Dilantin Infatabs

  • Seizure disorders

Dilantin Infatabs Generic Name & Formulations

General Description

Phenytoin 50mg; chewable tabs.

Pharmacological Class


How Supplied

Caps 30mg—100; 100mg—100, 1000; Tabs—100; Susp—8oz


Generic Availability


Dilantin Infatabs Indications


Tonic-clonic, psychomotor and neurosurgically induced seizures.

Dilantin Infatabs Dosage and Administration


May be chewed or swallowed whole. Initially 2 tabs 3 times daily. Maintenance dose: 6–8 tabs daily in divided doses; may increase to 12 tabs daily if necessary.


Initially 5mg/kg per day in 2–3 equally divided doses. Increase weekly if needed. Usual maintenance: 4–8mg/kg per day; max 300mg daily.

Dilantin Infatabs Contraindications


History of prior acute hepatotoxicity due to phenytoin. Concomitant delavirdine.

Dilantin Infatabs Boxed Warnings

Not Applicable

Dilantin Infatabs Warnings/Precautions


Suicidal tendencies (monitor). Diabetes. Discontinue if acute hepatotoxicity occurs; do not restart. Monitor serum levels when switching between sodium salt of phenytoin (caps) and free acid form (suspension, Infatabs). Discontinue and evaluate at the 1st sign of a rash. Increased risk of SJS/TEN if positive for HLA-B*1502 or in CYP2C9*3 carriers (esp. Asian ancestry); consider avoiding as an alternative for carbamazepine. Adjust dose gradually. Angioedema. Underlying cardiac disease. Use proper dental hygiene. Hormonal contraception. Monitor bone mineral density with chronic use. Porphyria. Intermediate or poor CYP2C9 metabolizers. Renal and/or hepatic impairment. Hypoalbuminemia. Elderly. Debilitated. Pregnancy: avoid. Nursing mothers: not recommended.

Dilantin Infatabs Pharmacokinetics

See Literature

Dilantin Infatabs Interactions


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.

Dilantin Infatabs Adverse Reactions

Adverse Reactions

Nystagmus, ataxia, slurred speech, decreased coordination, somnolence, mental confusion, headaches, dizziness, cerebellar atrophy, nausea, vomiting, constipation, gingival hyperplasia, osteomalacia, blood dyscrasias, lymphadenopathy, cardiac effects, hepatic disease, hyperglycemia, SLE, hypertrichosis, lab test abnormality; rare: serious dermatologic reactions (eg, SJS, TEN, AGEP, DRESS), multiorgan hypersensitivity (may be fatal).

Dilantin Infatabs Clinical Trials

See Literature

Dilantin Infatabs Note


To enroll in the North American Antiepileptic Drug Pregnancy Registry call (888) 233-2334.

Dilantin Infatabs Patient Counseling

See Literature