Hyperkalemia treatment standard.

Hyperkalemia is a common electrolyte disturbance in both inpatient and outpatient clinical practice. The severity and associated risk depends on the underlying cause and rate of potassium (K+) increase. Acute hyperkalemia requires immediate attention due to potentially life-threatening manifestations resulting from the rapid increase in plasma K+ concentration. Treatment is initially focused on stabilizing the cardiac membrane, followed by maneuvers to shift K+ into the cells, and ultimately initiating strategies to decrease total body K+ content. Chronic hyperkalemia develops over a more extended period of time and manifestations tend to be less severe. Nevertheless, the disorder is not benign since chronic hyperkalemia is associated with increased morbidity and mortality. The approach to patients with chronic hyperkalemia begins with a review of medications potentially responsible for the disorder, ensuring effective diuretic therapy and correcting metabolic acidosis if present. The practice of restricting foods high in K+ to manage hyperkalemia is being reassessed since the evidence supporting the effectiveness of this strategy is lacking. Rather, dietary restriction should be more nuanced, focusing on reducing the intake of nonplant sources of K+. Down-titration and/or discontinuation of renin-angiotensin-aldosterone inhibitors should be discouraged since these drugs improve outcomes in patients with heart failure and proteinuric kidney disease. In addition to other conservative measures, K+ binding drugs and sodium-glucose cotransporter 2 inhibitors can assist in maintaining the use of these drugs.

Potassium-lowering effects of sodium zirconium cyclosilicate in the early post-transplant period.

PROBLEM: Hyperkalemia is a serious condition among intra-abdominal transplant recipients, and the safety and efficacy of sodium zirconium cyclosilicate (SZC) for its management during the early post-transplant period are not well-established. METHODS: Adults who received at least one 10-g dose of SZC within 14 days after an intra-abdominal transplant between January 2020 and July 2022 were included in our study. The primary outcome was the change in potassium (K+) levels following the first SZC dose. Other analyses explored adjunctive potassium-lowering therapies, potential gastrointestinal complications, and patient subgroups based on therapy and transplant type. RESULTS: Among the recipients (n = 46), 11 were kidney recipients, 26 were liver recipients, seven were simultaneous liver/kidney recipients, and two were simultaneous pancreas/kidney recipients. The mean time to first dose post-transplant was 7.6 (±4) days, and the mean change in serum K+ after the initial SZC dose was -.27 mEq (p = .001). No gastrointestinal complications were observed following the SZC dose. The mean increase in serum bicarbonate was .58 mEq (p = .41) following the first dose of SZC. Four kidney recipients required dialysis following the SZC dose. CONCLUSION: This study represents the largest investigation on the use of SZC in transplant recipients. A single 10-g dose of SZC reduced serum K+ levels in all subgroups, while the use of adjunctive K+-lowering therapies did not provide additional reduction beyond the effects of SZC. Importantly, no gastrointestinal complications were observed. These findings suggest that SZC may be a safe and promising therapeutic option for hyperkalemia management following solid organ transplantation.

Hyperkalaemia in Cardiological Patients: New Solutions for an Old Problem.

