Antidote and definitive therapy
›Digoxin specific immune Fab
›Indications
›Ventricular tachycardia or ventricular fibrillation
›Class I
›Symptomatic bradycardia with high grade AV block
›Class I
›Cardiac arrest attributed to cardiac glycoside poisoning
›Class I
›Hyperkalemia with suspected acute cardiac glycoside poisoning
›Class I
›Dosing by known ingestion
›Vials equals digoxin dose ingested in mg times 0.8
›Tablet bioavailability assumption 0.8
›Full neutralization option vials equals total body load mg divided by 0.5
›Each vial binds 0.5 mg digoxin equivalent
›Dosing by serum level and weight
›Formula option A US package insert
›Vials equals serum digoxin ng/mL times weight kg divided by 100
›Formula option B EU SmPC
›Vials equals serum digoxin ng/mL times weight kg divided by 200
›Conversion support
›Digoxin nmol/L times 0.781 equals digoxin ng/mL
›Administration
›Initiate infusion over at least 30 minutes if stable
›Slower rate if infusion reaction
›If cardiac arrest then bolus dosing strategy per local protocol
›Repeat dose after 15 to 30 minutes if inadequate response
›Adverse effects and monitoring
›Anaphylaxis and infusion reaction readiness
›Epinephrine and airway equipment available
›Worsening heart failure due to loss of inotropy
›Diuresis and oxygen support as needed
›Hypokalemia after reversal
›Frequent potassium monitoring
Supportive care and decontamination
›Decontamination for acute ingestion
›Activated charcoal single dose
›1 g/kg PO or NG
›Typical adult dose 50 g
›Airway protection prerequisite
›Activated charcoal multiple dose
›Consider for massive ingestion or prolonged absorption
›0.5 g/kg every 4 hours
›Ileus and aspiration risk monitoring
›Fluids
›Isotonic crystalloid for dehydration
›Cautious in heart failure
›Electrolyte correction
›Potassium repletion in hypokalemia
›Slow IV replacement with telemetry
›Avoid overcorrection in chronic toxicity
›Magnesium sulfate for hypomagnesemia
›2 g IV over 10 to 20 minutes
›Repeat dosing to upper normal range
Bradyarrhythmia management while awaiting Fab
›Atropine
›Initiate 1 mg IV
›Repeat every 3 to 5 minutes
›Maximum 3 mg
›Limited efficacy in infranodal block
›Early pacing planning
›Transcutaneous pacing
›If unstable bradycardia refractory to atropine
›Analgesia and sedation if time allows
›Transvenous pacing
›If persistent high grade AV block with instability
›Cardiology support
Ventricular dysrhythmia management while awaiting Fab
›Lidocaine
›Initiate 1 to 1.5 mg/kg IV bolus
›Repeat 0.5 to 0.75 mg/kg every 5 to 10 minutes
›Maximum 3 mg/kg
›Infusion
›Initiate 1 to 4 mg per minute
›Phenytoin
›Initiate 15 mg/kg IV
›Maximum infusion rate 50 mg per minute
›Hypotension monitoring
›Electrical therapy caveats
›Synchronized cardioversion for unstable VT
›Use lowest effective energy
›Fab prioritized when available
›Defibrillation for VF or pulseless VT
›Standard ACLS energy
›Avoided or caution agents
›Amiodarone
›Can increase digoxin levels and worsen toxicity
›Procainamide
›Hypotension and conduction worsening concern
›Quinidine
›Potent digoxin level increase
Hyperkalemia in suspected cardiac glycoside poisoning
›Antidote first strategy
›Digoxin specific Fab as definitive therapy
›Potassium reduction expected after reversal
›Temporizing measures
›Insulin regular 10 units IV
›Dextrose 25 g IV if glucose less than 11 mmol/L
›Glucose monitoring every 30 to 60 minutes
›Nebulized albuterol 10 to 20 mg
›Tachycardia monitoring
›Sodium bicarbonate 50 mmol IV
›Consider if metabolic acidosis
›Calcium salts
›Controversial historical avoidance
›If immediately life threatening ECG instability and Fab not immediately available then consider calcium with toxicology guidance
›Potassium removal
›Loop diuretic if adequate renal function
›Volume status monitoring
›Potassium binders
›Delayed onset
›Dialysis
›For refractory hyperkalemia due to renal failure
›Digoxin removal limited