Monday May 25, 2009
A note on Phenytoin use in Digitalis Toxicity

Ventricular tachycardia (V.Tach.) is common in Digitalis toxicity and may respond well to Phenytoin (Dilantin). Lidocaine is another useful choice but phenytoin depress the enhanced ventricular automaticity without significantly slowing AV conduction. Phenytoin may reverse digitalis-induced prolongation of AV nodal conduction. Phenytoin has been shown to dissociate the inotropic and dysrhythmic action of digitalis, thus suppressing digitalis-induced tachydysrhythmias without diminishing the contractile effects. In addition, phenytoin can terminate supraventricular dysrhythmias induced by digitalis, whereas lidocaine may not been as effective.

Phenytoin has been administered in boluses of 100 mg every 5-10 minutes up to a loading dose of 15 mg/kg.