Digoxin

Cardiac Glycoside

Generic Name

Digoxin

Drug Class

Cardiac glycoside; positive inotropic, negative chronotropic agent

Indications

Heart failure with reduced ejection fraction
Atrial fibrillation or atrial flutter (rate control)
Paroxysmal supraventricular tachycardia (adjunct therapy)

Dosage

Adults (oral): 0.125–0.25 mg once daily; may adjust based on renal function and serum digoxin levels
Adults (IV): 0.25 mg over 5 minutes; may repeat 6–8 hours if needed
Children: 10–15 mcg/kg/day in 2 divided doses (infants often lower); adjust carefully based on weight and cardiac condition

Note: Monitor serum digoxin levels, renal function, and electrolytes (especially K⁺, Mg²⁺, Ca²⁺) to avoid toxicity.

Route of Administration

Oral (tablet, solution), IV

Mechanism of Action

Digoxin inhibits the sodium-potassium ATPase pump in cardiac myocytes, increasing intracellular calcium. This enhances myocardial contractility (positive inotropy), slows AV nodal conduction, and decreases heart rate (negative chronotropy).

Common Adverse Effects

Bradycardia
Fatigue
GI upset (nausea, vomiting, diarrhea)
Visual disturbances (blurred or yellow vision)

Serious Adverse Effects

Cardiac arrhythmias (ventricular or atrioventricular block)
Severe bradycardia
Digoxin toxicity, especially with hypokalemia or renal impairment

Contraindications

Ventricular fibrillation
Hypersensitivity to digoxin
Second- or third-degree AV block (unless pacemaker present)
Wolf-Parkinson-White syndrome with AF

Precautions

Monitor heart rate, ECG, renal function, and electrolytes
Use with caution in elderly patients
Adjust dose carefully in renal impairment
Avoid hypokalemia, hypomagnesemia, and hypercalcemia to reduce risk of toxicity

Drug Interactions

Diuretics – may cause hypokalemia, increasing toxicity risk
Amiodarone, verapamil, quinidine – increase digoxin levels
Beta-blockers – additive bradycardia
Antacids or cholestyramine – may reduce digoxin absorption

Pregnancy & Lactation

Use only if clearly needed; crosses placenta and excreted in breast milk – monitor infant for bradycardia.

Patient Counseling

Take at the same time each day
Do not skip or double doses
Report dizziness, visual changes, palpitations, or fainting
Regularly monitor heart rate and labs