Introduction
Digoxin is a cardiac glycoside commonly used to manage various heart conditions, particularly atrial fibrillation and heart failure. Its mechanism of action involves increasing myocardial contractility and controlling heart rate, making it a valuable medication in cardiac care. However, due to its narrow therapeutic index and potential for toxicity, nursing professionals must exercise careful consideration, perform targeted interventions, and provide thorough health education to patients.
Digoxin Drug Summary Table
| Category | Details |
|---|---|
| Generic Name | Digoxin |
| Brand Names | Lanoxin, Digitek |
| Drug Class | Cardiac glycoside |
| Source | Extracted from Digitalis purpurea (foxglove plant) |
| Mechanism of Action | Inhibits Na⁺/K⁺-ATPase → ↑ intracellular Ca²⁺ → ↑ myocardial contractility |
| Therapeutic Uses | – Heart failure (systolic) – Atrial fibrillation (rate control) |
| Dosage Forms | Tablet, capsule, IV injection, oral solution |
| Therapeutic Range | 0.5–2.0 ng/mL (narrow therapeutic index) |
| Onset of Action | Oral: 30–120 min IV: 5–30 min |
| Peak Effect | Oral: 1–6 hrs IV: 1–4 hrs |
| Half-life | ~36–48 hours (longer in renal impairment) |
| Excretion | Primarily renal |
| Common Side Effects | Nausea, vomiting, dizziness, fatigue, visual changes (yellow/green halos) |
| Serious Adverse Effects | Bradycardia, AV block, ventricular arrhythmias, digoxin toxicity |
| Toxicity Signs | GI upset, confusion, blurred vision, arrhythmias |
| Antidote for Toxicity | Digoxin-specific antibody fragments (Digibind) |
| Drug Interactions | Diuretics, amiodarone, verapamil, quinidine, antacids |
Nursing Considerations for Digoxin Therapy
1.Assessment Prior to Administration
- Baseline Vital Signs: It is crucial to assess the patient’s baseline pulse rate, blood pressure, and rhythm before administering digoxin. The apical pulse should be counted for one full minute and documented.
- Renal Function: Since digoxin is primarily excreted by the kidneys, assess renal function through serum creatinine, blood urea nitrogen (BUN), and estimated glomerular filtration rate (eGFR). Impaired renal function increases the risk of digoxin toxicity.
- Electrolyte Levels: Monitor serum potassium, magnesium, and calcium levels. Hypokalaemia, hypomagnesaemia, and hypercalcaemia can increase the risk of toxicity.
- Drug History: Review the patient’s current medications for potential interactions, especially with diuretics, ACE inhibitors, beta-blockers, and other drugs affecting electrolyte balance or heart rate.
- Allergies and Medical History: Check for allergies and relevant comorbidities, such as thyroid disorders, which can affect digoxin sensitivity.
2. Indications and Contraindications
- Indications: Digoxin is indicated in heart failure (especially with reduced ejection fraction) and for rate control in atrial fibrillation and atrial flutter.
- Contraindications: Absolute contraindications include ventricular fibrillation, digoxin hypersensitivity, and certain forms of heart block. Caution is needed in patients with bradycardia, electrolyte imbalances, or renal impairment.
3. Dosage and Administration
- Digoxin can be administered orally or intravenously. The typical adult oral dose is 0.125–0.25 mg once daily, but dosing must be individualised based on age, renal function, and clinical response.
- For paediatric and elderly patients, lower doses are recommended due to increased sensitivity.
- Always use the same brand or formulation to maintain consistent bioavailability.
Nursing Interventions During Digoxin Therapy
1. Monitoring and Ongoing Assessment
- Pulse Monitoring: Prior to each dose, check the apical pulse for one full minute. Withhold digoxin and notify the physician if the pulse is below 60 bpm in adults, below 70 bpm in children, or below 90 bpm in infants.
- Electrolyte Monitoring: Regularly monitor serum potassium, magnesium, and calcium. Address any abnormalities promptly to reduce the risk of toxicity.
- ECG Monitoring: Watch for arrhythmias or changes in ECG patterns, such as prolonged PR interval, ST depression, or T-wave inversion, which may indicate toxicity.
- Signs of Toxicity: Be vigilant for symptoms such as nausea, vomiting, anorexia, visual disturbances (yellow-green halos, blurred vision), confusion, and cardiac arrhythmias.
- Renal Function Tests: Periodically assess renal function, especially in elderly or renally impaired patients.
