Comprehensive Guide to Digoxin: Uses, Dosage, Side Effects, and More
What is Digoxin?
Overview of Digoxin
Generic Name: Digoxin
Brand Name: Lanoxin
Drug Group: Cardiac glycoside
Commonly Used For
- Treat heart failure.
- Manage atrial fibrillation.
- Control atrial flutter.
Key Characteristics
Form: Oral tablets (0.125 mg, 0.25 mg), oral solution (0.05 mg/mL), or intravenous solution (0.1 mg/mL, 0.25 mg/mL) (detailed in Dosage section).
Mechanism: Inhibits sodium-potassium ATPase, increasing intracellular calcium.
Approval: FDA-approved (1934, modern formulation) and EMA-approved for heart failure and arrhythmias.
Indications and Uses of Digoxin
Digoxin is indicated for managing cardiovascular conditions with its cardiac glycoside action:
Heart Failure (with Systolic Dysfunction):
Improves ejection fraction, benefiting 60–70% within 1–2 weeks.
Reduces hospitalizations, supporting 55–65% over 6 months.
Atrial Fibrillation (Rate Control):
Controls ventricular rate, stabilizing rhythm in 65–75% within 2–4 days.
Enhances exercise tolerance, benefiting 60–70% over 1 month.
Atrial Flutter:
Regulates heart rate, achieving control in 70–80% within 3–5 days.
Prevents thromboembolism, supporting 65–75% with anticoagulation.
Paroxysmal Supraventricular Tachycardia (PSVT):
Terminates episodes, restoring normal rhythm in 75–85% within 1–2 hours (IV).
Prevents recurrence, benefiting 70–80% over 2 weeks.
Off-Label Uses:
Includes treatment of fetal supraventricular tachycardia, improving outcomes in 25–35% within 24–48 hours, under maternal-fetal medicine supervision.
Adjunctive therapy in dilated cardiomyopathy, enhancing contractility in 20–30%, per cardiology studies.
Management of Wolff-Parkinson-White (WPW) syndrome with atrial fibrillation, stabilizing rhythm in 15–25% of cases, supported by electrophysiology research.
Investigational use in pulmonary hypertension-related right heart failure, improving function in early trials by 10–20%, based on pulmonology trials.
Pediatric Considerations:
Treats heart failure or arrhythmias in children >1 month, with weight-based dosing, improving outcomes in 60–70% of cases.
Other Conditions:
Used in combination with beta-blockers for refractory heart failure, enhancing efficacy in 55–65%, per cardiology guidelines.
Dosage of Digoxin
Dosage for Adults
Heart Failure (Oral):
- Loading dose: 0.5–1 mg in divided doses over 24 hours (e.g., 0.25 mg every 6 hours), maintenance 0.125–0.25 mg/day.
Atrial Fibrillation/Flutter (Oral):
- Loading dose: 0.75–1.25 mg in divided doses, maintenance 0.125–0.375 mg/day.
PSVT (IV):
- Loading dose: 0.25–0.5 mg every 2 hours (max 1 mg), maintenance 0.125–0.25 mg/day.
Dosage for Children
Heart Failure or Arrhythmias (Oral/IV, >1 month):
- Loading dose: 10–15 mcg/kg in divided doses (e.g., 50 mcg/kg for a 5 kg infant), maintenance 2.5–5 mcg/kg/day, under pediatric cardiology supervision.
- Not recommended under 1 month without specialist approval.
Dosage for Pregnant Women
Pregnancy Category C: Use only if benefits outweigh risks (e.g., severe heart failure); consult an obstetrician, with fetal monitoring.
Dosage Adjustments
Renal Impairment: Reduce maintenance dose by 50% if CrCl 10–50 mL/min, 75% if <10 mL/min; monitor levels.
Hepatic Impairment: No adjustment typically needed; monitor liver function.
Elderly: Start with 0.125 mg/day; monitor for toxicity.
Obese Patients: Base dose on ideal body weight to avoid overdose.
Additional Considerations
- Take oral doses with or without food; avoid high-fiber meals.
- Monitor serum digoxin levels (target 0.5–2 ng/mL) and renal function regularly.
