A Rare Case of Severe Hypokalemia and Hypomagnesemia due to Venetoclax and Polypharmacy Leading to Life-Threatening Cardiac Arrhythmias

Venetoclax is a novel agent used in hematologic malignancies. Although no long-term studies have directly implicated venetoclax, few studies show possible association with electrolyte abnormalities. Severe derangements in serum electrolyte levels can cause cardiac dysrhythmias, which can be potentially fatal. We present a case of venetoclax in association with the other medications causing life-threatening arrhythmias. Hypothesized mechanisms include damage to the distal tubules causing loss of potassium and magnesium. Our patient required modification of his medications and aggressive repletion of electrolytes with good outcomes. For patients on venetoclax, especially those with polypharmacy, caution should be exercised to prevent severe electrolyte derangements, which can lead to life-threatening arrhythmias.