Acute digoxin Overdose Indications:
- Cardiac arrest
- life threatening cardia dysrhythmia
- ingested dose >10mg (adult) or >4mg (child)
- serum digoxin level >15 mol/L (12 ng/ml)
- serum potassium >5 mol/L
Chronic digoxin Overdose Indications:
- Cardiac arrest
- Life threatening cardiac dysrhythmia
- Cardiac dysrhythmia or increased automaticity not likely to be tolerated for a prolonged period
- Moderate-to-severe GI symptoms
- Any symptoms in the presence of impaired renal function
Place the patient in an area capable of resuscitation and on cardiac monitoring.
Calculate the dose required and dilute in 100ml of 0.9% saline and administer over 30 mins (this may change once a new study is released called DORA – watch this space)
The dose calculated presumes that one ampule will bind 0.5mg of digoxin
- Give high dose digoxin immune Fab (20 ampules if available) by rapid IV injection.
Acute digoxin Overdose:
- Known digoxin dose: Number of ampoules = ingested dose (mg) x 0.8 (bioavailability) x 2
- Unknown dose: 5 ampoules if the patient is haemodynamically stable / 10 ampoules if unstable. Repeat 5 ampoules every 30 minutes until reversal of digoxin is achieved.
Chronic digoxin poisoning:
- Number of ampoules = [serum digoxin (ng/ml) x body weight (kg)] / 100
- An alternative method is to give 2 ampoules and observe for a clinical response. If no improvement after 30 minutes then give a further 2 ampoules. However, it can take up to 4 hours for the fun clinical effects to be observed.
- Digoxin toxicity may recur beyond 24 hours and necessitate further administration of digoxin immune Fab. Therefore keep your patient monitored and do not discharge within 24 hours.
Other cardiac glycoside poisoning:
- If the patient is stable then give 5 ampoules every 30 minutes until toxicity is reversed.
- Up to 30 ampoules have been used to reverse oleander poisoning
- Exacerbation of atrial fibrillation or cardiac failure
- Digoxin levels will rise post administration of the immune Fab as the assays will measure both free and Fab-bound digoxin, Ask for the “free level” for more accurate serum monitoring.
- Antman EM, Wenger TL, Butler VP et al. Treatment of 150 cases of life-threatening digitalis intoxication with digoxin-specific Fab antibody fragments: final report of a multicenter study. Circulation 1990; 81(6):1744-1752.
- Bateman DN. Digoxin-specific antibody fragments: how much and when? Toxicological Reviews 2004; 23(3):135-143.
- Di Domenico R, Walton S, Sanoski CA et al. Analysis of the use of digoxin Fab for the treatment of non life threatening digoxin toxicity. Journal of Cardiovascular Pharmacology and Therapeutics 2000; 5(2):77-85.
- Eddleston M, Rajapakse S, Rajakanthan et al. Anti-digoxin Fab fragments in cardiotoxicity induced by ingestion of yellow oleander: a randomised controlled trial. Lancet 2000; 355(9208):967-972.
- Lapostelle F, Borron SW, Verdier C et al. Digoxin-specifc Fab fragments in single first-line therapy in digitalis poisoning. Critical Care Medicine 2008; 36:3014-3018.
- Woolf AD, Wenger T, Smith TW et al. The use of digoxin-specific Fab fragments for severe digitalis intoxication in children. New England Journal of Medicine 1992; 326:1739-1744.