Hyperkalaemia is one of the most common electrolyte disorders in patients with cardiovascular disease (CVD). The true burden of hyperkalaemia in the real-world setting can be difficult to assess, but in population-based cohort studies up to 4 in 10 patients developed hyperkalaemia. In addition to drugs interfering with potassium metabolism and food intake, several conditions can cause or worsen hyperkalaemia, such as advanced age, diabetes, and chronic kidney disease. Mortality, cardiovascular morbidity, and hospitalisation are higher in patients with hyperkalaemia. Hyperkalaemia represents a major contraindication or a withholding cause for disease-modifying therapies like renin-angiotensin-aldosterone inhibitors (RAASi), mainly mineralocorticoid receptor antagonists. Hyperkalaemia can be also classified as acute and chronic, according to the onset. Acute hyperkalaemia is often a life-threatening emergency requiring immediate treatment to avoid lethal arrhythmias. Therapy goal is cell membrane stabilisation by calcium administration, cellular intake, shift of extracellular potassium to the intracellular space (insulin, beta-adrenergic agents, sodium bicarbonate), and increased elimination with diuretics or dialysis. Chronic hyperkalaemia was often managed with dietary counselling to prevent potassium-rich food intake and tapering of potassium-increasing drugs, mostly RAASi. Sodium polystyrene sulphonate, a potassium binder, was the only therapeutic option. Recently, new drugs such as patiromer and sodium zirconium cyclosilicate give new opportunities for the treatment of hyperkalaemia, as they proved to be safe, well tolerated, and effective. Aim of this review is to describe the burden of hyperkalaemia in cardiovascular patients, its direct and indirect effects, and the therapeutic options now available in the acute and chronic setting.

Safety and efficacy of sodium zirconium cyclosilicate for the management of acute and chronic hyperkalemia in children with chronic kidney disease 4-5 and on dialysis.

BACKGROUND: Sodium zirconium cyclosilicate (SZC), an ion-exchange resin, is effective in the control of hyperkalemia in adults with chronic kidney disease (CKD); reports of use in children are limited. Prolonged therapy with SZC to relax dietary potassium restriction in CKD has not been examined. METHODS: We conducted a retrospective chart review of patients 6 months to 18 years of age with CKD stage 4-5 or on dialysis (5D) administered SZC for sustained hyperkalemia (potassium ≥ 5.5 mEq/L, three consecutive values). Patients received SZC (0.5-10 g per dose; age-based) either short-term (< 30 days) or long-term (> 30 days). RESULTS: Twenty patients with median age 10.8 (inter-quartile range 3.9, 13.4) years were treated with SZC. Short-term SZC, for 5 (3, 19) days, was associated with safe management of dialysis catheter insertions (n = 5) and access dysfunction (n = 4), and was useful during palliative care (n = 1). Serum potassium levels decreased from 6.7 (6.1, 6.9) to 4.4 (3.7, 5.2) mEq/L (P < 0.001). Long-term SZC for 5.3 (4.2, 10.1) months achieved decline in serum potassium from 6.1 (5.8, 6.4) to 4.8 (4.2, 5.4) mEq/L (P < 0.001). SZC use was associated with liberalization of diet (n = 6) and was useful in patients with poor adherence to dietary restriction (n = 3). Adverse events or edema were not observed; serum sodium and blood pressure remained stable. CONCLUSIONS: SZC was safe and effective for the management of acute and chronic hyperkalemia in children with CKD4-5/5D. Its use was associated with relaxation of dietary potassium restriction. Studies to examine its routine use to improve diet and nutritional status in children with CKD are required.

Cost-effectiveness of sodium zirconium cyclosilicate for advanced chronic kidney patients in Singapore.

INTRODUCTION: Hyperkalaemia (HK) is prevalent among patients with chronic kidney disease (CKD) and chronic heart failure, especially if they are treated with renin-angiotensin-aldosterone system inhibitors (RAASi). This study evaluated the cost-effectiveness of a newly developed anti-HK therapy, sodium zirconium cyclosilicate (SZC), to the current standard of care for treating HK in advanced CKD patients from the Singapore health system perspective. METHODS: We adapted a global microsimulation model to simulate individual patients' potassium level trajectories with baseline potassium ≥5.5 mmol/L, CKD progression, changes in treatment, and other fatal and non-fatal events. Effectiveness data was derived from ZS-004 and ZS-005 trials. Model parameters were localised using CKD patients' administrative and medical records at the Singapore General Hospital Department of Renal Medicine. We estimated the lifetime cost and quality-adjusted life years (QALYs) of each HK treatment, and the incremental cost-effectiveness ratio of SZC. RESULTS: SZC demonstrated cost-effectiveness with an incremental cost-effectiveness ratsio of SGD 45 068 per QALY over a lifetime horizon, below the willingness-to-pay threshold of SGD 90 000 per QALY. Notably, SZC proved most cost-effective for patients with less severe CKD who were concurrently using RAASi. Sensitivity analyses confirmed the robustness of the findings, accounting for alternative parameter values and statistical uncertainty. CONCLUSION: This study establishes the cost-effectiveness of SZC as a treatment for HK, highlighting its potential to mitigate the risk of hyperkalaemia and optimise RAASi therapy. These findings emphasise the value of integrating SZC into the Singapore health system for improved patient outcomes and resource allocation.

