From the Guidelines
Phenytoin is a recommended treatment for ventricular dysrhythmias caused by digitoxin overdose, and it should be administered until digoxin-specific antibody fragments (digoxin-Fab) can be given. According to the 2023 American Heart Association guidelines 1, phenytoin, along with lidocaine or bretylium, may be reasonable to administer for treating ventricular dysrhythmias caused by digitalis and other cardiac glycoside poisoning. The guidelines suggest that these medications can be used until digoxin-Fab can be administered, which is the first-line treatment for digoxin or digitoxin poisoning 1.
Key points to consider when using phenytoin for digitoxin overdose include:
- Phenytoin can help reduce life-threatening arrhythmias caused by digitoxin toxicity
- It should be administered intravenously, with careful monitoring of cardiac function and blood pressure
- The dose and administration rate should be adjusted according to the patient's response and the severity of the overdose
- Phenytoin is not a substitute for digoxin-Fab, which is the preferred treatment for digitoxin overdose 1
It is essential to note that the primary treatment for digitoxin overdose is the administration of digoxin-specific antibody fragments (digoxin-Fab) 1. Phenytoin and other medications should only be used as adjunctive therapy until digoxin-Fab can be given. The use of phenytoin in this context is based on the recommendation that it may be reasonable to administer for treating ventricular dysrhythmias caused by digitalis and other cardiac glycoside poisoning 1.
From the Research
Treatment of Digitoxin Overdose
- Phenytoin is used in the treatment of digitoxin overdose due to its ability to improve AV-conduction and accelerate the metabolism of digitoxin 2
- The use of phenytoin is preferred over other antiarrhythmic drugs as it has less effect on AV-conduction 2
- Treatment of digitoxin overdose also involves gastric aspiration and lavage, followed by instillation of activated charcoal to interrupt the enterohepatic circulation of digitoxin 2
- Repeated doses of charcoal should be given to ensure effective treatment 2
Alternative Treatment Options
- Digoxin-specific antibody fragments (digoxin-Fab) are also used in the treatment of digoxin toxicity, which can be effective in severe cases 3, 4, 5
- CytoSorb hemoadsorption is another treatment option that has shown promise in the treatment of severe digitoxin intoxication 6
- The choice of treatment depends on the severity of the overdose, the patient's condition, and the availability of treatment options 3, 4, 6, 5
Important Considerations
- Monitoring of the patient's condition is crucial after treatment, as there is a risk of rebound toxicity 4
- The dose of digoxin-Fab required for treatment depends on the amount ingested and the serum digoxin concentration, but is not essential for determining the dose 3, 4
- Phenytoin and other treatment options should be used under medical supervision, as they can have adverse effects and interact with other medications 2, 3, 4, 6, 5