BNF for Children 2011-2012

74 2.1.1 Cardiac glycosides BNFC 2011–20122 Cardiovascular systemresponse in persistent atrial fibrillation (section 2.3.1).Digoxin has a limited role in children with chronic heartfailure; for reference to the role of digoxin in heartfailure, see section 2.2.For the management of atrial fibrillation, the maintenancedose of digoxin is determined on the basis of theventricular rate at rest, which should not be allowed tofall below an acceptable level for the child.Digoxin is now rarely used for rapid control of heart rate(see section 2.3.2), even with intravenous administration,response may take many hours; persistence oftachycardia is therefore not an indication for exceedingthe recommended dose. The intramuscular route is notrecommended.In children with heart failure who are in sinus rhythm, aloading dose may not be required.Unwanted effects depend both on the concentration ofdigoxin in the plasma and on the sensitivity of theconducting system or of the myocardium, which isoften increased in heart disease. It can sometimes bedifficult to distinguish between toxic effects and clinicaldeterioration because the symptoms of both are similar.The plasma-digoxin concentration alone cannot indicatetoxicity reliably, but the likelihood of toxicityincreases progressively through the range 1.5 to 3 micrograms/litrefor digoxin. Renal function is very importantin determining digoxin dosage.Hypokalaemia predisposes the child to digitalis toxicityand should be avoided; it is managed by giving a potassium-sparingdiuretic or, if necessary, potassium supplements.If toxicity occurs, digoxin should be withdrawn; seriousmanifestations require urgent specialist management.Digoxin-specific antibody fragments are available forreversal of life-threatening overdosage (see below).DIGOXINCautions sick sinus syndrome; thyroid disease;hypoxia; severe respiratory disease; avoid hypokalaemia,hypomagnesaemia, hypercalcaemia, andhypoxia (risk of digitalis toxicity); monitor serumelectrolytes and renal function; avoid rapid intravenousadministration (risk of hypertension andreduced coronary flow); interactions: Appendix 1(cardiac glycosides)Contra-indications intermittent complete heart block,second degree AV block; supraventricular arrhythmiasassociated with accessory conducting pathwayse.g. Wolff-Parkinson-White syndrome (although canbe used in infancy); ventricular tachycardia or fibrillation;hypertrophic cardiomyopathy (unless concomitantatrial fibrillation and heart failure—but usewith caution); myocarditis; constrictive pericarditis(unless to control atrial fibrillation or improve systolicdysfunction—but use with caution)Renal impairment use half normal dose if estimatedglomerular filtration rate is 10–50 mL/minute/1.73 m 2 and use a quarter normal dose if estimatedglomerular filtration rate is less than 10 mL/minute/1.73 m 2 ; monitor plasma-digoxin concentration; toxicityincreased by electrolyte disturbancesPregnancy may need dosage adjustmentBreast-feeding amount too small to be harmfulSide-effects see notes above; also nausea, vomiting,diarrhoea; arrhythmias, conduction disturbances;dizziness; blurred or yellow vision; rash, eosinophilia;less commonly depression; very rarely anorexia,intestinal ischaemia and necrosis, psychosis, apathy,confusion, headache, fatigue, weakness, gynaecomastiaon long-term use, and thrombocytopeniaPharmacokinetics For plasma-digoxin concentrationassay, blood should be taken at least 6 hoursafter a dose; plasma-digoxin concentration shouldbe maintained in the range 0.8–2 micrograms/litre(see also notes above)Licensed use heart failure, supraventricular arrhythmiasIndication and doseSupraventricular arrhythmias and chronic heartfailure (see also notes above) consult productliterature for details. By mouthNeonate under 1.5 kg initially 25 micrograms/kgin 3 divided doses for 24 hours then 4–6 micrograms/kgdaily in 1–2 divided dosesNeonate 1.5–2.5 kg initially 30 micrograms/kg in3 divided doses for 24 hours then 4–6 micrograms/kg daily in 1–2 divided dosesNeonate over 2.5 kg initially 45 micrograms/kg in3 divided doses for 24 hours then 10 micrograms/kg daily in 1–2 divided dosesChild 1 month–2 years initially 45 micrograms/kg in 3 divided doses for 24 hours then 10 micrograms/kgdaily in 1–2 divided dosesChild 2–5 years initially 35 micrograms/kg in 3divided doses for 24 hours then 10 micrograms/kgdaily in 1–2 divided dosesChild 5–10 years initially 25 micrograms/kg(max. 750 micrograms) in 3 divided doses for 24hours then 6 micrograms/kg daily (max.250 micrograms daily) in 1–2 divided dosesChild 10–18 years initially 0.75–1.5 mg in 3divided doses for 24 hours then 62.5–250 microgramsdaily in 1–2 divided doses (higher dosesmay be necessary). By intravenous infusion (but rarely necessary)Neonate under 1.5 kg initially 20 micrograms/kgin 3 divided doses for 24 hours then 4–6 micrograms/kgdaily in 1–2 divided dosesNeonate 1.5–2.5 kg initially 30 micrograms/kg in3 divided doses for 24 hours then 4–6 micrograms/kg daily in 1–2 divided dosesNeonate over 2.5 kg initially 35 micrograms/kg in3 divided doses for 24 hours then 10 micrograms/kg daily in 1–2 divided dosesChild 1 month–2 years initially 35 micrograms/kg in 3 divided doses for 24 hours then 10 micrograms/kgdaily in 1–2 divided dosesChild 2–5 years initially 35 micrograms/kg in 3divided doses for 24 hours then 10 micrograms/kgdaily in 1–2 divided dosesChild 5–10 years initially 25 micrograms/kg(max. 500 micrograms) in 3 divided doses for 24hours then 6 micrograms/kg daily (max.250 micrograms daily) in 1–2 divided doses