Effect of Concomitant Drugs on Sodium Zirconium Cyclosilicate Hydrate in Artificial Intestinal Juice.

To explore drug interactions involving sodium zirconium cyclosilicate hydrate (SZC) and concomitant drugs like calcium antagonists (amlodipine and nifedipine) and ß-blockers (carvedilol and bisoprolol), we investigate how these concomitant drugs influenced the administration of SZC in an artificial intestinal juice. Initially, we assessed the potassium ion adsorption capacity, ranking it as follows: calcium polystyrene sulfonate (CPS, 54.9 mg/g) < sodium polystyrene sulfonate (SPS, 62.1 mg/g) < SZC (90.8 mg/g). However, the adsorption equilibrium was achieved in the order of CPS ≒ SPS (within 1 min) < SZC (within 1 h). Subsequently, we determined the residual percentages of amlodipine, nifedipine, carvedilol, and bisoprolol, finding them to be 79.0-91.9% for SZC, 0.38-38.4% for SPS, and 0.57-29.0% for CPS. These results suggest the efficacy of SZC in managing hyperkalemia alongside concomitant drugs in an artificial intestinal juice, with particular emphasis on amlodipine (calcium antagonist) and carvedilol (ß-blocker). Additionally, we identified the presence of carbon, nitrogen, and oxygen components from both drugs on the SZC surface following interaction. We also evaluated how amlodipine, nifedipine, carvedilol, and bisoprolol affected the administration of SZC in the presence of potassium ions. Our results indicate that potassium ions and concomitant drugs did not interfere with each other in the artificial intestinal juice. These results offer valuable insights into the administration of SZC in conjunction with concomitant drugs. Lastly, the presented data shows qualitative results in this study.

Steroidal or non-steroidal MRAs: should we still enable RAASi use through K binders?

Renin-angiotensin-aldosterone system inhibitors (RAASi) and mineralocorticoid receptor antagonists (MRAs) are important interventions to improve outcomes in patients with chronic kidney disease and heart failure, but their use is limited in some patients by the development of hyperkalemia. The risk of hyperkalemia may differ between agents, with one trial showing lower risk of hyperkalemia with the novel non-steroidal MRA finerenone compared with steroidal MRA spironolactone. Novel potassium binders, including patiromer and sodium zirconium cyclosilicate, are available interventions to manage hyperkalemia and enable continuation of RAASi and MRAs in patients who could benefit from these treatments. These agents bind free potassium ions in the lumen of the gastrointestinal tract to prevent the absorption of dietary potassium and increase potassium secretion. Several studies showed that potassium binders are effective compared with placebo for preventing hyperkalemia or steroidal MRA discontinuation, but none has evaluated whether this strategy impacts clinically important endpoints such as cardiovascular events. Due to this and other limitations related to cost, clinical availability, pill burden and patient selection, alternative potential strategies to mitigate hyperkalemia may be more practical. Conservative strategies include increased monitoring and use of loop or thiazide diuretics to increase urinary potassium excretion. Non-steroidal MRAs may have a lower risk of hyperkalemia than steroidal MRAs and have stronger anti-inflammatory and anti-fibrotic effects with resultant reduced risk of kidney disease progression. Sodium-glucose cotransporter-2 inhibitors also decrease hyperkalemia risk in patients on MRAs and decrease cardiovascular events and kidney disease progression. These may be better first-line interventions to obviate the need for potassium binders and offer additional benefits.

