Digoxin

What is the use of Digoxin and how it works?

It has direct effects on myocardial contractility and electrophysiological conduction properties i.e. 1. Negative chronotropic effect (reduces heart rate & A.V. conduction). 2. Positive inotropic effect i.e. there is a dose dependent increase in force of contraction of myocardium. The above two effects thereby make it an ideal drug for treatment of cardiac failure of diverse etiologies without increasing the oxygen demand of the failing myocardium. There is also a mild direct vasoconstrictor action thereby increasing peripheral resistance mildly. Diuresis is seen promptly in CHF patients owing to improved renal perfusion which was previously comprised but at times an addition of diuretic may be considered to improve the patients hypoxic and hypervolemic condition rapidly if need arises.

Indications of Digoxin

Congestive heart failure, cardiac tachyarrhythmias (Paroxysmal supraventricular tachycardia, atrial flutter and fibrillation).

Dosage of Digoxin

Initially 0.25-1.5 mg daily. Maint; 0.25-0.5 mg daily. Children: initially 10-20 mcg/kg body weight 6 hourly. Maint 10-20 mcg/kg body weight in single or divided doses daily.

Contracdictions of Digoxin

Hypokalemia, ventricular tachycardia, partial A.V. block, acute myocarditis. Wolf-Parkinson-White Syndrome.

Precautions of Digoxin

Elderly, renal or severe hepatic disease, myocardial infarction, thyrotoxicosis, calcium synergizes to precipitate toxicity.

Pediatrics: Reduces doses necessarily.

Pregnancy: No evidence of risk.

Lactation: Present in breast milk hence use only if indicated.

Drug Interactions of Digoxin

Diuretics causes hypokalemia and precipitate digitalis toxicity. Blood levels increased by calcium channel blockers, spironolactone, quinidine and calcium salts. Metaclopromide interferes with absorption of solid dosage form of digoxin. Antacids reduces digxin absorption.

Side effects of Digoxin

Anorexia, nausea, vomiting, abdominal pain, fatigue, headache, mental confusion, restlessness.

Drug A-Z Index

Digoxin
Propranolol
Metaprolol
Atenolol