DISOPYRAMIDE AND PHENYTOIN
Serum disopyramide levels are reduced by phenytoin and may fall below therapeutic levels. Loss of arrhythmic control may occur. Fosphenytoin, a prodrug of phenytoin, may interact similarly.
Antiarrhythmic response and serum disopyramide levels (where possible) should be well monitored. Adjust the disopyramide dose as necessary. Serum disopyra- mide levels appear to return to normal within 2 weeks of withdrawing the phenytoin.
Antiarrhythmic response and serum disopyramide levels (where possible) should be well monitored. Adjust the disopyramide dose as necessary. Serum disopyra- mide levels appear to return to normal within 2 weeks of withdrawing the phenytoin.