the treatment of acute hyperkalemia
Authors Debika Kundu, PharmD; Alexa M. Campbell, PharmD; Kerri M. Smith, PharmD, BCPS; Jennifer A. Szwak, PharmD, BCPS, FCCP; Michael Snitzer, PharmD; Jose Manuel Monroy-Trujillo, MD; Dannielle R. Brown, PharmD, BCPS
Learning Objective Compare the efficacy and safety of sodium zirconium cyclosilicate (SZC) and lactulose for treatment of acute hyperkalemia.
Background/Objective Quantify and compare the efficacy of sodium zirconium cyclosilicate (SZC) and lactulose for potassium (K) reduction in acute hyperkalemia (K ≥ 5.5 mmol/L) and evaluate safety by assessing the incidence of hypokalemia
Methods This single-center, retrospective study included adults treated for acute hyperkalemia who were admitted to internal medicine services or treated in the emergency department between March 2020 and June 2024. Patients were included if they had serum potassium ≥ 5.5 mmol/L and received SZC or lactulose for treatment of hyperkalemia. Patients were excluded if they received intravenous insulin or hemodialysis within 24 hours of the index elevated potassium. Concomitant medications affecting potassium given within 24 hours of index elevated potassium were documented. Potassium was assessed at 6, 12, and 24 hours following the index potassium value. The primary endpoint was change in potassium at 12 hours. Secondary endpoints included change in potassium at 6 and 24 hours, the proportion achieving potassium < 5.5 mmol/L at 6, 12, and 24 hours, incidence of hypokalemia (K < 3.5 mmol/L), and quantification of study medication utilization.
Results A total of 341 hyperkalemia episodes involving 317 unique patients were included. Median age was 61.5 years, 42.5% were female and 20.8% had chronic kidney disease. SZC and lactulose were used in 65.7% and 34.3% of the incidences with median total doses over 24 hours of 10 g and 30 g, respectively. At 12 hours, K reduction was similar (-0.6 vs -0.55 mmol/L, p=0.208) with similar rates achieving K < 5.5 mmol/L (60.3% vs 61.9%, p=0.857). Similar reduction (-0.6 vs -0.35 mmol/L, p=0.0505) and goal attainment (54.64% vs 58.00%, p=0.697) were also observed at 6 hours. However, at 24 hours, SZC showed greater reduction (-0.7 vs -0.4 mmol/L, p=0.0002) and higher goal attainment (74.4% vs 63.8%, p=0.041). Hypokalemia occurred once in the SZC group.
Conclusion(s) At 24 hours, SZC demonstrated significantly greater potassium reduction and patients were more likely to achieve a target potassium level < 5.5 mmol/L compared to lactulose. However, SZC demonstrated similar efficacy compared to lactulose for the treatment of hyperkalemia at 6 and 12 hours, with no significant differences in potassium reduction or proportion of patients achieving K < 5.5 mmol/L. Both treatments were generally safe, with only one case of hypokalemia identified.
Self-Assessment Question: At 24 hours, which treatment was more effective in achieving potassium < 5.5 mmol/L in patients with acute hyperkalemia? Lactulose SZC [correct answer] Both were equally effective Neither achieved target potassium
