Adult: For patients who have not received cardiac glycosides in the previous 2 weeks. Dosage is individualised according to age, lean body weight and renal status. Loading dose of 500-1,000 mcg (0.5-1 mg) by IV infusion over a period of 10-20 minutes in divided doses with approx half of the dose given as first dose and further fractions of the total dose given every 4-8 hours. Child: Loading dose: Preterm neonates <1.5 kg: 25 mcg/kg/day;1.5-2.5 kg: 30 mcg/kg/day. Term neonates-2 years 45 mcg/kg/day; >2-5 years 35 mcg/kg/day; >5-10 years 25 mcg/kg/day. Maintenance: Preterm neonates 20% of 24-hour loading dose; Term neonates and children up to 10 years 25% of 24-hour loading dose. Elderly: Dosage reductions may be needed.
Oral Heart failure, Supraventricular arrhythmias
Adult: Dosage is individualised according to age, lean body weight and renal status. Rapid digitalisation: Loading dose of 750-1,500 mcg (0.75-1.5 mg) during the first 24-hour period as a single dose; or in divided doses every 6 hours for less urgent or greater risk cases. For mild heart failure (loading dose may not be required): 250-750 mcg (0.25-0.75 mg) daily for 1 week. Maintenance: Individualised based on the percentage of the peak body stores lost each day. Usual maintenance: 125-250 mcg daily but may range from 62.5-500 mcg daily. Child: Loading dose: Preterm neonates <1.5 kg: 25 mcg/kg/day; 1.5-2.5 kg: 30 mcg/kg/day. Term neonates to 2 years 45 mcg/kg/day; >2-5 years 35 mcg/kg/day; >5-10 years 25 mcg/kg/day. Loading dose is given in divided doses with approx half the total dose given as the 1st dose and further fractions of the total dose given at intervals of 4-8 hours. Maintenance: Preterm neonates 20% of 24-hour loading dose; Term neonates and children up to 10 years 25% of 24-hour loading dose. Elderly: Dosage reductions may be needed.
Dosage reductions may be needed.
May be taken with or without food.
IV inj: Administer undiluted or diluted with a 4-fold or greater volume of sterile water for inj, NaCl 0.9% inj, or dextrose 5% inj.
Ventricular tachycardia/fibrillation, hypertrophic obstructive cardiomyopathy, cardiac amyloidosis, constrictive pericarditis. Arrhythmias due to cardiac glycoside intoxication or accessory AV pathways (e.g. Wolff-Parkinson-White syndrome). Intermittent complete heart block or 2nd-degree AV block (especially if there is history of Stokes-Adams attacks).
Patients with acute MI, heart failure, arrythmias, sinoatrial disorder, beri-beri heart disease, electrolyte imbalance (especially hypokalaemia, hypomagnesaemia, hypercalcaemia), thyroid disease, severe respiratory disease, sick sinus syndrome, malabsorption syndrome, gastrointestinal reconstructions. Renal impairment. Elderly and children. Pregnancy and lactation.
This drug may cause visual disturbances, if affected, do not drive or operate machinery.
Periodical tests for serum electrolytes and serum creatinine concentration. Heart rate and rhythm should be monitored along with periodic ECGs. Observe for noncardiac signs of toxicity such as confusion and depression.
Symptoms: Gastrointestinal effects are often the first sign of toxicity which include anorexia, nausea, vomiting, diarrhoea, abdominal pain, and bloating. Cardiac manifestations including palpitations, syncope, multiple rhythm disturbance, prolongation of the PR interval, AV conduction disturbance or sinus bradycardia, and ventricular arrhythmias. Neurologic and visual effects (e.g. dizziness, fatigue, malaise, weakness, drowsiness, behavioural disturbance, and aberration of colour vision) may also occur. Management: Gastric lavage is rarely performed, consider pre-treatment with atropine. In acute poisoning, large doses of activated charcoal prevent further absorption of digoxin and decrease serum levels by intestinal binding of digoxin. If hypokalaemia is present, oral or IV K supplements are given. Digoxin-specific antibody Fab is a specific treatment for digoxin toxicity and is very effective.
ACE inhibitors (e.g. captopril), angiotensin receptor blockers (e.g. telmisartan), NSAIDs (e.g. indomethacin), COX-2 inhibitors, calcium channel blockers (e.g. verapamil, felodipine, tinapamil), antiarrhythmics (e.g. amiodarone, flecainide) antibiotics (e.g. erythromycin, tetracyclines), vasopressin receptor antagonist (tolvaptan, conivaptan), itraconazole, quinine, alprazolam, propantheline, nefazodone, atorvastatin, ciclosporin, epoprostenol, ritonavir, telaprevir, ranolazine, lapatinib, ticagrelor may increase digoxin levels. Antacids, bulk-laxatives, kaolin-pectin, acarbose, neomycin, penicillamine, rifampicin, some cytostatics, metoclopramide, sulfasalazine, adrenaline, salbutamol, cholestyramine, phenytoin, St. John’s wort, bupropion, and supplemental enteral nutrient may decrease digoxin levels. Potentially Fatal: May increase AV conduction time with beta-adrenoceptor blocking drugs. Drugs that may cause hypokalaemia such as lithium salts, corticosteroids, carbenoxolone and diuretics (e.g. loop or hydrochlorothiazide) may increase sensitivity to digoxin. May worsen cardiac arrythmias and hypokalaemia with sympathomimetics (e.g. epinephrine, norepinephrine, dopamine). May cause sudden extrusion of K from muscle cells causing arrhythmias with neuromuscular blocking agents (e.g. succinylcholine). Rapid IV injection of Ca may produce serious arrhythmias in digitalised patients.
Decreased peak serum concentrations of digoxin with food. Decreased oral absorption of digoxin with meals containing high fibre (bran) or pectin.
Description: Digoxin is a cardiac glycoside which has positive inotropic activity characterised by an increase in the force of myocardial contraction. It also reduces the conductivity of the heart through the atrioventricular (AV) node. Digoxin also exerts direct action on vascular smooth muscle and indirect effects mediated primarily by the autonomic nervous system and an increase in vagal activity. Onset: 1-2 hours (oral); 5-60 minutes (IV). Duration: 3-4 days. Pharmacokinetics: Absorption: Absorption from gastrointestinal tract is variable. Bioavailability: 63% (as tablet); 75% (as oral solution). Time to peak plasma concentration: 2-6 hours (oral); 1-5 hours (IV). Distribution: Widely distributed in tissues. Crosses the placenta and enters the breast milk. Volume of distribution: 7 L/kg. Plasma protein binding: Approx 25%. Metabolism: Metabolised to active and inactive metabolites, mainly dihydrodigoxin and digoxygenin. Excretion: Via urine (50-70% as unchanged drug). Elimination half-life: 36-48 hours.
C01AA05 - digoxin ; Belongs to the class of digitalis glycosides. Used in the treatment of heart failure.
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