Adult: In 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: 500-1,000 mcg (0.5-1 mg) in divided doses via IV infusion over 10-20 minutes with approx half of the dose given as 1st dose and further fractions of the total dose given every 4-8 hours. Assess clinical response before giving each additional dose. Maintenance: Calculated based on the percentage of the peak body stores lost each day through elimination (refer to individual product guidelines). Most patients with heart failure are maintained on 125-250 mcg (0.125-0.25 mg) daily; a lower dose of ≤62.5 mcg (0.0625 mg) daily may be given to those who show increased sensitivity to the adverse effects while some patients may require a higher dose. Adjust dose based on toxicity, efficacy, and blood levels. Child: Loading dose: Preterm neonates <1.5 kg: 25 mcg/kg over 24 hours; 1.5-2.5 kg: 30 mcg/kg over 24 hours. Term neonates to <5 years 35 mcg/kg over 24 hours; 5-10 years 25 mcg/kg over 24 hours; >10 years Same as adult dose. Loading dose is given in divided doses via IV infusion over 10-20 minutes with approx half of the dose given as 1st dose and further fractions of the total dose given every 4-8 hours. Assess clinical response before giving each additional dose. Maintenance: Preterm neonates 20% of 24-hour loading dose; Term neonates to ≤10 years 25% of 24-hour loading dose; >10 years Same as adult dose. Adjust dose based on toxicity, efficacy, and blood levels. Elderly: Dosage reduction may be needed.
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) as a single dose; or in divided doses 6 hours apart (with approx half the total dose given as the 1st dose) for cases of less urgency or greater risk of toxicity. Assess clinical response before giving each additional dose. Mild heart failure: 250-750 mcg (0.25-0.75 mg) daily for 1 week. Maintenance: Calculated based on the percentage of the peak body stores lost each day through elimination (refer to individual product guidelines). Adjust dose based on toxicity, efficacy, and blood levels. Child: Loading dose: Preterm neonates <1.5 kg: 25 mcg/kg over 24 hours; 1.5-2.5 kg: 30 mcg/kg over 24 hours. Term neonates to <2 years 45 mcg/kg over 24 hours; 2-<5 years 35 mcg/kg over 24 hours; 5-10 years 25 mcg/kg over 24 hours; >10 years Same as adult dose. 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. Assess clinical response before giving each additional dose. Maintenance: Preterm neonates 20% of 24-hour loading dose; Term neonates to ≤10 years 25% of 24-hour loading dose; >10 years Same as adult dose. Adjust dose based on toxicity, efficacy, and blood levels. Elderly: Dosage reduction may be needed.
Renal Impairment
Dosage reduction may be needed.
Administration
May be taken with or without food.
Reconstitution
IV: Administer undiluted or diluted with a 4-fold or greater volume of NaCl 0.9% inj, NaCl 0.18% and glucose 4%, or glucose 5% inj.
Contraindications
Ventricular tachycardia or fibrillation, arrhythmias caused by cardiac glycoside intoxication, supraventricular arrhythmias associated with an accessory atrioventricular pathway (e.g. Wolff-Parkinson-White syndrome); hypertrophic obstructive cardiomyopathy (unless there is concomitant atrial fibrillation and heart failure), intermittent complete heart block or 2nd-degree atrioventricular block (especially if there is a history of Stokes-Adams attacks), constrictive pericarditis (unless it is used to control the ventricular rate in atrial fibrillation or to improve systolic dysfunction).
Special Precautions
Patient with arrhythmias, sinoatrial disorder (e.g. sick sinus syndrome), acute MI, cardiac amyloidosis, myocarditis, beriberi heart disease, severe respiratory disease, hypokalaemia, hypoxia, hypomagnesaemia, marked hypercalcaemia, thyroid disease, hypermetabolic states, malabsorption syndrome (e.g. chronic diarrhoea) or gastrointestinal reconstructions. Patients undergoing elective direct current cardioversion. Renal impairment. Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Arrhythmias, PR interval prolongation, depression of the ST segment on ECG. Blood and lymphatic system disorders: Thrombocytopenia. Cardiac disorders: Conduction disorder, bigeminy, trigeminy, sinus bradycardia. Eye disorders: Visual impairment (e.g. blurred vision, xanthopsia). Gastrointestinal disorders: Diarrhoea, nausea, vomiting, abdominal pain, intestinal ischaemia, gastrointestinal necrosis. General disorders and administration site conditions: Weakness. Nervous system disorders: Dizziness, headache. Psychiatric disorders: Apathy, confusion, mental disturbances (e.g. anxiety, depression, delirium, hallucinations). Reproductive system and breast disorders: Gynaecomastia. Skin and subcutaneous tissue disorders: Rash. Potentially Fatal: Digoxin toxicity.
This drug may cause CNS and visual disturbances, if affected, do not drive or operate machinery.
Monitoring Parameters
Assess serum electrolytes and renal function (serum creatinine concentration) at baseline and periodically. Obtain serum digoxin concentrations just before the next scheduled dose or ≥6 hours after the last dose. Monitor heart rate and rhythm along with periodic ECGs. Observe for signs and symptoms of digoxin toxicity, including noncardiac signs such as confusion and depression.