2.Managing Adverse Effects and Toxicity
- Recognising Toxicity: Early signs include gastrointestinal disturbances, CNS effects (lethargy, confusion), and visual changes. Life-threatening toxicity may present as severe bradycardia or arrhythmias.
- Immediate Actions: If toxicity is suspected, withhold digoxin, monitor vital signs, and inform the healthcare provider immediately. Prepare to administer antidotes such as digoxin-specific antibody fragments (digoxin immune Fab) if indicated.
- Correct Electrolyte Imbalances: Administer potassium supplements for hypokalaemia if not contraindicated, and manage other electrolyte disturbances as per protocol.
- Supportive Care: Provide oxygen, cardiac monitoring, and intravenous fluids as needed.
3. Documentation and Communication
- Document all assessments, pulse rates, doses given, withheld doses, patient responses, and any adverse events.
- Communicate with the healthcare team regarding changes in the patient’s condition or laboratory values.
Health Education for Patients and Families
1. Purpose and Benefits of Digoxin
- Explain in simple terms why digoxin is prescribed (heart failure management, controlling irregular heartbeats).
- Discuss expected benefits, such as improved exercise tolerance and reduced symptoms of heart failure.
2. Dosage and Administration Instructions
- Taking Digoxin: Advise patients to take the medication at the same time every day. If a dose is missed, instruct them to take it as soon as remembered unless it is almost time for the next dose—never double up.
- Measuring Dose: For liquid formulations, demonstrate correct measurement techniques using appropriate devices.
- Storage: Store tablets or liquids in a cool, dry place away from children.
3. Recognising and Reporting Side Effects
- Educate about the signs and symptoms of digoxin toxicity: nausea, vomiting, loss of appetite, visual disturbances (seeing halos or yellow-green tinge), dizziness, and palpitations.
- Instruct patients to report any of these symptoms to their healthcare provider immediately.
- Advise patients not to stop taking digoxin abruptly without consulting a doctor.
4. Lifestyle and Dietary Advice
- Diet: Encourage a balanced diet rich in potassium (unless contraindicated), especially if the patient is on diuretics. Recommend foods such as bananas, oranges, coconut water, and green leafy vegetables.
- Fluid Intake: Advise on appropriate fluid intake as per the heart failure management plan.
- Avoiding Over-the-Counter Medications: Caution against self-medication with over-the-counter drugs, especially antacids, laxatives, and cold remedies, which may interact with digoxin.
5. Special Considerations for Indian Patients
- Traditional Medicines: Caution patients against using herbal or ayurvedic remedies concurrently with digoxin, as some may affect heart rhythm or interact with the drug.
- Cultural Sensitivity: Use local languages and culturally appropriate examples to ensure comprehension, and involve family members in the education process where appropriate.
6. Follow-Up and Monitoring
- Emphasise the importance of regular follow-up appointments for blood tests (electrolytes, renal function, and digoxin levels) and clinical assessment.
- Encourage patients to maintain a diary of symptoms, pulse rates (if taught self-monitoring), and medication adherence.
Summary Table: Quick Reference for Nurses
| Aspect | Key Points |
| Pre-Administration | Assess pulse, renal function, electrolytes, drug history, allergies |
| During Therapy | Monitor pulse, ECG, electrolytes, signs of toxicity; document findings |
| Managing Toxicity | Withhold drug, inform physician, correct electrolytes, prepare for antidote |
| Patient Education | Purpose of drug, timing, missed dose, toxicity symptoms, diet, follow-up |
Conclusion
Digoxin remains a cornerstone in the management of certain cardiac conditions, but its safe use depends on meticulous nursing assessment, vigilant monitoring, and comprehensive patient education. By integrating these nursing considerations and interventions into daily practice, nurses can significantly reduce the risk of adverse outcomes and empower patients to participate actively in their care. Patient-centred education, especially tailored to local cultural and linguistic needs, further enhances adherence and safety in digoxin therapy.
REFERENCES
- Ernstmeyer K, Christman E, editors. Nursing Pharmacology [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK595000/
- Zhang, C., Xiang, C., Tian, X., Xue, J., He, G., Wu, X., Mei, Z., & Li, T. (2021). Roles of nursing in the management of geriatric cardiovascular diseases. Frontiers in Medicine, 8, 682218. https://doi.org/10.3389/fmed.2021.682218.
- World Health Organization. (2021). Cardiovascular diseases (CVDs). https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)
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