DIGOXIN PEDIATRIC
Clinical safety rating: safe
Animal studies have demonstrated safety
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.
| 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. |
| Molecular Weight | 780.95 |
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. |
| 1st trimester | Use only if potential benefit justifies risk; may be associated with increased risk of fetal death or spontaneous abortion if mother is toxic. |
| 2nd trimester | Use only if clearly needed; monitor maternal serum levels and fetal heart rate. |
| 3rd trimester | Use only if clearly needed; monitor for fetal effects (e.g., bradycardia) and avoid maternal toxicity. |
Clinical note
Many drugs can increase levels (eg amiodarone verapamil) causing toxicity Can cause life-threatening arrhythmias due to its narrow therapeutic index.
| Placental transfer | Crosses the placenta; fetal serum concentrations approximate maternal levels. |
| Breastfeeding | Digoxin is excreted into breast milk in very low concentrations (estimated infant dose about 1-3% of maternal weight-adjusted dose). Considered compatible with breastfeeding; however, monitor infant for signs of digitalis toxicity such as vomiting, diarrhea, or bradycardia. |
■ FDA Black Box Warning
Toxicity can be life-threatening. Use caution in renal impairment, electrolyte disturbances (hypokalemia, hypomagnesemia, hypercalcemia). Narrow therapeutic index requires monitoring.
| Common Effects | atrial fibrillation |
| Serious Effects |
Hypersensitivity to digoxin or other digitalis glycosidesVentricular fibrillationAV block (second or third degree) unless pacemaker presentWolff-Parkinson-White syndrome with atrial fibrillationIdiopathic hypertrophic subaortic stenosis (IHSS)
| 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. |
| Food/Dietary |
Loading safety data…
| Geriatric use | Not applicable for pediatric formulation. For elderly, use adult digoxin dosing with caution: reduced renal function may require lower maintenance doses. Typical adult maintenance: 0.0625-0.25 mg daily based on renal function and lean body mass. |
| Lactation Rating | L2 (Safer) |
| 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. |
| Fetal Monitoring | Monitor maternal serum digoxin levels (target 0.5–2 ng/mL for heart failure, 0.8–2 ng/mL for arrhythmias). Assess maternal heart rate and ECG for toxicity (bradycardia, arrhythmias). Fetal monitoring: fetal heart rate auscultation or ultrasound for bradycardia or arrhythmias. Therapeutic drug monitoring recommended during pregnancy. |
| Fertility Effects | No direct adverse effects on fertility reported in animal or human studies. Underlying cardiac condition may impact pregnancy planning. |
| High-fiber foods may decrease absorption; take digoxin 1 hour before or 2 hours after meals. Avoid natural licorice, which can cause hypokalemia and increase toxicity. Maintain consistent dietary potassium intake. |
| Clinical Pearls | Monitor serum digoxin levels (therapeutic range 0.5-2 ng/mL) and renal function, especially in neonates. Correct hypokalemia, hypomagnesemia, and hypercalcemia before administration to reduce toxicity risk. Use with caution in patients with WPW, hypertrophic cardiomyopathy, or incomplete heart block. Dosing in infants and children is based on weight and renal function. |
| Patient Advice | Take exactly as prescribed; do not double up doses. · Monitor for signs of toxicity: nausea, vomiting, vision changes (yellow-green halos), arrhythmias. · Keep medication out of reach of children; immediate medical attention if overdose suspected. · Do not stop abruptly without consulting healthcare provider. · Inform healthcare provider of all medications, including OTC and herbal supplements. |