Phenytoin serum levels are markedly and rapidly increased by the concurrent use of
disulfiram.
Phenytoin toxicity has been seen in 2 patients.
This interaction seems to occur in most patients and develops rapidly. Recovery may take 2 to 3 weeks after the
disulfiram is withdrawn. Monitor
phenytoin levels carefully during concurrent use.
Phenytoin dosage reductions may be needed, but it may be difficult to maintain the balance required.