LEFLUNOMIDE AND PHENYTOIN
In vitro studies have found that the active metabolite of leflunomide (A771726) is an inhibitor of CYP2C9, the isoenzyme concerned with the metabolism of phenytoin and fosphenytoin.
Although no cases of phenytoin toxicity appear to have been reported as a result of this interaction, caution would be advisable on concurrent use, especially as leflunomide has, in practice, been seen to inhibit the metabolism of other CYP2C9 substrates.
Although no cases of phenytoin toxicity appear to have been reported as a result of this interaction, caution would be advisable on concurrent use, especially as leflunomide has, in practice, been seen to inhibit the metabolism of other CYP2C9 substrates.