A potassium-binding resin for high blood potassium
Polystyrene sulfonate
A potassium-binding resin taken to lower high levels of potassium in the blood.
What is Polystyrene sulfonate?
Polystyrene sulfonate is a potassium-binding medicine used to lower high levels of potassium in the blood, which can be dangerous for the heart. It works in the gut, swapping potassium for either calcium or sodium depending on which form is used, so the potassium is passed out in the stools. The most important risks are bowel problems, including constipation and, rarely, serious bowel damage, which is why it must not be given with sorbitol or to people with a blocked bowel. It also shifts other body salts, so it needs monitoring, and it should be separated in time from other medicines.
Education and reference only. This is a plain-language guide to Polystyrene sulfonate — 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
Polystyrene sulfonate is a powdery resin medicine used to lower a high level of potassium in the blood, a problem that can occur in kidney disease and with certain medicines and that can affect the heart. It comes in two forms: a calcium form (often called calcium resonium) and a sodium form, and the choice depends on the person's needs. It is taken by mouth, usually mixed in water, or sometimes given into the back passage as an enema. It works inside the gut rather than being absorbed into the body, and is used under medical supervision with blood tests.
How it works
Polystyrene sulfonate works inside the bowel. As it passes through the gut, the resin grabs hold of potassium and gives up either calcium or sodium in exchange, depending on which form is used. The potassium is then carried out of the body in the stools rather than being absorbed, which lowers the level of potassium in the blood. Because it acts in the gut and is not absorbed, its effects depend on it moving through the bowel normally; this is also why it can cause constipation and why it is not given when the bowel is blocked.
Company & origin
Originated / developed by: Various manufacturers.
A long-established potassium-binding medicine used in the UK to lower high levels of potassium in the blood, available in a calcium or a sodium form.
Practical use
How to take Polystyrene sulfonate
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth mixed in water as directed, or use it as an enema if your team has arranged this; it must never be mixed with sorbitol.
- Separate it in time from your other medicines, taking them several hours apart, as it can stop them being absorbed.
- Tell your team straight away about severe tummy pain, bloating, constipation or any bleeding from the back passage.
- Drink fluids and follow any advice on diet and bowel care, as it can cause constipation.
- Attend your blood tests, as it can change levels of potassium, calcium and other body salts.
Weighing it up
Advantages & disadvantages of Polystyrene sulfonate
Advantages
- Lowers a high blood potassium level, helping to protect the heart.
- Works inside the gut and is not absorbed into the body.
- Comes in a calcium or a sodium form so the right one can be chosen for the person.
Disadvantages
- Commonly causes constipation and, rarely, serious bowel damage.
- Must not be given with sorbitol or to anyone with a blocked bowel.
- Shifts other body salts and binds other medicines, so it needs monitoring and careful timing.
Practical use
Good to know
The most important things to know about polystyrene sulfonate concern the bowel. It commonly causes constipation, and rarely it has been linked to serious bowel damage, including a type of bowel injury that can be life-threatening. For this reason it must not be given together with sorbitol and must not be used in anyone with a blocked or non-working bowel, and any severe tummy pain, bloating or bleeding from the back passage should be reported urgently. Because it swaps potassium for calcium or sodium, it can shift other body salts: the sodium form can add to fluid and blood-pressure problems, and the calcium form can raise calcium, so blood tests are needed. It can also bind to other medicines in the gut, so other tablets should be taken well apart from it.
Who should not take it / use with caution
- People with a blocked or non-working bowel must not use it because of the risk of serious bowel damage.
- It must not be given together with sorbitol, which increases the risk of bowel injury.
- Newborn babies should not be given it by mouth, and it is used with caution in young infants.
- The sodium form is used with care in people who need to limit salt, such as those with heart failure, and the calcium form in those with high calcium.
Monitoring
- Regular blood tests to check potassium and other body salts such as calcium, sodium and magnesium.
- Watching for bowel problems, including constipation and signs of serious bowel damage.
- Reviewing the dose and the need to continue based on potassium levels.
Side effects
- Constipation, which can be troublesome and sometimes severe.
- Nausea, vomiting or loss of appetite.
- Changes in body salts, such as low magnesium or low potassium if too much is given, or raised calcium or sodium depending on the form.
- Rarely but seriously, severe bowel damage, including a dangerous type of bowel injury, which needs urgent care.
Key interactions
- It must not be combined with sorbitol because of the risk of serious bowel injury.
- It can bind to many other medicines in the gut and stop them being absorbed, so take them several hours apart.
- It can interact with antacids and some other medicines to affect body salts, so tell your team what you take.
Available as: A powder taken by mouth mixed in water, or given as an enema into the back passage.
Answers
Polystyrene sulfonate: frequently asked questions
What is polystyrene sulfonate used for?
It is used to lower a high level of potassium in the blood, which can be dangerous for the heart, by binding potassium in the gut so it is passed out in the stools.
Why must it not be given with sorbitol?
Giving it with sorbitol has been linked to serious bowel damage, so the two must not be combined.
What is the difference between the calcium and sodium forms?
Both lower potassium, but they swap it for different salts: the sodium form can add to fluid and blood-pressure problems, while the calcium form can raise calcium, so the right one is chosen for you.
Why do I have to take my other tablets at a different time?
It can bind to other medicines in the gut and stop them being absorbed, so other tablets should be taken several hours apart from it.
What bowel symptoms should I report?
Report severe tummy pain, bloating, ongoing constipation or any bleeding from the back passage urgently, as it can rarely cause serious bowel damage.
The wider class
About Potassium-binding resin
Polystyrene sulfonate belongs to the potassium-binding resin 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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