SZC Shows Superior Efficacy and Safety Over SPS in Treating Hyperkalemia in hemodialysis patients: Study

Data from a new clinical trial revealed that compared to sodium polystyrene sulfonate (SPS) treatment, Sodium zirconium cyclosilicate (SZC) provided faster and more effective resolution of hyperkalemia, with a potentially improved safety profile and better palatability in hemodialysis patients. The findings were published in the BMC Nephrology journal.

Hyperkalemia is a frequent and potentially fatal complication in patients receiving maintenance dialysis. Despite the widespread use of potassium binders like SPS, comparative data on newer therapies has remained limited, until now.

This multicenter, double-blinded, randomized clinical trial enrolled 120 HD patients with predialysis serum potassium levels exceeding 5 mmol/L. Participants were assigned to receive either SZC (5 grams, thrice weekly on non-dialysis days, totaling 15 grams per week) or SPS (15 grams, thrice weekly, 45 grams per week) over an 8-week period. The primary outcome was the change in serum potassium levels during the treatment phase.

The results found both groups to experience a statistically significant reduction in serum potassium levels beginning in the first week and continuing throughout the study period (p < 0.001 for both groups). However, SZC outpaced SPS in bringing patients into the normal potassium range (normokalemia), achieving this milestone by the second week, whereas SPS-treated patients did not reach normokalemia until the sixth week (p < 0.001).

The rescue therapy for hyperkalemia was used when potassium levels pose an acute risk, was required less often in the SZC group (3.3%) when compared to the SPS group (6.6%), although this difference was not statistically significant (p = 0.678).

Gastrointestinal side effects, a known concern with potassium binders, were reported by 5% of patients in the SZC group and 11.6% in the SPS group, a non-significant difference. However, palatability emerged as a clear differentiator. SZC was rated as significantly more palatable than SPS (p < 0.001), an advantage that could enhance patient compliance.

While both agents demonstrated safety and effectiveness in lowering potassium levels, the study's data suggest SZC may offer a faster, better-tolerated, and more patient-friendly alternative to the traditional SPS approach.

The study data compared weekly average serum potassium levels between the two groups over the 8-week trial. SZC-treated patients saw a sharper and earlier decline in potassium, with normalization occurring by week 2. In contrast, SPS showed a more gradual decrease, achieving normokalemia only by week 6.

Additionally, gastrointestinal side effects and the need for rescue therapy were numerically lower in the SZC group. Patient-reported palatability scores strongly favored SZC, reinforcing its potential advantages in clinical practice.

Source:

Elsayed, M. M., Abdelrahman, M. A., Sorour, A. M., Rizk, I. G., & Hassab, M. A. A. (2025). Sodium zirconium cyclosilicate versus sodium polystyrene sulfonate for treatment of hyperkalemia in hemodialysis patients: a randomized clinical trial. BMC Nephrology, 26(1). https://doi.org/10.1186/s12882-025-04129-9