Digoxin is indicated in:
- Heart failure
- Atrial fibrillation with an uncontrolled ventricular rate
- Acute left ventricular failure
- Chronic left ventricular failure and congestive heart failure, especially when caused by hypertensive valvular (especially mitral valvular) disease or ischaemic heart disease.
Positive Inotropic drugs
Digoxin is a cardiac glycoside used in the management of particularly atrial fibrillation and in heart failure. The principal actions of digoxin are an increase in the force of myocardial contraction (positive inotropic activity) and a reduction in the conductivity of the heart particularly in conduction through the atrioventricular (AV) +node. Digoxin also has a direct action on vascular smooth muscle and indirect effects mediated primarily by the autonomic nervous system and particularly by an increase in the vagal activity.
Dosage & Administration
For rapid action: 1 to 1.5 mg in divided doses over 24 hours
For less urgent digitalisation: 0.25 to 0.5 mg daily(higher dose may be divided); Maintenance: 0.0625 to 0.5 mg daily (higher dose may be divided) accordingly to renal function and in atrial fibrilation on heart rate response;
Usual dose: 0.125 to 0.25 mg daily (lower dose my be appropriate in elderly).
Effectiveness reduced by phenytoin, neomycin, sulphasalazine, kaolin, pectin, antacids and in patients receiving radiotherapy. Metoclopramide may alter the absorption of solid dosage forms of digoxin. Blood levels increased by calcium channel blockers, spironolactone, quinidine and calcium salts.
Potentially Fatal: Electrolyte imbalances such as hypokalaemia and hypomagnesemia (e.g. admin of potassium-losing diuretics, corticosteroids) can increase the risk of cardiac toxicity.
Ventricular fibrillation and hypersensitivity to digoxin or other digitalis preparation.
Usually associated with excessive dosage include anorexia, nausea, vomiting, diarrhoea, abdominal pain, visual disturbance, headache, fatigue, drowsiness, confusion, delirium, hallucination, depression, arrhythmia, heart block, intestinal ischaemia, gynaecomastia on long term use, thrombocytopenia reported.
Pregnancy & Lactation
Use in pregnancy: Digoxin can be used.
Use in lactation: Digoxin is excreted in breast milk but in concentration below those found in plasma and therefore poses no hazard to the breast-feed infant.
Cardiac dysrhythmias, hypokalaemia, hypertension, IHD, hypercalcaemia, hypomagnesaemia, electroconversion, chronic cor pulmonale, aortic valve disease, acute myocarditis, congestive cardiomyopathies, constrictive pericarditis, heart block, elderly, renal impairment, abnormalities in thyroid function; pregnancy. IV digoxin can only be given to patients who have not received cardiac glycosides in the preceding 2 wk.
Symptoms: Hyperkalaemia, cardiac arrhythmias and heart block.
Management: Treatment is symptomatic and supportive. Reduce absorption by gastric lavage if present within 30 min of ingestion. Do not induce vomiting or attempt passage of a gastric tube if presented >2 hr after ingestion or already has toxic manifestations, as this may induce an acute vagal episode and worsen digitalis-related arrhythmias. Activated charcoal is helpful in reducing drug absorption.
Use in Special Population
Use in children & neonates: Digoxin can be used.
Use in elderly: Partly because of reduced renal function and partly because of their tissues are more sensitive to the effects of digitalis, the elderly require lower maintenance dose of digoxin than younger adults
Store at 25°C.