Toxicology

Cardiac effects associated with digoxin toxicity include second- and third-degree heart block,

tachyarrhythmias, and bradyarrhythmias. More specific examples include fascicular tachycardia,

confusion, and visual disturbances.

Consider decontamination strategies if patients present within 2 hours of overdose.

Multidose activated charcoal is beneficial because of the enterohepatic recirculation of digoxin. Load

50–100 g; then 10 g/hour, 10–20 g every 2 hours, or 40 g every 4 hours (Postgrad Med 1993;69:337-

9).

Colestipol or cholestyramine is an effective drug-binding alternative to charcoal, but it may not be

Hemodialysis is not considered effective.

Correct serum potassium concentration to a goal of 3.5–4 mEq/L.

Correct serum magnesium concentration to a goal of 1.5–2.2 mg/dL.

Correct serum calcium concentration to a goal of 8.5–10.5 mg/dL.

Treat symptomatic bradyarrhythmias with atropine 0.5 mg intravenously.

Digoxin immune antigen-binding fragments (Fab)

Antibodies that bind to digoxin molecules that are then renally excreted

84):

Life-threatening arrhythmias: asystole, ventricular fibrillation or tachycardia, complete heart

block, symptomatic bradycardia

ii.

Evidence of end-organ damage (e.g., renal failure, altered mental status)

iii.

Hyperkalemia (greater than 5–5.5 mEq/L)

Products:

Digibind (Digoxin Immune Fab): 38 mg per vial

ii.

DigiFab (Digoxin Immune Fab): 40 mg per vial

If amount of digoxin ingested is unknown: 10–20 vials for acute toxicity or 6 vials for chronic

toxicity

ii.

If the amount of digoxin ingested is known:

Dose (vials) = total body load (0.8 × mg of digoxin ingested)/0.5

iii.

If digoxin concentration is known:

Dose (vials) = [serum digoxin concentration (ng/mL) × weight (kg)]/100

iv.

May consider lower doses of 1 or 2 vials (40–80 mg) for acute ingestions with repeat doses if

necessary

Adverse effects include heart failure exacerbation, atrial fibrillation, orthostatic hypotension,

hypokalemia, and phlebitis.

Monitor vital signs every 30–60 minutes initially. Goal HR of greater than 60 beats/minute and

asymptomatic