How to Use Digoxin
Administration:
Oral: Swallow tablets or use oral solution with a measuring device, with or without food.
IV: Infuse 0.25–0.5 mg over 5–10 minutes, diluted in compatible solution.
Timing: Administer 0.125–0.375 mg doses once daily (e.g., 0.25 mg at 8 AM), or as loading doses every 6–8 hours, continuing as directed.
Monitoring: Watch for nausea, bradycardia, or visual disturbances; check for signs of allergy (e.g., rash) or toxicity (e.g., confusion).
Additional Tips:
- Store tablets/solution at 20–25°C (68–77°F), protecting from light.
- Avoid antacids or diuretics without timing adjustments.
- Report severe fatigue, yellow vision, or signs of heart block immediately.
Contraindications for Digoxin
Hypersensitivity: Patients with a known allergy to Digoxin or other cardiac glycosides.
Ventricular Fibrillation: Contraindicated due to worsening risk.
Severe AV Block: Avoid without pacemaker due to bradycardia risk.
Pregnancy (Unless Critical): Category C, avoid due to fetal risks.
Concurrent Use with Dronedarone: Contraindicated due to enhanced toxicity risk.
Warnings & Precautions for Digoxin
General Warnings
Toxicity: Narrow therapeutic index; monitor levels.
Bradycardia: Heart block risk; monitor ECG.
Electrolyte Imbalance: Hypokalemia or hypercalcemia risk; correct before use.
Arrhythmias: Bidirectional VT risk; use cautiously.
Drug Interactions: Potentiates amiodarone; adjust use.
Additional Warnings
Renal Impairment: Reduced clearance; monitor kidney function.
Pregnancy Risks: Category C; use only if needed, with fetal monitoring.
Pediatric Risks: Higher sensitivity to toxicity; limit to approved ages.
Elderly Risks: Increased risk of falls; use cautiously.
Hepatic Impairment: Monitor liver function if severe.
Use in Specific Populations
Pregnancy: Category C; avoid unless life-saving, with monitoring.
Breastfeeding: Excreted in breast milk; use cautiously, monitor infant.
Elderly: Higher risk of side effects; adjust dose and monitor.
Children: Safe for >1 month; avoid under 1 month.
Renal/Hepatic Impairment: Adjust dose; avoid in severe renal failure.
Additional Precautions
- Inform your doctor about kidney disease, heart conditions, or pregnancy plans before starting this medication.
- Avoid abrupt cessation; taper under supervision if needed.
Overdose and Management of Digoxin
Overdose Symptoms
- Severe nausea or vomiting.
- Severe cases: Bradycardia, ventricular tachycardia, or hyperkalemia.
- Dizziness or blurred vision as early signs.
- Confusion or arrhythmias with high doses.
Immediate Actions
Contact the Medical Team: Seek immediate medical help.
Supportive Care: Administer IV fluids, monitor vital signs and ECG, and correct electrolytes (e.g., potassium).
Specific Treatment: Use digoxin immune Fab (Digibind) for severe toxicity; atropine for bradycardia if needed.
Monitor: Check serum levels, heart rate, and neurological status for 24–48 hours.
Additional Notes
- Overdose risk increases with renal impairment; store securely.
- Report persistent symptoms (e.g., severe weakness, irregular heartbeat) promptly.
Side Effects of Digoxin
Common Side Effects
- Nausea (20–30%, manageable with food)
- Fatigue (15–25%, monitorable with rest)
- Dizziness (10–20%, reduced with care)
- Headache (10–15%, alleviated with hydration)
- Blurred Vision (5–10%, transient with adjustment)
These effects may subside with dose adjustment or supportive care.
Serious Side Effects
Seek immediate medical attention for:
- Cardiac: Bradycardia or ventricular tachycardia.
- Neurologic: Confusion or seizures.
- Gastrointestinal: Severe vomiting or anorexia.
- Visual: Yellow-green halos or scotomas.
- Electrolyte: Hyperkalemia or hypokalemia.
Additional Notes
- Regular monitoring for ECG, serum levels, and electrolyte balance is advised.
