DIGOXIN PEDIATRIC

Clinical safety rating: safe

Animal studies have demonstrated safety

How it works

Inhibits sodium-potassium ATPase, increasing intracellular sodium, which promotes calcium influx via sodium-calcium exchanger, enhancing cardiac contractility. Also increases vagal tone, slowing AV conduction.

What the body does with it

Metabolism	Primarily renally excreted unchanged; minimal hepatic metabolism (mostly via reduction, hydrolysis, and conjugation in older children).
Excretion	Renal excretion accounts for 50-70% of elimination as unchanged drug; biliary/fecal excretion accounts for 30-40%, primarily as metabolites; enterohepatic recirculation occurs.
Half-life	Terminal elimination half-life in neonates is 35-70 hours, infants 18-30 hours, children 12-30 hours, and adults 36-48 hours; prolonged in renal impairment and hypothyroidism.
Protein binding	25% bound to serum albumin; binding decreases in uremia and hyperbilirubinemia.
Volume of Distribution	Vd: 6-10 L/kg in infants and children, 5-7 L/kg in adults; large Vd indicates extensive tissue binding, particularly to cardiac muscle (Na+/K+-ATPase).
Bioavailability	Oral: 60-80% (elixir 70-85%, tablets 60-75%); IM: 70-85% (but erratic absorption and pain limit use); IV: 100%.
Onset of Action	Oral: 0.5-2 hours; IV: 5-30 minutes; peak effect oral 2-6 hours, IV 1-4 hours.
Duration of Action	Effect persists for 3-7 days due to slow tissue distribution; clinical effects (inotropic) last 1-2 days after dose adjustment, but electrophysiologic effects (e.g., AV node blockade) persist longer.

Classification & Brands

Dosing & administration

For pediatric patients, digoxin pediatric dosing is weight-based; no standard adult dose. Typical pediatric loading dose: 10-12 mcg/kg orally divided every 6-8 hours, with maintenance: 5-10 mcg/kg/day divided every 12 hours. For infants <1 month, loading: 10-15 mcg/kg, maintenance: 4-6 mcg/kg/day. For children 1-24 months, loading: 15-20 mcg/kg, maintenance: 5-8 mcg/kg/day. For children >2 years, loading: 10-15 mcg/kg, maintenance: 3-5 mcg/kg/day.

Dosage form	INJECTABLE
Renal impairment	Digoxin is primarily renally excreted. For pediatric patients, if GFR <30 mL/min/1.73m2, reduce maintenance dose by 50% and monitor serum levels. For GFR 30-60, reduce dose by 25-50%. In neonates with renal impairment, dose reduction proportional to creatinine clearance.
Liver impairment	Digoxin is minimally hepatically metabolized; no dose adjustment required for hepatic impairment. However, in Child-Pugh class C, monitor levels due to potential altered distribution.
Pediatric use	See standard_dosing. Weight-based dosing: total digitalizing dose (TDD) and maintenance as above. For premature infants, TDD 10-15 mcg/kg, maintenance 3-5 mcg/kg/day divided q12h. For full term neonates, TDD 15-20 mcg/kg, maintenance 5-7 mcg/kg/day. For infants 1-24 months, TDD 20-25 mcg/kg, maintenance 7-10 mcg/kg/day. For children 2-10 years, TDD 10-15 mcg/kg, maintenance 5-7 mcg/kg/day. For children >10 years, TDD 10-15 mcg/kg, maintenance 3-5 mcg/kg/day. Divide TDD into 3-4 doses every 6-8 hours. Maintenance started 12 hours after last loading dose.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Many drugs can increase levels (eg amiodarone verapamil) causing toxicity Can cause life-threatening arrhythmias due to its narrow therapeutic index.

Breastfeeding	Digoxin is excreted into breast milk in low concentrations. M/P ratio approximately 0.6–0.9. Infant dose via milk is <1% of maternal weight-adjusted dose, unlikely to cause adverse effects in term infants. Caution in preterm or neonates with renal impairment.
Teratogenic Risk	Digoxin crosses the placenta. First trimester: No increased risk of major malformations reported in human studies. Second/third trimester: Potential for fetal toxicity (e.g., bradycardia, cardiac arrhythmias) at maternal toxic doses. No known teratogenicity at therapeutic doses.

Warnings & precautions

■ FDA Black Box Warning

Toxicity can be life-threatening. Use caution in renal impairment, electrolyte disturbances (hypokalemia, hypomagnesemia, hypercalcemia). Narrow therapeutic index requires monitoring.

Side Effect Profile

Common Effects	atrial fibrillation
Serious Effects

Absolute Contraindications

Ventricular fibrillation, hypersensitivity to digitalis preparations, hypokalemia (uncorrected), hypercalcemia (uncorrected), AV block (second or third degree) unless pacemaker present.

Clinical Precautions

Precautions

Monitor serum digoxin levels, renal function, electrolytes (potassium, magnesium, calcium). Risk of arrhythmias (including ventricular fibrillation, bradycardia, AV block). Use with caution in patients with thyroid disease, acute myocardial infarction, or myocarditis.

Clinical Tips & Counseling

Drug interactions

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