Effectiveness of Patiromer Versus Sodium Zirconium Cyclosilicate for the Management of Acute Hyperkalemia.

BACKGROUND: Patiromer and sodium zirconium cyclosilicate (SZC) are 2 oral potassium binders approved for chronic hyperkalemia. It is unknown if one is more effective at reducing serum potassium than the other in acute hyperkalemia. OBJECTIVE: The objective of this study was to determine if there was a difference between patiromer and SZC in the reduction of serum potassium in patients with acute hyperkalemia. METHODS: This was a single-center, retrospective, observational study. Patients with a nonhemolyzed serum potassium level of 5.5 mEq/L or greater and received at least one dose of patiromer or SZC were included. The primary outcome was to determine the difference in effectiveness between patiromer and SZC in lowering of serum potassium 6 to 24 hours after administration. Secondary outcomes included description of total dosage received in 24 hours and incidence of electrolyte changes. RESULTS: A total of 200 patients were included in this study, with 100 patients in each group. Serum potassium was significantly reduced by both patiromer (-1.2 mEq/L, 95% confidence interval [CI]: -2.3 to -0.2) and SZC (-0.8 mEq/L, 95% CI: -1.0 to -0.7), but there was no difference between the 2 medications in the amount of potassium reduction (P = 0.464). No clinically significant differences in electrolyte changes were seen. CONCLUSIONS AND RELEVANCE: This study represents the first head-to-head comparison of patiromer and SZC in the setting of acute hyperkalemia. No difference in effectiveness between patiromer and SZC in reducing serum potassium was seen. Both agents can be considered in acute hyperkalemia management.

Single Dose of Sodium Zirconium Cyclosilicate Versus Sodium Polystyrene Sulfonate in Hospitalized Patients With Hyperkalemia.

BACKGROUND: Sodium zirconium cyclosilicate (SZC) is an inorganic zirconium silicate compound that selectively exchanges potassium for hydrogen and sodium. "Once" doses of SZC (with option to redose) in patients with hyperkalemia in hospitalized settings have not been evaluated. We hypothesized that a once dose of SZC would be non-inferior to sodium polystyrene sulfonate (SPS) in reducing serum potassium. OBJECTIVE: The objective of our study is to evaluate the effect of a "once" dose of SZC when compared with SPS in reducing serum potassium levels. METHODS: This was a retrospective analysis of patients who received either a "once" dose of SZC or single or repeated doses of SPS for hyperkalemia. The primary endpoint was mean absolute reduction in the first serum potassium value at least 4 hours after administration. The secondary efficacy endpoints were the rate of additional potassium-lowering therapies and the rate of normokalemia within 48 hours. Safety endpoints were the incidence of electrolyte abnormalities, hypoglycemia, hypertension, hypotension, and colonic necrosis. RESULTS: A total of 260 patients were included in the analysis. The mean initial serum potassium was similar between groups (5.6 ± 0.4). The absolute serum potassium reduction was -0.88 ± 0.64 mEq/L and -0.75 ± 0.65 mEq/L with SZC and SPS, respectively. The "once" regimen of SZC demonstrated non-inferiority compared with SPS (P < 0.0001). The proportion of patients achieving normokalemia within 48 hours and the proportion of patients receiving additional potassium-lowering therapies did not differ between groups. CONCLUSION AND RELEVANCE: The "once" dose regimen (with redose option) of SZC was non-inferior to the "once" or repeated dosing regimen of SPS with regard to absolute potassium reduction. There were no significant differences in the rate of additional potassium-lowering therapies and the rate of normokalemia at 48 hours. The incidence of hypertension was less common among patients who received SZC.

Therapeutic update on oral potassium exchange resin use in chronic kidney disease patients: a systematic review of randomized controlled clinical trials.

