Digoxin Toxicity

An older adult taking digoxin and furosemide develops anorexia, nausea, confusion, and a newly irregular pulse. The digoxin concentration is 1.8 ng/mL. That result does not make the presentation safe: potassium of 2.9 mEq/L can sensitize the myocardium enough to produce toxicity within the reported concentration range. Digoxin toxicity is therefore not a laboratory diagnosis defined by a cutoff. It is a clinical syndrome in which excessive pump inhibition and increased vagal activity create a dangerous combination: abnormal impulse generation alongside slowed or blocked conduction. The immediate priorities are rhythm, perfusion, potassium, renal function, exposure timing, and rapid consultation with a poison center when severe toxicity is possible.