Toxic synergism of disopyramide and hyperkalemia.

A patient is presented whose electrocardiogram became remarkably abnormal and who developed hypotension while receiving disopyramide and potassium. This report documents a potassium-disopyramide synergism leading to life-threatening toxicity. These abnormalities were corrected by glucose, insulin and bicarbonate therapy, suggesting that serious disopyramide toxicity may be enhanced by hyperkalemia and reversed by lowering the serum potassium.