macrobid and Cerebyx Interactions

Interactions between macrobid(nitrofurantoin) and Cerebyx (fosphenytoin)

nitrofurantoin and fosphenytoin (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.