Sodium zirconium in chronic hyperkalaemia (Guidelines)

What's new / Latest updates

04/09/25 (V1.1): Flowcharts re-formatted

Audience

All NHS Highland
Primary and secondary care
Adults only

Highland Formulary - Hyperkalaemia formulary options (Formulary) | Right Decisions

Sodium zirconium is indicated for chronic kidney disease (CKD) and heart failure patients (LVEF < 40%) with chronic hyperkalaemia, despite optimal adjunctive therapy, to facilitate maximum angiotension-aldosterone system (RAAS) blockade.

We know that there is compelling evidence to suggest that CKD patients, and patients with heart failure with reduced ejection fraction, benefit from RAAS blockade. Studies show a reduction in progression in disease, reduced mortality and a reduction in cardiovascular events.

Hyperkalaemia is a side effect of RAAS blockade, which often results in suboptimal dosing or discontinuation. This is despite the implementation of a reduced potassium diet, diuretics to promote potassium excretion and correction of CKD-related metabolic acidosis. Potassium binding agents may allow optimisation of RAAS inhibitors.

Sodium zirconium is an orally administered, non-polymer inorganic cation exchange crystalline compound. It works by capturing potassium cations in exchange for hydrogen and sodium cations in the GI tract, thereby reducing the amount of free potassium available to be absorbed. Potassium is excreted in the faeces resulting in a decrease in potassium levels.

In September 2020, SMC approved the restricted use of sodium zirconium for the management of patients with hyperkalaemia defined as potassium >6.0 mmol/L with chronic kidney disease 3b to 5 and/or heart failure, who would otherwise need to down-titrate or discontinue their renin-angiotension-aldosterone system (RAAS) inhibitor therapy to maintain a clinically acceptable potassium level.

Drugs commonly implicated in hyperkalaemia	Risk of hyperkalaemia increased in:
RAASi (Ace inhibitors, aldosterone II blockers, mineralocorticoid receptor antagonists)	Combination of drugs implicated in causing hyperkalaemia
Potassium supplements	Renal impairment
Potassium sparing diuretics	Diabetes mellitus
Trimethoprim / co-trimoxazole	The elderly
NSAIDs
Non selective beta blockers

Potassium requires to be carefully monitored.

Prescribing guidance for SZC in chronic hyperkalaemia

Inclusion criteria:

Adult patients attending a renal or cardiology clinic AND with CKD 3b-5 (with proteinuria) AND/OR heart failure LVEF <40%
AND be on suboptimal RAAS blockade or have had RAAS blockade stopped due to hyperkalaemia.

Exclusion criteria: Patients with acute hyperkalaemia in AKI and dialysis patients

After two weeks of Sodium zirconium cyclosilicate (SZC) treatment at 5g daily, patients can be advised to increase their RAASi dose.
Potassium should be measured 1 to 2 weeks after RAASi dose increase.

If potassium <4mmol/L:
Reduce SZC dose to 5g alternate days and recheck potassium in two to four weeks

If potassium 4 to 5.2mmol/L:
Continue on 5g daily

If potassium >5.2mmol/L:
Increase SZC dose to 10g once daily and recheck potassium in two to four weeks

Monitoring	Once in normal range, potassium should be checked every three to four months and the SZC adjusted as above
Side effects	Hypokalaemia, oedema related events, constipation, diarrhoea, nausea QT prolongation - during correction of hyperkalaemia, a lengthening of the QT interval may be observed
Counselling	Mix the contents of each 5g or10g sachet of powder with approximately 45mL of water and stir well. The powder will not dissolve, and the suspension should be taken while it is cloudy; if the powder settles it should be stirred again. Take with or without food. SZC is considered high in sodium, therefore, patients should be advised to reduce salt intake (as would be the case for all patients in whom inhibitors of the renin angiotensin system are indicated) and not to use "lo salt" Patients should be advised that SZC may be opaque to X-rays and, if undergoing any abdominal X-ray, they should let the radiographer know that they are on this drug.
Drug interactions	As SZC is not absorbed or metabolised by the body, and does not meaningfully bind to other medicinal products, there are limited effects on other medicinal products. SZC can transiently increase gastric pH. Administer at least 2 hours before or 2 hours after oral medications with clinically meaningful gastric pH dependent bioavailability. Examples: Azole antifungals (ketoconazole, itraconazole and posaconazole), anti-HIV drugs (atazanavir, neltinavir, indinavir, ritonavir, saquinavir, raltegravir, ledipasvir and rilpivirine) and tyrosine kinase inhibitors (erlotinib, dasatinib and nilotinib).

Escalation criteria within secondary care

Persistent hyperkalaemia despite dose adjustment as per guideline, deterioration in renal function, any adverse effects to treatment or failure of patient to attend for necessary monitoring. Don’t stop RAASi without letting renal or cardiology know.

Patient information

Self management information

Ensure patients on RAASi and diuretics receive a copy of sick day rules card (Medicines Sick Day Rules Card | Scottish Patient Safety Programme (SPSP) | ihub - Medicines Sick Day Rules Card)
Sodium zirconium should be stopped at the same time as RASSi medication and the renal or cardiology team should be contacted for further advice on potassium monitoring.

Abbreviations

CKD: chronic kidney disease
GI: gastrointestinal
K: potassium
RAAS: Renin-Angiotensin-Aldosterone System

Last reviewed: 28/08/2025

Next review date: 28/08/2028

Author(s): Renal , Cardiology.

Version: 1.1

Approved By: TAM subgroup of ADTC

Reviewer name(s): N Joss, Renal Consultant, N Shaw, Cardiology pharmacist, K McCulloch, Renal Pharmacist.

Document Id: TAM704