Heart Failure Pregnancy: No data in pregnant women; animal studies show no direct or indirect reproductive toxicity. As a precautionary measure it is preferable to avoid use during pregnancy. Can be used during breast-feeding — not systemically absorbed and not expected to be excreted in breast milk (eMC §4.6).

Sodium Zirconium Cyclosilicate

Brand names: Lokelma

Used in: Hyperkalaemia

Sodium zirconium cyclosilicate is an oral non-absorbed potassium-binding agent used to treat hyperkalaemia, including in patients with heart failure or chronic kidney disease where renin-angiotensin inhibitors are desirable.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Correction phase: 10 g three times a day. Maintenance phase: 5 g once daily (starting maintenance dose), titrated between 5 g every other day and 10 g once daily

Route: Oral (powder suspended in water)

Frequency: Three times a day during correction; once daily during maintenance

Max: No more than 10 g once daily for maintenance therapy (UK SPC). For patients on chronic haemodialysis the dose may be adjusted weekly in 5 g increments up to 15 g once daily on non-dialysis days.

Hyperkalaemia (product in the fetched SPC is Lokelma). Correction phase: normokalaemia is typically achieved within 24 to 48 hours; if the patient is still hyperkalaemic after 48 hours the same regimen may continue for a further 24 hours; if normokalaemia is not achieved after 72 hours, other treatment approaches should be considered. Maintenance: establish the minimal effective dose to prevent recurrence; monitor serum potassium regularly. Missed dose: take the next usual dose at the normal time. Method of administration: empty the entire contents of the sachet(s) into a glass containing approximately 45 ml of water, stir well and drink while still cloudy — the powder does not dissolve; if it settles, stir again; rinse the glass with more water to ensure the whole dose is taken. May be taken with or without food. No dose changes needed for hepatic impairment or for the elderly. Paediatric: safety and efficacy in children and adolescents under 18 years have not been established and no data are available. Cross-check — the US label (openFDA) differs from the UK SPC on maintenance dosing: it states 10 g once daily for continued treatment, up-titrated at intervals of 1 week or longer in 5 g increments, with a recommended maintenance range of 5 g every other day to 15 g daily. NOTE: comparator symbols (less-than / greater-than) were stripped when the SPC text was captured — verify numeric thresholds against the source SPC.

Dose adjustments

Renal

No change from normal doses for patients with renal impairment who are not on chronic haemodialysis. For patients on dialysis, dose only on non-dialysis days: recommended starting dose 5 g once daily, titrated weekly up or down in 5 g increments up to 15 g once daily on non-dialysis days, based on the pre-dialysis serum potassium after the long inter-dialytic interval, targeting normokalaemia 4.0–5.0 mmol/L; monitor serum potassium weekly while adjusting.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance

Side effects

Hypokalaemia (very common; 4.1% had serum potassium below 3.5 mmol/L)
Oedema-related events (5.7%) including fluid retention, hypervolaemia and peripheral oedema — seen in the maintenance phase and more commonly at 15 g
Constipation (common; estimated 8.9% in studies in predominantly Asian populations)
Worsening of pre-existing heart failure (13.6% on treatment vs 5.7% on placebo in pooled non-dialysis studies)
Nausea, diarrhoea, abdominal pain/distension, vomiting; hypersensitivity reactions (rash, pruritus)

Interactions

Sodium zirconium cyclosilicate is not absorbed or metabolised and does not meaningfully bind other medicines, so effects on other medicines are limited
It can transiently increase gastric pH by absorbing hydrogen ions, altering the solubility and absorption kinetics of co-administered medicines with pH-dependent bioavailability
(US label §7 / §2.3) In general, give other oral medicines at least 2 hours before or 2 hours after sodium zirconium cyclosilicate
Medicines that affect serum potassium (RAAS inhibitors, diuretics) — monitor serum potassium after any change
May be opaque to X-rays — relevant if abdominal imaging is performed

Clinical monograph

How it works

It is an insoluble inorganic cation exchanger that selectively traps potassium ions in exchange for hydrogen and sodium throughout the gastrointestinal tract, increasing faecal potassium excretion and lowering serum potassium.

Prescribing in practice

It is not for emergency life-threatening hyperkalaemia because the onset is too slow — use established acute measures first and reserve this agent for ongoing control.
It can bind co-administered oral drugs with pH-dependent solubility, so separate other oral medicines from it in time as advised in the SPC.
Each dose adds a sodium load, which warrants caution in heart failure, hypertension or fluid overload, and it may cause oedema.

Monitoring

Monitor serum potassium during initiation and dose adjustment and periodically thereafter, watching also for hypokalaemia and signs of fluid retention.

Counselling the patient

Take other oral medicines separated in time from this binder as instructed.
Report ankle swelling or new breathlessness, which may indicate fluid retention.
Attend for the blood tests used to adjust your dose.

Evidence & guidelines

Randomised trials (HARMONIZE and related studies) demonstrated dose-dependent reductions in serum potassium and maintenance of normokalaemia, supporting its use for chronic hyperkalaemia management.

Reference: DIALIZE trial NEJM 2019; 380(18):1707-1716; NICE TA599; MHRA 2018; ESC HF Guidelines 2021; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Pathways