Hyperkalemia is a common electrolyte disorder in patients with chronic kidney disease (CKD) that increases in prevalence with the decline of glomerular fltration rate (GFR). Another risk of hyperkalemia is the use of renin-angiotensin-aldosterone system inhibitors (RAASi) and/or mineralocorticoid receptor antagonists (MRAs) in managing CKD and proteinuria. The treatment of chronic hyperkalemia is challenging especially for outpatients. Treatment options for hyperkalemia include the potassium exchange resins of which two new potassium binders, Patiromer Sorbitex Calcium, and Sodium Zirconium Cyclosilicate (SZC) have demonstrated their clinical efficacy in reducing serum potassium with a positive safety profile. The old potassium exchange resin sodium polystyrene sulfonate (Kayexalate™) has some negative side effects including colonic necrosis, hypomagnesemia, and hypernatremia. In this review and literature search, we compare the available oral potassium exchange resins, highlight their advantages and disadvantages and comment on efficacy and safety parameters specifically in CKD patients.

Sodium polystyrene sulfonate versus sodium zirconium cyclosilicate for the treatment of hyperkalemia in the emergency department.

BACKGROUND: Hyperkalemia accounts for over 800,000 emergency department (ED) visits in the United States each year, and has been associated with significant morbidity and mortality likely due to fatal cardiac dysrhythmias. Previous studies have demonstrated reductions in mortality when potassium levels are normalized in the ED. Cation exchange resins, such as sodium polystyrene sulfonate (SPS) and sodium zirconium cyclosilicate (SZC), may be administered as a means of definitively eliminating potassium from the body. This practice is based on physician preference and is not supported by high quality data. Two studies evaluating the use of cation exchange resins versus standard treatment in the ED demonstrated reductions in serum potassium levels within two hours of administration; however, there have been no published studies investigating these agents in a head-to-head comparison. OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of SPS versus SZC in lowering serum potassium in patients presenting to the ED with hyperkalemia. METHODS: This was an institutional review board-approved, retrospective cohort study conducted at a single-site ED. All patients who received medications under the "ED Hyperkalemia Treatment" order set between August 26, 2019 and May 13, 2021 were eligible for inclusion. The primary outcome was the change in serum potassium from baseline to first repeat level following SPS or SZC administration in the ED. RESULTS: A total of 885 patients were screened with 54 patients in the SPS group and 51 patients in the SZC group included in the final analyses. The mean change in serum potassium from baseline to first repeat level following administration of the cation exchange resin was -1.1 mEq/L for both groups. CONCLUSION: Administration of SPS or SZC for the treatment of hyperkalemia in the ED resulted in similar reductions in serum potassium.

A randomized study to compare oral potassium binders in the treatment of acute hyperkalemia.

BACKGROUND: The KBindER (K+ Binders in Emergency Room and hospitalized patients) clinical trial is the first head-to-head evaluation of oral potassium binders (cation-exchange resins) for acute hyperkalemia therapy. METHODS: Emergency room and hospitalized patients with a blood potassium level ≥ 5.5 mEq/L are randomized to one of four study groups: potassium binder drug (sodium polystyrene sulfonate, patiromer, or sodium zirconium cyclosilicate) or nonspecific laxative (polyethylene glycol). Exclusion criteria include recent bowel surgery, ileus, diabetic ketoacidosis, or anticipated dialysis treatment within 4 h of treatment drug. Primary endpoints include change in potassium level at 2 and 4 h after treatment drug. Length of hospital stay, next-morning potassium level, gastrointestinal side effects and palatability will also be analyzed. We are aiming for a final cohort of 80 patients with complete data endpoints (20 per group) for comparative statistics including multivariate adjustment for kidney function, diabetes mellitus, congestive heart failure, metabolic acidosis, renin-angiotensin-aldosterone system inhibitor prescription, and treatment with other agents to lower potassium (insulin, albuterol, loop diuretics). DISCUSSION: The findings from our study will inform decision-making guidelines on the role of oral potassium binders in the treatment of acute hyperkalemia. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04585542 . Registered 14 October 2020.

