Sorbisterit powder (calcium polystyrene sulfonate) – not marketed in Serbia: information on this potassium-lowering medicine

Sorbisterit is a powder for oral or rectal suspension containing calcium polystyrene sulfonate, a cation-exchange resin. In the gut the resin releases calcium and binds potassium, which is then excreted in the stool, lowering blood potassium.

In EU countries where it is authorised, for example Belgium and the Netherlands (marketing authorisation holder Fresenius Medical Care), Sorbisterit is indicated according to the official Summary of Product Characteristics for hyperkalaemia in patients with acute or chronic kidney failure, including patients on dialysis. All information on this page comes from the official documents listed in the sources.

What is Sorbisterit, how does it lower potassium and what is available in Serbia?

Key facts about the medicine

What is Sorbisterit used for in countries where it is authorised?

For the treatment of high blood potassium (hyperkalaemia) in patients with acute or chronic kidney failure, including patients on dialysis. It does not act quickly enough for emergency treatment of severe hyperkalaemia (potassium above 6.5 mmol/L or ECG changes) – emergency measures or dialysis are needed then.

How is it used?

According to the Belgian Summary of Product Characteristics, the powder is mixed with liquid and taken with main meals, or given rectally (enema) when oral use is not possible. Dose and duration depend on daily blood potassium values; in children the dose is calculated by body weight. Oral use is not permitted in newborns.

This describes the official leaflet and is not individual advice – dosing is decided by a doctor according to the official instructions and laboratory results.

When must it not be used?

• low blood potassium (hypokalaemia)
• conditions associated with high calcium (e.g. hyperparathyroidism, multiple myeloma, sarcoidosis, metastatic cancer)
• hypersensitivity to the active substance or excipients
• obstructive bowel disease, reduced bowel motility or risk of colonic necrosis
• concomitant sorbitol
• newborns with reduced bowel motility

Important safety information from the official documents

• Sorbitol must not be used as a laxative with this medicine – the combination carries a risk of colonic necrosis.
• Intestinal stenosis, ischaemia, necrosis and perforation have been reported, some fatal; severe abdominal pain, vomiting, bloating or rectal bleeding require urgent assessment.
• Treatment should be stopped if constipation becomes significant.
• Excessive potassium loss (especially with digoxin), rising calcium and falling magnesium are possible – regular laboratory checks are needed.
• With oral use, take care not to inhale the suspension; take it sitting upright.
• Contains sucrose – relevant for diabetes and rare sugar intolerances.
• Interactions: take other oral medicines at least 3 hours before or after (6 hours with delayed gastric emptying); antacids and laxatives containing magnesium, aluminium or calcium may cause alkalosis; caution with digoxin, lithium, levothyroxine, ciprofloxacin, tetracyclines and diuretics.
• Pregnancy: data are limited – only if clinically justified; avoid breastfeeding unless necessary.
• Common side effects: raised calcium, low potassium and magnesium, nausea and vomiting; uncommonly constipation, diarrhoea and bowel obstruction.

What is available in Serbia?

No medicine containing polystyrene sulfonate was found in the National Register of Medicines 2021 or in the ALIMS authorisation lists 2019–2026. For hyperkalaemia in adults, LOKELMA® (sodium zirconium cyclosilicate, AstraZeneca, powder for oral suspension 5 g and 10 g, prescription-only, authorised on 10 May 2023) is available in Serbia. It is a different active substance with different dosing and warnings, so it is not a 1:1 replacement.

Any replacement is always decided by a doctor, based on laboratory results and other treatment.

Composition, packaging and manufacturer

• Active substance: calcium polystyrene sulfonate (759–949 mg per 1 g of powder, corresponding to about 1.8 mmol calcium).
• Excipients: sucrose, anhydrous citric acid.
• Pack (Belgium): 500 g plastic container with a 20 g measuring spoon.
• Marketing authorisation holder: Fresenius Medical Care Nephrologica Deutschland GmbH, Bad Homburg, Germany.

Storage

• Keep the container tightly closed and protected from moisture.
• Shelf life unopened 3 years; use within 3 months of first opening (Belgium).
• Keep out of the reach of children.

Frequently asked questions

Can Sorbisterit be bought in Serbia?

No. Sorbisterit has no valid marketing authorisation in Serbia and was not found in ALIMS registers and authorisation lists from 2019 to 2026.

What can replace Sorbisterit?

For hyperkalaemia in adults, LOKELMA® (sodium zirconium cyclosilicate) is authorised in Serbia. It is a different substance, so the choice and dose are decided by a doctor with blood potassium monitoring.

Why is Sorbisterit not taken at the same time as other medicines?

The resin can bind other medicines in the gut and reduce their absorption. Other oral medicines are therefore taken at least 3 hours before or after Sorbisterit, or 6 hours with delayed gastric emptying.

Can a laxative be taken with Sorbisterit?

Sorbitol must not be used with this medicine because of the risk of intestinal necrosis, and antacids or laxatives containing magnesium, aluminium or calcium can disturb the acid–base balance. If you are constipated, contact your doctor.

Sources

• FAMHP (Belgium) – Summary of Product Characteristics, Sorbisterit powder for oral/rectal suspension (Fresenius Medical Care, updated 08/2023)
• CBG-MEB (Netherlands) – Public Assessment Report, Sorbisterit (2009)
• ALIMS – Summary of Product Characteristics, LOKELMA® (sodium zirconium cyclosilicate, revised May 2023)
• ALIMS – List of new authorisations and renewals, 1 May – 30 June 2023 (LOKELMA®)
• ALIMS – National Register of Medicines 2021

Sources checked on: 23 October 2026.