Evaluation of the tolerability and efficacy of sodium polystyrene sulfonate for long-term management of hyperkalemia in patients with chronic kidney disease

Abstract

Sodium polystyrene sulfonate (SPS) is a cation-exchanging resin that has been widely used for several decades as first-line therapy of mild chronic hyperkalemia in patients with chronic kidney disease (CKD). However, evidence to prove the long-term tolerability and efficacy of SPS for the treatment of this condition is still missing. In this retrospective, observational study, we enrolled 26 outpatients with stages 3-4 CKD who received oral therapy with low-dose SPS for mild chronic hyperkalemia in the Outpatient Nephrology clinic of our Department during 2010-2016. We obtained medical records on side effects potentially attributable to SPS use, and we analyzed the changes in serum electrolytes before and after the initiation of SPS therapy. Serum potassium levels fell from 5.9±0.4 to 4.8±0.5mmol/l (P<0.001) over a median follow-up of 15.4months (range 3-27months). SPS use was associated with a slight, but significant elevation in serum sodium levels (139.5±2.9 vs 141.2±2.4, P=0.006), whereas serum calcium and phosphate remained unchanged before and after the initiation of SPS. We recorded ten episodes of recurrent serum potassium elevation ≥5.5mmol/l, none of which required hospitalization or acute dialysis. No episode of colonic necrosis or any other serious drug-related adverse event was observed. SPS therapy was well-tolerated, since only 1 out of 26 patients discontinued SPS at 3months due to gastrointestinal intolerance. This study suggests that low-dose SPS is well-tolerated and can effectively normalize elevated serum potassium over several weeks in CKD outpatients with mild chronic hyperkalemia.