Single Dose of Sodium Zirconium Cyclosilicate Versus Sodium Polystyrene Sulfonate in Hospitalized Patients With Hyperkalemia.

Background: Sodium zirconium cyclosilicate (SZC) is an inorganic zirconium silicate compound that selectively exchanges potassium for hydrogen and sodium. "Once" doses of SZC (with option to redose) in patients with hyperkalemia in hospitalized settings have not been evaluated. We hypothesized that a once dose of SZC would be non-inferior to sodium polystyrene sulfonate (SPS) in reducing serum potassium.

Objective: The objective of our study is to evaluate the effect of a "once" dose of SZC when compared with SPS in reducing serum potassium levels.

Methods: This was a retrospective analysis of patients who received either a "once" dose of SZC or single or repeated doses of SPS for hyperkalemia. The primary endpoint was mean absolute reduction in the first serum potassium value at least 4 hours after administration. The secondary efficacy endpoints were the rate of additional potassium-lowering therapies and the rate of normokalemia within 48 hours. Safety endpoints were the incidence of electrolyte abnormalities, hypoglycemia, hypertension, hypotension, and colonic necrosis.

Results: A total of 260 patients were included in the analysis. The mean initial serum potassium was similar between groups (5.6 ± 0.4). The absolute serum potassium reduction was -0.88 ± 0.64 mEq/L and -0.75 ± 0.65 mEq/L with SZC and SPS, respectively. The "once" regimen of SZC demonstrated non-inferiority compared with SPS ( < 0.0001). The proportion of patients achieving normokalemia within 48 hours and the proportion of patients receiving additional potassium-lowering therapies did not differ between groups.

Conclusion And Relevance: The "once" dose regimen (with redose option) of SZC was non-inferior to the "once" or repeated dosing regimen of SPS with regard to absolute potassium reduction. There were no significant differences in the rate of additional potassium-lowering therapies and the rate of normokalemia at 48 hours. The incidence of hypertension was less common among patients who received SZC.