Overview
The Clinical Pattern
An older adult taking digoxin and a loop diuretic develops anorexia, nausea, and a newly irregular pulse.
An older adult taking digoxin and a loop diuretic develops anorexia, nausea, and a newly irregular pulse. The serum digoxin concentration is 1.1 ng/mL. The low value does not settle the case: if the patient has hypokalemia, renal decline, or a new dysrhythmia, digoxin toxicity remains a leading concern. The pattern to recognize is increased automaticity plus impaired conduction. Excess digoxin can make myocardial cells fire prematurely while its vagal and direct nodal effects slow impulse transmission. That combination explains why toxicity can produce both tachyarrhythmias and profound bradycardia or AV block in the same patient. The next step is not to chase a number; it is to assess perfusion, obtain an ECG and electrolytes, stop further digoxin, and determine whether life-threatening toxicity requires digoxin immune Fab.