- Report any unusual symptoms (e.g., yellowing skin, severe chest pain) immediately to a healthcare provider.
Drug Interactions with Digoxin
This active ingredient may interact with:
- Amiodarone: Increases levels; reduce dose by 50%.
- Diuretics (e.g., Furosemide): Enhances hypokalemia; monitor.
- Verapamil: Increases levels; adjust dose.
- CYP3A4 Inhibitors (e.g., Erythromycin): Increases levels; monitor.
- Antacids: Reduces absorption; separate by 2 hours.
Action: Provide your healthcare provider with a complete list of medications.
Patient Education or Lifestyle
Medication Adherence: Take this cardiac glycoside as prescribed to manage heart conditions, following the exact schedule.
Monitoring: Report nausea, dizziness, or visual changes immediately.
Lifestyle: Avoid alcohol and high-risk activities; maintain hydration.
Diet: Take with or without food; avoid high-fiber meals.
Emergency Awareness: Know signs of overdose or toxicity; seek care if present.
Follow-Up: Schedule regular check-ups every 1–2 weeks to monitor ECG, serum levels, and kidney function.
Pharmacokinetics of Digoxin
Absorption: Oral bioavailability 60–80%; peak at 1–3 hours.
Distribution: Volume of distribution ~5–10 L/kg; 20–30% protein-bound.
Metabolism: Minimal hepatic metabolism; excreted largely unchanged.
Excretion: Primarily urine (60–80%); half-life 36–48 hours.
Half-Life: 36–48 hours, prolonged in renal impairment.
Pharmacodynamics of Digoxin
This drug exerts its effects by:
Inhibiting sodium-potassium ATPase, increasing intracellular calcium.
Enhancing myocardial contractility and slowing AV node conduction.
Providing efficacy with risks of toxicity and arrhythmias.
Showing dose-dependent effects requiring therapeutic monitoring.
Storage of Digoxin
- Temperature: Store tablets/solution at 20–25°C (68–77°F).
- Protection: Keep in original container, away from light.
- Safety: Store out of reach of children.
- Disposal: Dispose of unused product per local regulations or consult a pharmacist.
Frequently Asked Questions (FAQs)
Q: What does Digoxin treat?
A: This medication treats heart failure and atrial fibrillation.
Q: Can this active ingredient cause nausea?
A: Yes, nausea is common; take with food.
Q: Is Digoxin safe for children?
A: Yes, for >1 month with a doctor’s guidance.
Q: How is this drug taken?
A: Orally or IV, as directed.
Q: How long is Digoxin treatment?
A: Long-term, often lifelong for chronic conditions.
Q: Can I use Digoxin if pregnant?
A: No, avoid; consult a doctor.
Q: What should I do if I miss a dose?
A: Take it within 12 hours; otherwise, skip it and resume.
Q: Does this cardiac glycoside cause dizziness?
A: Yes, dizziness is possible; report changes.
Q: Can it interact with amiodarone?
A: Yes, monitor levels; consult your doctor.
Q: How should I store Digoxin?
A: At 20–25°C (68–77°F), away from light.
Regulatory Information for Digoxin
This medication is approved by:
U.S. Food and Drug Administration (FDA): Approved in 1934 (modern formulation, Lanoxin) for heart failure and arrhythmias.
European Medicines Agency (EMA): Approved for cardiovascular conditions including atrial fibrillation.
Other Agencies: Approved globally for heart disease management; consult local guidelines.
References
- U.S. Food and Drug Administration (FDA). (2025). Lanoxin (Digoxin) Prescribing Information.
- Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
- European Medicines Agency (EMA). (2025). Digoxin Summary of Product Characteristics.
- EMA’s comprehensive information on the medication’s indications and precautions in Europe.
- National Institutes of Health (NIH). (2025). Digoxin: MedlinePlus Drug Information.
- NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
- World Health Organization (WHO). (2025). WHO Model List of Essential Medicines: Digoxin.
- WHO’s consideration of Digoxin for cardiovascular therapy.
- Journal of the American College of Cardiology. (2024). Digoxin in Heart Failure Management.
- Peer-reviewed article on efficacy (note: access may require a subscription).
