Digoxin
Cardiac Therapy · Cardiac glycoside
Indications
Digitalis therapy, particularly congestive heart failure.
Dosage
ORAL: Rapid digitalisation, Adults: 1-1.5 mg in divided doses over 24 hr; less urgent digitalisation, Adults: 250-500 mcg daily (higher dose may be divided). Maintenance, 62.5-500 mcg daily (higher dose may be divided) according to renal function and, in atrial fibrillation, on heart-rate response; usual range, 125-250 mcg daily (lower dose may be appropriate in elderly). INJECTION: Adults: Emergency loading dose by IV infusion, 0.75-1 mg over at least 2 hr, then maintenance dose by mouth on the following day. Children: Digitalizing Dose: Premature Infants: 20-30 mcg/kg orally or 15-25 mcg/kg IV. Full-Term Infants: 25-35 mcg/kg orally or 20-30 mcg/kg IV. 1-24 mth: 35-60 mcg/kg orally or 30-50 mcg/kg IV. 2-5 yr age: 30-40 mcg/kg orally or 25-35 mcg/kg IV. 5-10 yr age: 20-35 mcg/kg orally or 15-30 mcg/kg IV. Above 10 yr age: 10-15 mcg/kg orally or 8-12 mcg/kg IV. Maintenance: Premature…
Administration
Administer by direct IV inj slowly over a period of 5 min or longer, given undiluted or diluted with a fourfold or greater volume of SWFI, D5W or NS. Compatibility: Stable in D5 ½ NS, with KCl 20 mEq, D5W, D10W, LR, 1/2NS, NS and SWFI (when diluted fourfold or greater). Y-site administration: Drug to Drug IV Compatibility: Cimetidine, ciprofloxacin, cisatracurium, diltiazem, esmolol, famotidine, fentanyl, heparin, insulin regular, linezolid, meropenem, midazolam, milrinone, morphine, ranitidine. Drug to Drug IV Incompatibility: Amiodarone, amphotericin B cholesteryl sulphate complex, dobutamine, fluconazole, foscarnet, propofol. In syringe: Incompatible with doxapram. When admixed: Incompatible with dobutamine. Stability: Store at 25°C (77°F); excursions are permitted between 15°C-30°C (59°F-86°F). Protect from light.
Adverse Effects
Usually associated with excessive dosage, include; anorexia, nausea, vomiting, diarrhoea, abdominal pain; visual disturbances, CNS disturbances, headache, fatigue, drowsiness, confusion, delirium, hallucinations, depression, arrhythmias, heart block, PR prolongation, sinus bradycardia, rarely rash, intestinal ischaemia, gynaecomastia on long-term use; thrombocytopenia reported.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: Intermittent complete heart block, second degree AV block; supra-ventricular arrhythmias caused by Wolff-Parkinson-White syndrome; hypertrophic obstructive cardiomyopathy (unless concomitant atrial fibrillation and heart failure but with caution), ventricular tachycardia, ventricular fibrillation. Elective electro-conversion. Precautions: AV block, acute MI, cardiac amyloidosis, constrictive pericarditis, beriberi heart disease, myocarditis, cation imbalance, hypercalcaemia, hypokalaemia, hypomagnesaemia, hypoxia, severe pulmonary disease, thyroid dysfunction, renal insufficiency, malabsorption. Monitor serum electrolytes and renal function periodically. Elderly.
Interactions
Diuretics, lithium, corticosteroids, carbenoxolone, lithium, other K+ depleting agents, alprazolam, amiodarone, gentamicin, indomethacin, itraconazole, captopril, verapamil, felodipine, tiapamil, flecainide, prazosin, propafenone, quinidine, quinine, beta-blockers, suxamethonium, spironolactone, tetracycline, erythromycin, trimethoprim, propantheline, adrenaline, antacids, kaolin, pectin, laxatives, cholestyramine, acarbose, salbutamol, diphenoxylate, sulphasalazine, neomycin, rifampicin, cytostatics, phenytoin, metoclopramide, penicillamine, calcium inj or supplement, other cardiac glycosides, St. John's Wort, vit D analogues, bupropion.
Advice to Patient
Take oral forms with or without meals. Take digoxin at same time each day to help increase compliance. Maintain sufficient dietary intake of potassium. Contact prescriber if there is loss of appetite, nausea, vomiting, swelling of extremities, persistent diarrhoea, abdominal discomfort, palpitations, blurred vision, yellowing of eyes, mental confusion, depression or unusual fatigue. Take pulse at the same time each day. Inform prescriber if pulse falls below 60 beats per minute or suddenly increases. Do not carry digoxin in anything other than its original labelled container. Use special dropper supplied with elixir to ensure accurate dose measurement. Take missed dose as soon as you remember within 12 hours of scheduled dose. Carry medical identification card that indicates need for digoxin.
Pharmacokinetics
Onset of action: Heart rate control: Oral: 1-2 hrs. IV: 5-60 min. Peak effect: Heart rate control: Oral: 2-8 hrs. IV: 1-6 hrs. Duration: Adults: 3-4 days. Absorption: By passive non saturable diffusion in the upper small intestine; food may delay, but does not affect extent of absorption. Metabolism: Via sequential sugar hydrolysis in the stomach or by reduction of lactone ring by intestinal bacteria. Bioavailability: Oral (formulation dependent): Elixir: 70%-85%. Tab: 60%-80%. Half-life elimination (age, renal & cardiac function dependant): Neonates: Premature: 61-170 hrs. Full-term: 35-45 hrs. Infants: 18-25 hrs. Children: 18-36 hrs. Adults: 36-48 hrs. Adults, anephric: 3.5-5 days. Half-life elimination: Parent drug: 38 hrs. Metabolites: Digoxigenin: 4 hrs. Monodigitoxoside: 3-12 hrs. Time to peak, serum: Oral: 1-3 hrs. Excretion: Urine.
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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