Dilantin

Potentiated by acute alcohol ingestion, amiodarone, antiepileptic agents (eg, ethosuximide, felbamate, oxcarbazepine, methsuximide, topiramate), azoles (eg, fluconazole, ketoconazole, itraconazole, miconazole, voriconazole), benzodiazepines (eg, chlordiazepoxide, diazepam), capecitabine, chloramphenicol, disulfiram, estrogens, fluorouracil, fluoxetine, fluvastatin, fluvoxamine, halothane, H₂-blockers (eg, cimetidine), isoniazid, methylphenidate, omeprazole, phenothiazines, salicylates, sertraline, succinamides (eg, ethosuximide), sulfonamides, ticlopidine, tolbutamide, trazodone, warfarin. Antagonized by anticancer drugs (eg, bleomycin, carboplatin, cisplatin, doxorubicin, methotrexate), chronic alcohol ingestion, carbamazepine, diazepam, folic acid, fosamprenavir, nelfinavir, reserpine, rifampin, ritonavir, St. John’s wort, sucralfate, theophylline, vigabatrin. Antagonizes anticoagulants (eg, apixaban, dabigatran, edoxaban, rivaroxaban), antiepileptic agents (eg, carbamazepine, felbamate, lacosamide, lamotrigine, topiramate, oxcarbazepine), atorvastatin, fluvastatin, simvastatin, ticagrelor, antivirals (eg, efavirenz, lopinavir/ritonavir, indinavir, nelfinavir, ritonavir, saquinavir), albendazole, chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, nifedipine, nimodipine, nisoldipine, praziquantel, quetiapine, verapamil. Reduces efficacy of concomitant azoles, corticosteroids, doxycycline, estrogens, furosemide, irinotecan, oral contraceptives, paclitaxel, paroxetine, quinidine, rifampin, sertraline, teniposide, theophylline, vitamin D, warfarin. Concomitant fosamprenavir/ritonavir may potentiate amprenavir. Concomitant neuromuscular blockers (eg, pancuronium, vecuronium, rocuronium, cisatracurium); may need higher infusion rate. Variable effects with phenobarbital, valproic acid, sodium valproate. Absorption decreased by calcium, antacids. Increased risk of hyperammonemia with concomitant valproate; monitor.