Educational use only. Drug cards are AI-assisted study material for NCLEX preparation.
Mechanism of action
Inhibits the Na+/K+ ATPase pump in cardiac myocytes, increasing intracellular calcium. The result is stronger contractions (positive inotropy) and slower conduction through the AV node (negative chronotropy). Used for heart failure and to control ventricular rate in atrial fibrillation.
Adverse effects
Life-threatening / NCLEX-tested
- Digoxin toxicity — life-threatening; therapeutic range is narrow (0.5–2.0 ng/mL)
- Bradycardia and heart block (any new AV block is a red flag)
- Ventricular arrhythmias (PVCs, bigeminy, V-tach)
- Visual disturbances — yellow-green halos around lights are classic for toxicity
- Confusion, delirium, especially in older adults
Side effects
Common — what to teach
- Anorexia, nausea, vomiting (often the first sign of toxicity)
- Diarrhea
- Headache
- Fatigue, weakness
- Dizziness
Food & drug interactions
Hypokalemia, hypomagnesemia, and hypercalcemia all increase the risk of digoxin toxicity — diuretics like furosemide are the classic offender. Amiodarone, verapamil, quinidine, and clarithromycin raise digoxin levels. Antacids and high-fiber meals can reduce absorption — separate doses by at least 2 hours. Monitor K+ closely whenever a patient is on digoxin plus a non-potassium-sparing diuretic.
Nursing implications
Assessment, monitoring, patient teaching
- Take an apical pulse for one full minute before every dose; hold and notify the provider if HR < 60 bpm in adults (< 70 in children, < 90 in infants)
- Monitor serum digoxin level (therapeutic 0.5–2.0 ng/mL), potassium, magnesium, and renal function
- Teach patients to report nausea, vomiting, vision changes (yellow halos), or palpitations immediately
- Take at the same time each day; do not double up on missed doses
- Have digoxin immune Fab (Digibind) available as the antidote for severe toxicity
- Reinforce that grapefruit and high-fiber meals can change absorption
When to hold / contraindications
- Apical HR < 60 bpm in adults
- Serum digoxin level > 2.0 ng/mL
- Serum potassium < 3.5 mEq/L (correct K+ first — hypokalemia drives toxicity)
- New onset of any heart block or ventricular arrhythmia
- Symptoms of toxicity: anorexia, vomiting, vision changes, confusion
Memory anchor
"Dig holds at 60 — and yellow halos mean call the provider." Therapeutic 0.5–2.0 ng/mL; low K+ + dig = toxicity.
Practice Digoxin questions
Test your recall on real NCLEX-style pharmacology questions — with full rationales and an AI Coach for the parts you miss.