Overdosage
Symptoms: Almost every type of cardiac arrhythmia and multiple rhythm disturbances, including Mobitz type 1 atrioventricular block, accelerated junctional rhythms, non-paroxysmal atrial tachycardia with atrioventricular block, bi-directional ventricular tachycardia, cardiac arrest from asystole or ventricular fibrillation; hyperkalaemia, nausea, vomiting, anorexia, dizziness, various CNS disturbances, fatigue, malaise, aberration in colour vision (predominance of yellow-green), and weakness. Management: Acute overdose: Administer activated charcoal orally or by nasogastric tube. Life-threatening arrhythmias or hyperkalaemia require administration of digoxin immune Fab; initial treatment with glucose and insulin may be needed if the hyperkalemia is life-threatening. Bradycardia and heart block respond to atropine. A temporary cardiac pacemaker may also be used. Ventricular arrhythmias may respond to lidocaine or phenytoin. Chronic overdose: Place the patient on a cardiac monitor. Correct factors such as electrolyte abnormalities, thyroid dysfunction, and concomitant medications. Correct hypokalaemia by administering K so that serum K is maintained between 4.0 and 5.5 mmol/L; avoid K salts in patients with bradycardia or heart block. Symptomatic arrhythmias may be treated with digoxin immune Fab.
Drug Interactions
Increased effects with loop diuretics, hydrochlorothiazide, amiodarone, canagliflozin, daclatasvir, flibanserin, flecainide, prazosin, propafenone, quinidine, macrolide antibiotics (e.g. erythromycin, clarithromycin, gentamicin), isavuconazole, itraconazole, ivacaftor, quinine, trimethoprim, alprazolam, indometacin, propantheline, mirabegron, nefazodone, atorvastatin, ciclosporin, epoprostenol, vasopressin receptor antagonists (e.g. tolvaptan, conivaptan), carvedilol, ritonavir/ritonavir containing regimens, telaprevir, dronedarone, ranolazine, simeprevir, telmisartan, lapatinib, ticagrelor, vandetanib, velpatasvir, venetoclax and vemurafenib. Concomitant use of sennosides may be associated with a moderate increase in the risk of digoxin toxicity in heart failure patients. Increased risk of hyperkalaemia with suxamethonium. Increased concentrations with lapatinib, NSAIDs, COX-2 inhibitors, verapamil, felodipine, tiapamil, PPIs (e.g. omeprazole). Decreased effects with antacids, certain bulk laxatives, kaolin-pectin, acarbose, neomycin, penicillamine, rifampicin, some cytostatics, metoclopramide, sulfasalazine, epinephrine, salbutamol, colestyramine, phenytoin, bupropion and supplemental enteral nutrition. Potentially Fatal: Agents causing hypokalaemia or intracellular K deficiency (e.g. lithium salts, corticosteroids, carbenoxolone, certain diuretics) may cause increased sensitivity to digoxin. Ca (especially if administered rapidly via IV route) may produce serious arrhythmias in digitalised patients. Concomitant use of digoxin and sympathomimetics may increase the risk of cardiac arrhythmias.
Food Interaction
Decreased peak serum concentrations of digoxin with food. Decreased oral absorption of digoxin with meals containing high fibre (bran) or pectin. Decreased effects with St. John’s wort.
Action
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: Heart rate control: Oral: 1-2 hours (oral); 5-60 minutes (IV). Duration: 3-4 days. Pharmacokinetics: Absorption: Bioavailability: Approx 63% (tab); 75% (oral solution). Time to peak plasma concentration: 2-6 hours (oral); 1-5 hours (IV). Distribution: Extensively distributed to peripheral tissues, with highest concentrations in the heart, liver, kidney, skeletal muscle and intestines. Crosses the placenta and enters breast milk. Plasma protein binding: Approx 25%. Metabolism: Metabolised to active and inactive metabolites, mainly dihydrodigoxin and digoxygenin. Excretion: Mainly via urine (50-70% as unchanged drug). Elimination half-life: 36-48 hours.
Chemical Structure
Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 2724385, Digoxin. https://pubchem.ncbi.nlm.nih.gov/compound/Digoxin. Accessed June 28, 2022.
C01AA05 - digoxin ; Belongs to the class of digitalis glycosides. Used in the treatment of heart failure.
References
Anon. Digoxin. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 10/06/2022.Anon. Digoxin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 10/06/2022.Buckingham R (ed). Digoxin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/06/2022.Digoxin Solution (Amici Pharmaceuticals, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 10/06/2022.Digoxin Tablets BP 0.25 mg (Bristol Laboratories Ltd). MHRA. https://products.mhra.gov.uk. Accessed 10/06/2022.Joint Formulary Committee. Digoxin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/06/2022.Lanoxin Injection (Aspen Bad Oldesloe GmbH). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 10/06/2022.Lanoxin Injection (Aspen Pharma Trading Limited). MHRA. https://products.mhra.gov.uk. Accessed 10/06/2022.Lanoxin Injection, Solution (Covis Pharma US, Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 10/06/2022.Lanoxin PG Elixir (Aspen Bad Oldesloe GmbH). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 10/06/2022.Lanoxin PG Elixir (Aspen Pharma Trading Limited). MHRA. https://products.mhra.gov.uk. Accessed 10/06/2022.Lanoxin Tablet (Concordia Pharmaceuticals Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 10/06/2022.Lanoxin Tablets (Aspen Bad Oldesloe GmbH). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 10/06/2022.Pharmacy Retailing NZ Limited. Digoxin Tablets 62.5 mcg (0.0625 mg) and 250 mcg (0.250 mg); Paediatric Elixir 50mcg/mL data sheet November 2019. Medsafe. http://www.medsafe.govt.nz. Accessed 10/06/2022.
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