Constipation as a Drug-Related Adverse Effect in Patients with Hyperkalemia: Sodium Zirconium Cyclosilicate versus Conventional Potassium Binders

Abstract

(1) Background: Constipation is one of the most serious adverse effects of potassium-lowering agents and decreases patients' quality of life. Sodium zirconium cyclosilicate (SZC) is a recently innovated potassium binder intended for patients with hyperkalemia. The impact of SZC on the worsening of constipation, as compared with conventional potassium binders, remains unknown. (2) Methods: Patients with hyperkalemia who continued SZC for over 3 months between July 2020 and May 2022 were included in this retrospective study. Patients who received other conventional potassium binders during the same period were included as a control group. Trends in the doses of anti-constipation agents during the 3-month therapeutic period were compared between the two groups as a surrogate for worsening constipation. (3) Results: A total of 50 patients (median age 74 years, 31 male) were included, consisting of 22 patients with SZC and 28 patients with other conventional potassium binders. All patients had hyperkalemia and chronic kidney disease at baseline. During the 3-month therapeutic period, serum potassium levels decreased significantly in both groups (p < 0.05 for both). The number of anti-constipation remained unchanged in the SZC group but tended to increase in the control group (p = 0.56 and p = 0.090, respectively). The total dose change in all anti-constipations was significantly lower in the SZC group than in the control group (p = 0.037). (4) Conclusions: Conventional potassium binders have a tendency to worsen constipation, whereas SZC may have the potential to improve hyperkalemia without worsening constipation. SZC may be recommended, particularly in elderly patients with ongoing or high-risk constipation.

Keywords: heart failure; potassium; renal failure.

Figure 1

Trends in the number of anti-constipation agents during the 3-month therapeutic period. The number of anti-constipation agents remained unchanged in the SZC group whereas those in the control group tended to increase during 3-month therapeutic period. The number of each anti-constipation agent was counted regardless of its dose. The trends were assessed using the Wilcoxon signed-rank test.

Figure 2

Distribution of total dose change during the 3-month therapeutic period in the two groups. Most patients in the SZC group had a total dose change of zero, whereas some patients had 1–3 total dose changes in the control group. The total dose change was significantly lower in the SZC group than in the control group. For example, when a patient had an increase in dose of magnesium oxide (dose change was defined as “+1”) and a decrease in sennoside (dose change was defined as “−1”), a total dose change was calculated as zero. * p < 0.05 by Wilcoxon signed-rank test.