RESUMO
Potassium binders (Kayexalate® and Sorbisterit®) are commonly used to treat hyperkaliemia. They are made of sodium or calcium polystyrene sulfonate. Their use is associated with multiple adverse effects including ileocolonic (or more rarely upper digestive tract) injuries which can lead to necrosis or perforations. This side effect is mostly seen in patients with chronic kidney disease or constipation. It presents with abdominal pain, diarrhea or hematochezia. The diagnosis is made when the histo-logical analysis of samples from the erythematous or ulcerated digestive wall finds polystyrene sulfonate crystals embedded in the mucosa. This diagnosis can be suspected by taking a careful initial drug inventory, if the clinician is aware of this rare but serious adverse effect. The lack of specificity of clinical symptoms and endoscopic lesions makes this inventory even more essential. Treatment is mainly supportive and requires cessation of the drug, while surgery is inevitable in the most severe cases.