Dosage / Direction for Use
Oral Adult & childn >10 yr Rapid oral loading dose 750-1,500 mcg as a single dose. Slow oral loading dose 250-750 mcg daily for 1 wk followed by an appropriate maintenance dose. Maintenance dose: Usually 125-250 mcg/day or ≤62.5 mcg/day may suffice. Oral loading dose Childn 5-10 yr 25 mcg/kg, 2-5 yr 35 mcg/kg. Term neonate to 2 yr 45 mcg/kg, preterm neonate 1.5-2.5 kg 30 mcg/kg, preterm neonate <1.5 kg 25 mcg/kg. Doses taken per 24 hr. Inj 500-1,000 mcg loading dose, depending on age, lean body wt & renal function. IV loading dose Childn 5-10 yr 25 mcg/kg, 2-5 yr 35 mcg/kg. Term neonate to 2 yr 35 mcg/kg, preterm neonate 1.5-2.5 kg 30 mcg/kg, preterm neonate <1.5 kg 20 mcg/kg. Doses taken over 24 hr. Loading doses administered in divided doses w/ ½ the total dose given as the 1st dose & the remainder given at 4-8-hrly intervals, assessing clinical response before giving each additional dose.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity to other digitalis glycosides. Intermittent complete heart block or 2nd-degree AV block esp if there is a history of Stokes-Adams attacks; arrhythmia caused by cardiac glycoside intoxication, supraventricular arrhythmia caused by Wolff-Parkinson-White syndrome; ventricular tachycardia or fibrillation; hypertrophic obstructive cardiomyopathy.
Special Precautions
Sick sinus syndrome; acute myocarditis; renal failure (decrease dose & monitor closely); hypokalemia; hypoxia; hypercalcemia; hypomagnesemia; thyroid dysfunction; severe resp distress; w/hold Lanoxin for 24 hr before electroconversion. Avoid IM route of administration. Malabsorption syndrome or GI reconstructions. Patients w/ heart failure associated w/ cardiac amyloidosis. Patients w/ severe resp disease. May impair the ability to drive or operate machinery. Pregnancy. Elderly.
Side Effects / Adverse Reactions
CNS disturbances, dizziness; visual disturbances (blurred or yellowish vision); arrhythmia, conduction disturbances, bigeminy, trigeminy, PR prolongation, sinus bradycardia; nausea, vomiting, diarrhea; urticarial or scarlatiniform w/ eosinophilia.
Interactions
Sensitivity is increased w/ agents causing hypokalemia eg diuretics, lithium salts, carbenoxolone, corticosteroids; Ca. Digoxin levels increased by: Amiodarone, flecainide, prazosin, propafenone, quinidine, spironolactone, erythromycin, clarithromycin, tetracycline, gentamicin, itraconazole, quinine, trimethoprim, alprazolam, indomethacin, propantheline, nefazodone, atorvastatin, cyclosporine, epoprostenol, carvedilol. Digoxin levels reduced by: Antacids, some bulk laxatives, kaolin-pectin, acarbose, neomycin, penicillamine, rifampicin, some cytostatics, metoclopramide, sulphasalazine, adrenaline, salbutamol, cholestyramine, phenytoin, St. John's wort (Hypericum perforatum). Verapamil, felodipine & tiapamil.