Radiopacity of Sodium Zirconium Cyclosilicate in Computed Tomography: a case of a patient with Hyperkalemia and kidney disease.

Sodium Zirconium Cyclosilicate (SZC) is commonly used for treating hyperkalemia because it sequesters gastrointestinal potassium ions, thereby reducing serum potassium levels. However, a less-discussed aspect of SZC is its radiopacity on x-ray-based imaging techniques. The European Medicines Agency (EMA) has only vaguely addressed this issue. Radiopaque substances like SZC can interfere with diagnostic imaging, creating challenges for clinicians and radiologists. We present the case of a 34-year-old Italian male to illustrate these concerns.

Effects of different potassium-lowering regimens on acute hyperkalemia in hemodialysis patients: a real-world, retrospective study.

BACKGROUND: Hyperkalemia is a common and potentially life-threatening electrolyte disorder in maintenance hemodialysis (MHD) patients. This study aimed to evaluate the efficacy and safety of potassium-lowering regimens during treatment of acute hyperkalemia in MHD patients. METHODS: This retrospective real-world study (RWS) was conducted among 139 MHD patients. They were given different potassium-lowering regimens, viz. the insulin and glucose (IG) intravenous administration group (IG, 46 patients), the sodium polystyrene sulfonate group (SPS, 33 patients), the sodium zirconium cyclosilicate group (SZC, 38 patients), the IG + SZC group (22 patients). The primary efficacy end point was the rate of serum potassium decline at 2 h. The rates of adverse events were also compared. RESULTS: At 2 h, the mean ± SE change of serum potassium level was - 0.71 ± 0.32 mmol per liter (mmol/L) in IG group, - 0.43 ± 0.38 mmol/L in SPS group, - 0.64 ± 0.36 mmol/L in SZC group, - 1.43 ± 0.38 mmol/L in IG + SZC group (P < 0.01). The serum potassium level in IG + SZC group decreased more than that in the other three groups (P < 0.01), while the serum potassium level in SPS group decreased less than that in the other three groups (P < 0.05). There was no significant difference on the decrease of the serum potassium level between IG group and the SZC group (P = 0.374). The IG group and the IG + SZC group had higher rates of symptomatic hypoglycemia. The SPS group had significant decreases of serum calcium and serum magnesium after treatment. CONCLUSIONS: Among MHD patients with acute hyperkalemia, SZC had similar potassium-lowering efficacy with IG intravenous administration at 2 h and superior on convenience and side-effects.

Risk of Hospitalization for Heart Failure in Patients With Hyperkalemia Treated With Sodium Zirconium Cyclosilicate Versus Patiromer.

BACKGROUND: Sodium zirconium cyclosilicate (SZC) and patiromer were recently approved to treat hyperkalemia. Whether the initiation of SZC is associated with an increased risk of hospitalization for heart failure (HHF) compared with patiromer in routine practice remains unknown. METHODS AND RESULTS: We conducted a new-user cohort study of nondialysis adults who initiated SZC or patiromer using Optum's de-identified Clinformatics Data Mart Database from May 2018 to September 2020. We performed propensity score matching in a variable ratio to match each SZC initiator with up to 3 patiromer initiators. The primary outcome was HHF. Cox proportional hazards regression models generated hazard ratios with 95% confidence intervals in the propensity score-matched groups. The cohort included 1126 SZC initiators and 2839 propensity score-matched patiromer initiators. The mean age was 72 years old, approximately 30% had a history of HF, and 85% had chronic kidney disease stages 3-5. The SZC group had 88 cases of HHF (incidence rate 35.8 per 100 person-years), and the patiromer group had 245 cases of HHF (incidence rate 25.1 per 100 person-years). The rate of HHF was numerically higher in the SZC initiators than patiromer initiators (hazard ratio 1.22, 95% confidence interval 0.95-1.56), but did not reach statistical significance. Results were consistent across sensitivity and subgroup analyses. CONCLUSIONS: The initiation of SZC might be associated with an increased risk of HHF compared with patiromer in routine practice. Larger comparative studies are needed to evaluate the safety of SZC in routine practice more precisely.

