Digitoxin (Crystodigin)

Category:

  • Cardiac

Description:

  • Antidysrhythmic; cardiac glycoside

Indications:

  • Congestive heart failure, atrial fibrillation, atrial flutter

  • Paroxysmal atrial tachycardia (PAT)

  • Cardiogenic shock

Contraindications:

  • Ventricular tachycardia

  • Ventricular fibrillation

Precautions:

  • Pregnancy category C; passes readily into fetus; excretion into breast milk unknown

  • Hypokalemia, hypomagnesemia, hypercalcemia, hypothyroidism, sick sinus syndrome

  • Severe pulmonary disease, hepatic disease, AV block, acute MI, hepatic disease

  • Wolff-Parkinson-White syndrome

Adverse Reactions (Side Effects):

  • CNS: anorexia, apathy, confusion, delirium, disorientation, drowsiness, EEG abnormalities, hallucinations, headache, mental depression, neuralgia, psychosis, restlessness, seizures, weakness

  • CV: atrial fibrillation, AV block, bradycardia, premature ventricular contractions (PVCs), ventricular fibrillation, ventricular tachycardia

  • EENT: visual disturbances (blurred, yellow or green halo effect)

  • GI: abdominal discomfort, diarrhea, hemorrhagic necrosis of the intestines, nausea, vomiting

  • HEME: eosinophilia, thrombocytopenia

  • SKIN: rash

Dosage:

Administered orally (tablet)

  • Adult:            Loading dose PO (rapid) 0.6mg, followed by 0.4mg, then 0.2mg at every 4-6 hour intervals; (slow) 0.2mg 2 times daily for 4 days; maintenance dose PO 0.05-0.3mg daily.  Dosage reduction not needed in renal function impairment

  • Child:             Loading dose PO <1 year 0.045 mg/kg, 1-2 years 0.04 mg/kg, >2 years 0.03 mg/kg divided into 3, 4, or more portions with >6 hours between doses; maintenance dose PO 1/10 loading dose

Drug interactions:

  • Alprazolam, amiodarone, diltiazem, verapamil, bepridil, nitrendipine, quinidine, carvedilol, cyclosporine, erythromycin and tetracycline (change in bacterial flora causing effect may persist for months), hydroxychloroquine, NSAIDS, azole antifungals, omeprazole, lansoprazole, propafenone, quinine, spironolactone, tacrolimus:  May cause increased digoxin levels

  • Charcoal: reduced digitalis levels

  • Beta-Blockers: Potentiation of bradycardia

  • Succinylcholine: increased arrhythmias

 

Special considerations:

  • Listed adverse effects are mostly signs of toxicity

  • When digitalis indicated digoxin is 1st line drug because of shorter -life and faster clearance in the event toxicity develops.

  • Rule out digitalis toxicity if nausea, vomiting, or arrhythmias develop

  • Therapeutic range: 9-25 ng/ml

    

 
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