nitrofurantoin-monohydrate-macrocrystals and Dilantin 125 Interactions

Interactions between nitrofurantoin-monohydrate-macrocrystals(nitrofurantoin) and Dilantin 125 (phenytoin)

nitrofurantoin and phenytoin (Moderate Drug-Drug)

MONITOR: One patient experienced seizures and a drop in phenytoin levels while taking concurrent nitrofurantoin. Phenytoin levels rose when nitrofurantoin was discontinued. The mechanism is unknown but may be related to induction of hepatic metabolism by nitrofurantoin. A similar reaction may occur with other hydantoins.

MANAGEMENT: Phenytoin serum concentrations should be monitored during coadministration of these agents. Patients should be advised to promptly report loss of seizure control to their caregiver.