Background: The use of sodium polystyrene sulfonate (SPS) for the treatment of hyperkalemia lacks sufficient efficacy data in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD); however, use remains widespread. Recent evidence suggests that this population may be at risk for serious gastrointestinal adverse effects with SPS. Methods. We conducted a single-center retrospective cohort study. Adult patients with CKD Stages 4, 5, or ESRD maintained on renal replacement therapy with serum potassium >5 mEq/L and receipt of SPS were screened for inclusion. Our primary outcome was decrease in potassium within 24 h post-30 g oral SPS suspended in 33% sorbitol. Secondary outcomes included decrease in potassium within 24 h from 15 or 30 g SPS doses and gastrointestinal adverse events.
Results: Of 596 records, 114 were included for analysis. At the first serum potassium level within 24 h post-30 g oral SPS the median potassium decrease was 0.8 mEq/L [interquartile range (IQR) 0.4-1.1; P < 0.001]. At the first potassium level within 24 h post-15 or 30 g SPS, the median potassium decrease was 0.7 mEq/L (IQR 0.4-1.0; P < 0.001]. Post-SPS potassium levels occurred 14-16 h post-SPS. Gastrointestinal side effects occurred within 30 days of SPS in 5% of patients, although only two cases were classified as possibly associated.
Conclusions: The use of single-dose SPS monotherapy resulted in a significant decrease in serum potassium levels within 24 h in patients with CKD Stage 4, 5, or ESRD. However, it remains unclear if SPS is associated with an increased risk of gastrointestinal injury in this population.
Keywords: chronic kidney disease; end-stage renal disease; hyperkalemia; sodium polystyrene sulfonate.