The presence of hyperkalemia is common in patients suffering from chronic heart failure due to concomitant chronic kidney disease. To treat hyperkalemia, sodium zirconium cyclosilicate (SZC), a recently designed selective potassium binder, has been clinically available. SZC could be a potential treatment option for hyperkalemia, especially in patients with heart failure who are frequently prescribed potassium-sparing drugs. However, the best initial SZC dose in terms of a loading dose (30 g per day for the first two days) versus a maintenance dose (5 g per day) is still uncertain.
Patients with chronic heart failure and hyperkalemia who had 2-day SZC therapy were included in the study retrospectively between July 2020 and November 2020. The two strategies (maintenance versus loading) were evaluated in terms of SZC treatment safety and efficacy. In addition, serum potassium levels were tested at the start of the study (day 0) and again two days later (day 2).
Sixteen patients with a median age of 76 were enrolled in the trial and were given SZC treatment for two days (4 maintenance dose group and 12 loading dose group). Of the total study population, 11 (69%) of them were male. Two days of maintenance dosage therapy reduced serum potassium by 0.7 mEqL/L, and two days of loading dose therapy reduced serum potassium by 1.3 mEqL/L. After two days of SZC medication, 25% of patients had hypokalemia, defined as serum potassium less than 4.0 mEq/L. There were no cases of peripheral edema, tiredness, nasopharyngitis, or upper respiratory tract infection during the 2-day SZC treatment.
In individuals with heart failure and hyperkalemia, SZC reduces serum potassium by around 1.0 mEq/L almost immediately. To avoid iatrogenic hypokalemia, attention should be exercised when using SZC at a loading dose, especially in people with mild hyperkalemia.