Some very limited evidence suggests that imipramine can raise
serum phenytoin levels.
Phenytoin possibly reduces
serum desipramine levels. Fosphenytoin, a prodrug of
phenytoin, may interact similarly.
Care should be taken if deciding to use this combination in epileptic patients. If concurrent use is undertaken the effects should be very well monitored. Note that the
tricyclics lower the convulsive threshold.