Phenytoin



Phenytoin is a potent medication to treat central nervous system seizures, but its antiarrhythmic actions are limited. It effectively abolishes ab­normal automaticity caused by digitalis toxicity. Sinus nodal automaticity and AV conduction are only minimallly affected by phenytoin. Pheny-toin’s electrophysiological effects in vitro appear similar to those of lidocaine. It exerts minimal he­modynamic effects. Phenytoin may be successful in treating atrial and ventricular arrhythmias due to digitalis toxicity but is much less effective in treating arrhythmias of other etiologies.