anti-seizure drug in Torsade de pointes

Q: Which anti-seizure drug can be used to treat Torsade de pointes if conventional therapy fails?

Answer: Phenytoin 

First described in 1969, phenytoin can be utilized when nothing is left to overcome TdeP! It is said to be effective, particularly in arrhythmia, due to digoxin overdose. 

The proposed mechanism is that phenytoin reduces the activity of cardiac ryanodine Receptor 2, which is known for its cardioprotective action.

#cardiology

#pharmacology

References:

1. Yager N, Wang K, Keshwani N, Torosoff M. Phenytoin as an effective treatment for polymorphic ventricular tachycardia due to QT prolongation in a patient with multiple drug intolerances. BMJ Case Rep. 2015 Jun 12;2015:bcr2015209521. doi: 10.1136/bcr-2015-209521. PMID: 26071440; PMCID: PMC4480099.

2. Bhansali S, Tan RBM, Spilios M, Cecchin F. Use of supra-therapeutic phenytoin for management of ventricular arrhythmias in children: Case series and literature review. Pacing Clin Electrophysiol. 2022 Dec;45(12):1385-1389. doi: 10.1111/pace.14565. Epub 2022 Aug 15. PMID: 35903996.

3. Vukmir RB, Stein KL. Torsades de pointes therapy with phenytoin. Ann Emerg Med. 1991 Feb;20(2):198-200. doi: 10.1016/s0196-0644(05)81223-5. PMID: 1996806.