Management of hyperkalemia in chronic heart failure using sodium zirconium cyclosilicate

Background: Sodium zirconium cyclosilicate (SZC), a newly-developed selective potassium binder, has been clinically available to treat hyperkalemia. SZC might be a promising option to manage hyperkalemia, particularly in patients with heart failure, who often require potassium-sparing medications. However, the optimal initial dose of SZC therapy at a loading dose (30 g per day for the initial 2 days) versus a maintenance dose (5 g per day) remains unknown. Methods: Consecutive patients with heart failure and hyperkalemia who received 2-day SZC therapy were retrospectively included. Safety and efficacy of SZC therapy were compared between the two strategies (maintenance versus loading). Results: We had 16 patients (76 years old, 11 men) who received 2-day SZC therapy (4 maintenance dose group and 12 loading dose group). Serum potassium decreased 0.7 mEqL/L by 2-day maintenance dose therapy and 1.3 mEq/L by 2-day loading dose therapy. Following 2-day SZC therapy, 25% of patients had hypokalemia, which was defined as serum potassium <4.0 mEq/L. Baseline lower serum potassium level was associated with the post-SZC hypokalemia. Conclusions: SZC immediately decreases approximately 1.0 mEq/L of serum potassium in patients with heart failure and hyperkalemia. However, caution should be exercised when utilizing SZC at a loading dose specifically in those with mild hyperkalemia to prevent iatrogenic hypokalemia.