Hyperkalemia, if left untreated, can lead to sudden death from cardiac arrhythmias. Hyperkalemia is defined as a serum potassium concentration greater than 5.5 mEq/L. It may develop when potassium intake exceeds excretion or when the transcellular distribution of potassium is disturbed. 1,2 At our institution, hyperkalemia was the most common adverse drug event (ADE).The clinical presentation of hyperkalemia is related to the effects of high potassium levels on neuromuscular, cardiac, and smooth muscle cells. Symptoms include generalized fatigue, muscle weakness, twitching, paresthesias, nausea, cramping, paralysis, palpitations, and cardiac abnormalities. 1 Thrombocytosis, leukocytosis, hemolysis, sickle cell disease, renal insufficiency or failure, Addison's disease, hyporenin aldosteronism, pseudohypoaldosteronism, insulin resistance or deficiency, hypertonicity, rhabdomyolysis, burns, and trauma are common causes of hyperkalemia. 3 Medications can also cause hyperkalemia through different mechanisms. Drug-induced hyperkalemia can result from the use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), nonsteroidal antiinflammatory drugs (NSAIDS), aldosterone antagonists, potassium supplements, nonselective β-blockers, heparin (with prolonged use), tacrolimus, succinylcholine, penicillin G potassium, pentamidine, ketoconazole, cy-