Pragmatic diagnostic and therapeutic algorithms to optimize new potassium binder use in cardiorenal disease.

BACKGROUND: Pivotal randomized trials demonstrating efficacy, safety and good tolerance, of two new potassium binders (patiromer and sodium zirconium cyclosilicate) led to their recent approval. A major hurdle to the implementation of these potassium-binders is understanding how to integrate them safely and effectively into the long-term management of cardiovascular and kidney disease patients using renin angiotensin aldosterone system inhibitors (RAASi), the latter being prone to induce hyperkalaemia. METHODS: A multidisciplinary academic panel including nephrologists and cardiologists was convened to develop consensus therapeutic algorithm(s) aimed at optimizing the use of the two novel potassium binders (patiromer and sodium zirconium cyclosilicate) in stable adults who require treatment with RAASi and experience(d) hyperkalaemia in a non-emergent setting. RESULTS: Two dedicated pragmatic algorithms are proposed. The lowest intervention threshold (i.e. 5.1 mmol/L or greater) was the one used in the patiromer and sodium zirconium cyclosilicate) pivotal trials, both drugs being indicated to treat hyperkalaemia in a non -emergent setting. Acknowledging the heterogeneity across specialty guidelines in hyperkalaemia definition and thresholds to intervene when facing hyperkalaemia, we have been mindful to use soft language i.e. "it is to consider", not necessarily "to do". CONCLUSIONS: Providing the clinical community with pragmatic algorithms may help optimize the management of high-risk patients by avoiding the risks of both hyper and hypokalaemia and of suboptimal RAASi therapy.

Zirconium cyclosilicate: An oral sorbent for potassium, four decades in the making.

HemoCleanse collaborated with Dr. John Sherman and Union Carbide in the 1980s to develop a cation exchanger with high selectivity for potassium and ammonium, for use in a wearable artificial kidney. Synthetic zeolites had unexpected solubility in this application but by 2000, UOP (a sister company of Union Carbide) had developed zirconium cyclosilicate (SZC). HemoCleanse performed early animal studies of SZC as an oral sorbent. These showed remarkable binding characteristics. HemoCleanse then obtained the license for SZC for medical applications, helped to form ZS Pharma, and collaborated in further animal studies and clinical trials. AstraZeneca purchased ZS Pharma in 2015, and SZC (Lokelma®) has now become an effective treatment for hyperkalemia in patients with kidney failure and cardiac conditions.

Sodium zirconium cyclosilicate to increase lithium elimination.

Lithium is considered a mood stabilizer for bipolar affective disorders, but it has a narrow therapeutic index of 0.6-1.2 mEq/L. This can easily result in toxic levels after minimal changes in renal function or individual patient's pharmacokinetics. Lithium toxicity can arise with levels as low as 1.5 mEq, and there are limited therapeutic options to treat these patients presenting to the emergency department (ED). At therapeutic levels 95% of lithium is eliminated unchanged by the kidneys. However, previous literature has examined sodium polystyrene sulfonate (SPS) as an option to reduce lithium levels by binding the lithium cation and enhancing its excretion via the gastrointestinal tract. This suggests there may be an increased degree of non-renal clearance and altered toxicokinetics at supratherapeutic levels. However, SPS has been associated with intestinal necrosis and may cause treatment limiting hypokalemia, and is therefore not commonly recommended in treatment algorithms for lithium toxicity. A newer cation exchange resin, sodium zirconium cyclosilicate (SZC), may provide a safer alternative to SPS while also aiding in the clearance of lithium. We present a patient case where a patient with symptomatic acute-on-chronic lithium toxicity had increased clearance of lithium after a dose of SZC.

