Phenytoin is an anticonvulsant drug used in the prophylaxis and control of various types of seizures. Phenytoin is an anti-epileptic drug that slows down impulses in the brain that cause seizures. It is used to control seizures, but it may cause harm to an unborn baby, and it can interact with many other medicines. Phenytoin sodium, an antiepileptic drug, has been a cornerstone in the treatment of epilepsy for decades. This medication is widely used to manage various types of seizures, but its applications extend beyond just seizure control. Dilantin (phenytoin) is used to treat epilepsy. Learn side effects, dosage, drug interactions, warnings, patient labeling, reviews, and more.