An oral powder that lowers high potassium
Sodium zirconium cyclosilicate
An oral medicine used to lower high potassium levels in the blood by trapping potassium in the gut.
What is Sodium zirconium cyclosilicate?
Sodium zirconium cyclosilicate is a medicine used to treat high potassium in the blood (hyperkalaemia), which is common in people with kidney disease or heart failure and can affect the heart's rhythm. It works in the gut by trapping potassium so it is passed out in the stool rather than absorbed, lowering the potassium level in the blood. It is taken by mouth as a powder mixed with water. Because it contains sodium, it can cause fluid build-up and swelling (oedema) in some people. Potassium is checked with blood tests, as it can also be lowered too far.
Education and reference only. This is a plain-language guide to Sodium zirconium cyclosilicate — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Sodium zirconium cyclosilicate is a medicine used to lower high potassium levels in the blood, a condition called hyperkalaemia. High potassium often affects people with chronic kidney disease or heart failure, especially those on certain heart or blood-pressure medicines, and matters because it can upset the heart's rhythm. It is taken by mouth as a powder mixed with water and works inside the gut rather than being absorbed. It can be used both to bring a high potassium down and to keep it controlled over time, under medical supervision with blood tests.
How it works
Sodium zirconium cyclosilicate acts like a sieve in the gut that selectively traps potassium. By holding on to potassium inside the gut, it stops it being absorbed into the blood, so the potassium is carried out of the body in the stool and the blood level falls. In exchange it releases some sodium, which is why fluid build-up and swelling can occur in some people. Because it works in the gut and is not absorbed into the body, it is used regularly to keep potassium controlled, and levels are monitored so potassium is not lowered too far.
Company & origin
Originated / developed by: Specialist manufacturer.
A medicine used in the UK to treat high potassium levels in the blood, taken by mouth as a powder mixed with water.
Practical use
How to take Sodium zirconium cyclosilicate
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Mix the powder with water and stir well, then drink it straight away, as your team advises.
- Separate it from certain other medicines by a few hours if advised, as it can affect their absorption.
- Take it regularly as prescribed to keep potassium under control.
- Tell your team about any new swelling, weight gain or breathlessness, as it can cause fluid build-up.
- Go for your blood tests so potassium can be checked and kept in the right range.
Weighing it up
Advantages & disadvantages of Sodium zirconium cyclosilicate
Advantages
- Lowers high potassium in the blood and helps keep it under control over time.
- Taken by mouth and works in the gut without being absorbed into the body.
- Can be used both to bring potassium down and to maintain control.
Disadvantages
- Contains sodium, so it can cause fluid build-up and swelling (oedema) in some people.
- Can lower potassium too far, so blood tests are needed.
- May affect the absorption of some other medicines, so timing can need planning.
Practical use
Good to know
A point to watch with sodium zirconium cyclosilicate is that it contains sodium, so it can cause the body to hold on to fluid, leading to swelling (oedema), which matters particularly for people with heart failure or who need to watch their salt and fluid; tell your team about any new swelling or breathlessness. It is taken by mouth as a powder mixed with water and stirred well. It can lower potassium, so there is a chance of potassium going too low, and regular blood tests are used to keep it in the right range. Like other gut binders, it can affect how some other medicines are absorbed, so separating it from certain medicines by a few hours may be advised. It is used under medical supervision, both to bring potassium down and to keep it controlled.
Who should not take it / use with caution
- People who have had a serious allergic reaction to it should not take it.
- It is used with caution in people who must strictly limit sodium or fluid, such as some with heart failure, because of the swelling risk.
- It should be used under medical supervision with regular potassium blood tests.
Monitoring
- Regular blood tests to check potassium is in the right range and not too low.
- Watching for swelling, weight gain or breathlessness that could signal fluid build-up.
- Reviewing how well potassium is controlled over time.
Side effects
- Fluid build-up and swelling (oedema), linked to its sodium content.
- Potassium falling too low if the balance is not watched.
- Occasionally, mild tummy upset.
Key interactions
- It can affect how some other medicines are absorbed, so separating them by a few hours may be advised.
- Its sodium content may matter alongside medicines and conditions where fluid balance is important.
- Tell your team about all your medicines so timing can be planned safely.
Available as: A powder taken by mouth, mixed with water before drinking.
Answers
Sodium zirconium cyclosilicate: frequently asked questions
What is sodium zirconium cyclosilicate used for?
It is used to treat high potassium in the blood (hyperkalaemia) by trapping potassium in the gut so it is passed out instead of absorbed.
Why can it cause swelling?
It contains sodium, which it releases as it traps potassium, and this can make the body hold on to fluid, leading to swelling (oedema) in some people.
Can it lower potassium too much?
Yes, potassium can fall too low, which is why regular blood tests are used to keep it in the right range.
How is it taken?
It is taken by mouth as a powder mixed with water and stirred well, then drunk straight away.
Do I need to keep it apart from other medicines?
It can affect how some other medicines are absorbed, so your team may advise separating it from certain medicines by a few hours.
The wider class
About Potassium binder (for high potassium)
Sodium zirconium cyclosilicate belongs to the potassium binder (for high potassium) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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