Potassium responses to sodium zirconium cyclosilicate in hyperkalemic hemodialysis patients: post-hoc analysis of DIALIZE.

BACKGROUND: Sodium zirconium cyclosilicate (SZC) is an effective and well-tolerated treatment for hyperkalemia in maintenance hemodialysis patients. In post-hoc analyses of the phase 3b DIALIZE study, we examined the spectrum of potassium responses to SZC. METHODS: Post-hoc analyses with SZC and placebo included: the number of long interdialytic interval (LIDI) visits during the 4-week evaluation period where patients attained pre-dialysis serum potassium (sK+) concentrations of 4.0-5.0 and 4.0-5.5 mmol/L; potassium gradient (the difference between pre-dialysis sK+ and dialysate potassium) at days 36, 43, 50, and 57, and change from baseline to the end of treatment (EOT) using categories of potassium gradient (1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 mmol/L). RESULTS: A greater proportion of patients achieved the ranges of pre-dialysis sK+ concentration with SZC versus placebo for ≥1, ≥ 2, ≥ 3, and 4 LIDI visits over 4 weeks; 23.7 and 48.5% of patients in the SZC group achieved pre-dialysis sK+ concentrations of 4.0-5.0 and 4.0-5.5 mmol/L, respectively, at all 4 LIDI visits. Baseline mean potassium gradient was similar with SZC and placebo. At day 57, mean (standard deviation) potassium gradient was 2.78 (0.08) mmol/L with SZC and 3.52 (0.08) mmol/L with placebo; mean difference (95% confidence interval) was - 0.74 mmol/L (- 0.97 to - 0.52). A greater reduction in potassium gradient category from baseline towards lower-risk categories at EOT was observed with SZC versus placebo. CONCLUSIONS: These analyses expand our knowledge of the spectrum of potassium responses with SZC in hyperkalemic hemodialysis patients. TRIAL REGISTRATION: NCT03303521 .

Hyperkalaemia and potassium binders: Retrospective observational analysis looking at the efficacy and cost effectiveness of calcium polystyrene sulfonate and sodium zirconium cyclosilicate.

WHAT IS KNOWN AND OBJECTIVE: Hyperkalaemia is a common medical emergency in patients admitted to hospital. There is a limited evidence base supporting some of the commonly applied treatment strategies. Although, NICE has recommended the use of sodium zirconium cyclosilicate (SZC) (TA599) and patiromer (TA623) in both acute and chronic hyperkalaemia, there is a limited evidence base for their use in acute hyperkalaemia in the hospital setting, particularly when compared to the present standard of care calcium polystyrene sulfonate (CPS). METHODS: A retrospective review of the electronic patient record system across our hospital over a 6-month period identified 138 patients who received either SZC (65 patients) or CPS (73 patients) to manage hyperkalaemia, investigating their efficacy and cost effectiveness. Results were analysed using simple descriptive statistics. Based on the results a naïve cost comparison between the two drugs was made. RESULTS AND DISCUSSION: CPS and SZC both effectively reduced plasm potassium concentrations in patients with hyperkalaemia (6.07 and 6.03 mmol/L respectively) by 1.17 mmol/L and 1.24 mmol/L taking a similar amount of time to work (2.97 days vs. 3 days). The principle causes of hyperkalaemia identified were acute kidney injury, medication, and chronic kidney disease. Cost comparison analysis which took into account raw product price and time needed to dispense medications revealed that CPS has slightly better cost effectiveness compared to SZC albeit at a cost of increased staff input. WHAT IS NEW AND CONCLUSION: Both CPS and SZC were equally effective at lowering acutely raised potassium concentrations. The cost difference between the two products appears to be small. Claims regarding the benefits of newer agents over older established medications need to be properly explored in randomized trials rather than being based on small scale non-comparative studies.