Digoxin toxicity can cause life-threatening dysrhythmias,
hyperkalemia, and hemodynamic collapse. The presentation is often subtle, and management hinges on early recognition plus timely Fab administration.
At the Bedside
- Consider toxicity in: older adults, renal failure, dehydration, electrolyte derangements, dose changes, drug interactions (amiodarone, verapamil, macrolides, azoles), and intentional overdoses.
- Key symptoms: nausea/vomiting, anorexia, weakness, confusion, visual changes (yellow/green halos), bradycardia, AV block, atrial tachycardia with block, ventricular ectopy.
- Workup:
- ECG: any bradyarrhythmia, AV block, bidirectional VT, frequent ectopy; “scooped” ST changes are not diagnostic of toxicity.
- BMP/Mg/Ca, creatinine, glucose.
- Serum digoxin level: useful only when interpreted correctly; draw at least 6 hours after ingestion (earlier levels may mislead).
- Potassium is critical: hyperkalemia in acute toxicity is a marker of severe poisoning.
- Initial management:
- Stop digoxin and culprit interacting meds.
- Support ABCs, continuous cardiac monitoring.
- Treat hyperkalemia and dysrhythmias.
- Activated charcoal may be considered if early and airway protected (especially multiple-dose charcoal in some overdoses, but discuss with poison center).
- Definitive therapy:
- Digoxin immune Fab for:
- Life-threatening dysrhythmia
- Hemodynamic instability
- Significant hyperkalemia in acute poisoning
- Large ingestion / very high level with symptoms
- Intractable GI/neuro symptoms with concerning toxicity
- After Fab, serum digoxin levels become uninterpretable.
- Disposition:
- ICU for Fab recipients, dysrhythmias, significant electrolyte abnormalities, or symptomatic patients.
- Observe asymptomatic, low-risk patients with poison center guidance and serial ECG/electrolytes.
A Classic Presentation
A 78-year-old woman with CKD presents with nausea, confusion, and near-syncope after a recent increase in digoxin dose. ECG shows sinus bradycardia with intermittent AV block and frequent PVCs. Labs reveal K 6.2 mEq/L and creatinine above baseline. She is monitored, digoxin is held, poison center is called, and she receives digoxin immune Fab because of hyperkalemia plus conduction instability.
Study Directive
- Draw the digoxin toxicity pathway from memory: Na/K-ATPase inhibition → hyperkalemia, bradyarrhythmias, GI/neuro symptoms.
- Make a one-page “Fab indications” card and review it until you can recite it without notes.
- Practice interpreting 5 ECGs with digoxin toxicity patterns.
- Review how renal failure and drug interactions raise digoxin levels.
- Call up your poison center’s digoxin immune Fab dosing algorithm and save it in your notes.
Recent Literature