Potassium Channel Syndrome Caused by Nicorandil in Chronic Kidney Disease: A Case Report and Literature Review

Nicorandil is an anti-anginal drug that is commonly used in the treatment of ischemic heart disease. Nicorandil acts as a nitrate donor and ATP-sensitive potassium channel agonist, inducing coronary artery vasodilation. Potassium efflux through ATP-sensitive potassium channels activated by nicorandil can cause refractory hyperkalemia, particularly in patients with chronic kidney disease (CKD). Here, we report the case of an 85-year-old man who presented with severe refractory hyperkalemia, despite proper medical management. His serum potassium level increased from 4.96 to 7.21 mEq/L 7 days after restarting nicorandil. Hyperkalemia resolved shortly after discontinuation of nicorandil, which was presumed to be the offending drug. Previously, a few cases reported nicorandil-induced hyperkalemia called potassium channel syndrome in patients with CKD, and hyperkalemia can be reversed by ceasing nicorandil or using sulfonyl urea drugs. Given that CKD patients may have several contributing factors to this adverse event, clinicians should be aware of the risk of nicorandil-induced hyperkalemia, and medication review and drug discontinuation should be considered.