<p>Causes enhanced toxicity with allopurinol, cisplatin. Ifosfamide enhances the anticoagulant effect of warfarin. CYP2A6 inducers (e.g. amobarbital, pentobarbital, phenobarbital, rifampin and secobarbital) may reduce serum levels of ifosfamide while the inhibitors (e.g. isoniazid, methoxsalen and miconazole) may increase its serum levels. CYP3A4 inducers (e.g. aminoglutethimide, carbamazepine, nafcillin, nevirapine, phenobarbital, phenytoin, and rifamycins) may reduce serum levels of ifosfamide while the inhibitors (e.g. azole antifungals, clarithromycin, diclofenac, doxycycline, erythromycin, imatinib, isoniazid) may increase its serum levels.</p>