*Purpose: Hyperkalemia is a common problem experienced by kidney transplant recipients (KTR)s. New strategies to treat hyperkalemia are now available. KTRs often require medications that raise serum potassium (K). Sodium zirconium cyclosilicate (ZS-9) lowers serum K levels via exchanging sodium and hydrogen for potassium in the gastrointestinal tract. Its safety and efficacy in KTRs is unknown.

*Methods: This was a single-center retrospective analysis of KTRs with hyperkalemia (serum K >5.1mEq) treated with sodium zirconium cyclosilicate from 12/2019 – 10/2020. Treatment was determined by electronic medical record review of the medication administration record and/or documented use. Primary outcomes were need for renal replacement therapy and change in serum K at ~ 48 hours (mmol/L). Secondary outcomes included use of potassium raising medications, mean change in tacrolimus level (ng/dL), significant hypokalemia (serum K <3.0mmol/L), major gastrointestinal adverse outcomes (bleed, perforation, ischemic colitis, post-operative ileus) and hypersensitivity reactions.

*Results: 27 KTRs with hyperkalemia were treated with ZS-9 from 12/2019 – 10/2020. Mean age at transplant was 52 years. Median time to use since transplant was 0.75 years. Most patients were white (17, 63%) men (23, 85%). Diabetes mellitus (11, 41%) and glomerulonephritis (10, 37%) were the leading causes of end stage kidney disease. 5 (19%) patients were living donor recipients. Basiliximab (18, 67%) was the primary induction agent used. Most patients (22, 81%) were on standard triple maintenance immunosuppression. Mean baseline serum creatinine was 3.71 ± 2.84 mg/dL. 16 (59%) of the patients were inpatient. 6 (23%) had delayed graft function. 5 (19%) had slow graft function. Mean total ZS-9 used was 30 gm; mean doses utilized was 3. 9 patients were treated with ZS-9 within 30 days of transplant. The remaining 18 received ZS-9 thereafter. Primary outcomes wise, 6 patients (22%) required hemodialysis. 3 (50%) underwent hemodialysis for hyperkalemia. The mean decrease in K at ~48 hours was 0.8 ± 0.5 mmol/L. In steady state patients (n = 5), tacrolimus levels remained stable with the mean change of 1.3 ± 0.7 ng/mL. Patients were also able to remain on potassium raising medications e.g. prophylactic (n=4) and treatment (n =1 for Pneumocystis pneumonia, 1 for Nocardiosis) dosed trimethoprim-sulfamethoxazole, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/mineralocorticoid receptor antagonists (n=4), treatment dosed heparin (n=2), and azoles (n=2). Safety wise, no major adverse outcomes were observed. Edema is a concern but could not be assessed precisely due to multiple, dynamic factors driving fluid status in this population.

*Conclusions: Sodium zirconium cyclosilicate appears to be an effective, safe medication in KTRs. More studies are needed to characterize its use in the kidney transplant population.

« Back to 2021 American Transplant Congress