Three Part Question
In [patients with digoxin induced life-threatening ventricular dysrhythmias] is [magnesium or lidocaine or phenytoin] superior in [suppressing dysrhythmias or inproving mortality]
A 65 y.o. presents tachycardic, hypotensive and decreased LOC. ECG reveals ventricular tachycardia. As your staff places the pads for cardioeversion you discover he has been on digoxin for the past three years. You remember Digoxin Fab fragment, not cardioversion, is the treatment for digoxin induced ventricular dysrhythmias; however, you wonder if there are other therapies that maybe beneficial to your patient.
medline using OVID interface
(digoxin and toxicity and (dysrhythmia or arrhythmia or ventricular) and (magnesium or lidocaine or phenytoin or amiodarone)).mp.
matched 35 papers, of which 3 were relevent
|Author, date and country
||Study type (level of evidence)
|Kinlay S, Buckley NA|
|A patient with digoxin toxicity, ventricular tachycardia and slightly elevated serum magnesium||Case report||conversion to a stable junctional rhythem with magnesium infusion||case report|
|R Maheswaran, M G Bramble, and C A Hardisty|
1983 August 6
|A patient in ventricular fibrillation following a large digoxin ingestion.||Case Report||failed to convert with electrical cardioversion||case control. Large acute ingestion|
|failed to convert with sodium bicarbonate|
|failed to convert with lidocaine|
|Successfully converted to a stable rhythem with amiodarone|
|A patient with large acute digoxin ingestion in ventricular fibrillation||case control||failed to convert with lidocaine||case control|
|failed to convert with phenytoin|
|Converted to stable rhythem following magnesium|
|Singh RB, Dube KP, Srivastav PK.|
|19 children with heart failure on digoxin therapy. 3 of whom developed dysrhythmia||observational||magnesium successfully treated all dysrhythmias||observational. Children|
Digoxin toxicity can result in any dysrhythmia as a result of its suppressant and excitatory effects. Most concerning are ventricular dysrhythmias. Digoxin Fab antibody fragments are the treatment of choice for life-threatening dysrhythmias; however, when Digoxin Fab fragments are not immediately available temporizing therapies maybe necessary. Phenytoin and Lidocaine are thought to depress ventricular automaticity. Magnesium is thought to decrease ventricular irritability by competing with digoxin at the Na+K+ATPase.
Clinical Bottom Line
Magnesium, phenytoin, and lidocaine are acceptable temporizing therapies in life-threatening, digoxin induced ventricular dysrhythmias. There is insufficient evidence to promote one therapy over another. Amiodarone maybe considered in dysrhythmias refractory to the above therapies.
- Kinlay S, Buckley NA Magnesium sulfate in the treatment of ventricular arrhythmias due to digoxin toxicity. Journal of Toxicology - Clinical Toxicology. 33(1):55-9, 1995.
- R Maheswaran, M G Bramble, and C A Hardisty Massive digoxin overdose: successful treatment with intravenous amiodarone. British Medical Journal 1983 August 6; 287(6389): 392–393.
- French JH Magnesium therapy in massive digoxin intoxication Annals of Emergency Medicine Volume 13, Issue 7, Pages 562-566 (July 1984)
- Singh RB, Dube KP, Srivastav PK. Hypomagnesemia in relation to digoxin intoxication in children. American Heart Journal 1976 Aug;92(2):144-7.