Introduction. Hyperkalemia is a pathological condition characterized by muscular weakness, hypotension, shortness of breath, cardiac arrhythmias and, as a consequence, an increase in mortality. Its importance is especially substantial in patients on hemodialysis (HD) in interdialytic periods of time. Complications of hyperkalemia are more likely to occur after a two-day break, when fluid overload and potassium concentrations are highest.
Objective. To study the safety and efficacy of Kalimeyt in patients who are on renal replacement therapy of HD in interdialytic days with two regimens – 4 and 2 days per week.
Materials and methods. 33 stable patients without severe comorbidities with potassium levels of 5,5–7,0 mmol/l before HD after a long interdialysis interval were included in an open prospective cohort study on the safety and efficiency of calcium polystyrene sulfonate (Kalimeyt) administration in interdialysis days with two regimens – 4 and 2 days a week. 1 month was the phase of the drug washing between the different modes of taking the medicine. Acid-base state, blood electrolytes, ECG were determined weekly; general and biochemical blood tests – monthly.
Results. During the regimen of Kalimeyt intake 4 days a week (in interdialysis days), the average dose of the drug was 89±21 g /week, and the level of potassium decreased from 6,33±0,5 to 5,17±0,5 mmol/l (p<0,01) after a two-day break. Kalimeyt intake 2 days per week also showed the same effect. The average dose of Kalimeyt was 43,05±7,5 g/week and the level of potassium decreased from 6,2 0,5 to 5,22±0,5 mmol/l (p<0,01). The average level of potassium in one-day interdialysis interval did not differ in both modes (5,4±0,6 mmol/l vs 5,3±0,4 mmol/l). Assessment the dynamics of the QTc interval reliably showed its decline from 0,392±0,062 against 0,327±0,027 ms (р<0,01), which did not go beyond the permissible norm. However, in 7 patients of 27 (25,9%) at the stage of screening the QTc interval duration was above normal values. Serious adverse events in patients taking Kalimeyt were not recorded.
Conclusion. Good therapeutic effects of the cation exchange resin Kalimeyt in reducing the potassium level to the target values and a significant decrease in the QTc interval to normal values were demonstrated for the first time in patients on HD, as when taking the medicine every interdialytic day and only in a two-day interdialytic period. There was an equal efficacy of the medicine with a four- and two-day intake. When medicine was taken two days a week, drug load significantly decreased (by 2 times), which reduced the risk of side effects.

Keywords: cation exchange resin, hyperkalemia, hemodialysis