What is phenytoin?
Phenytoin is an anti-epileptic drug, also called an anticonvulsant. It works by slowing down impulses in the brain that cause seizures.
Phenytoin is used to control seizures. Phenytoin does not treat all types of seizures, and your doctor will determine if it is the right medication for you.
Phenytoin may also be used for purposes not listed in this medication guide.
What is the most important information I should know about phenytoin?
You should not use phenytoin if you also take delavirdine (Rescriptor), or if you are allergic to phenytoin, ethotoin (Peganone), fosphenytoin (Cerebyx), or mephenytoin (Mesantoin).
If you are pregnant, DO NOT START TAKING phenytoin unless your doctor tells you to. Phenytoin may cause harm to an unborn baby, but having a seizure during pregnancy could harm both the mother and the baby. If you become pregnant while taking phenytoin, DO NOT STOP TAKING the medicine without your doctor's advice. Seizure control is very important during pregnancy and the benefits of preventing seizures may outweigh any risks posed by using phenytoin.
You may have thoughts about suicide while taking this medication. Your doctor will need to check you at regular visits. Do not miss any scheduled appointments.
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, depression, anxiety, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
What should I discuss with my healthcare provider before taking phenytoin?
You should not use phenytoin if you also take delavirdine (Rescriptor), or if you are allergic to phenytoin, ethotoin (Peganone), fosphenytoin (Cerebyx), or mephenytoin (Mesantoin).
To make sure you can safely take phenytoin, tell your doctor if you have any of these other conditions:
liver disease;
lupus;
diabetes;
a vitamin D deficiency or any other condition that causes thinning of the bones;
porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system); or
if you drink large amounts of alcohol.
Your family or other caregivers should also be alert to changes in your mood or symptoms. Your doctor will need to check you at regular visits. Do not miss any scheduled appointments.
You may have thoughts about suicide while taking this medication. Tell your doctor if you have new or worsening depression or suicidal thoughts during the first several months of treatment, or whenever your dose is changed.
Patients of Asian ancestry may have a higher risk of developing a rare but serious skin reaction to phenytoin. Your doctor may recommend a blood test before you start the medication to determine your risk of this skin reaction.
FDA pregnancy category D. Phenytoin may cause harm to an unborn baby, but having a seizure during pregnancy could harm both the mother and the baby.
If you are pregnant, DO NOT START TAKING phenytoin unless your doctor tells you to. If you become pregnant while taking phenytoin, DO NOT STOP TAKING the medicine without your doctor's advice.
Seizure control is very important during pregnancy. The benefit of preventing seizures may outweigh any risks posed by taking phenytoin. Follow your doctor's instructions about taking phenytoin while you are pregnant.
Phenytoin can make birth control pills less effective. To prevent pregnancy while you are taking phenytoin, use a non-hormonal form of birth control (such as a condom or diaphragm with spermicide).
Phenytoin can pass into breast milk and may harm a nursing baby. You should not breast-feed while you are using phenytoin.