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In this Article

• What is phenytoin (Dilantin Infatabs)?
• What are the possible side effects of phenytoin?
• What is the most important information I should know about phenytoin?
• What should I discuss with my healthcare provider before taking phenytoin?
• How should I take phenytoin?
• What happens if I miss a dose?
• What happens if I overdose?
• What should I avoid while taking phenytoin?
• What other drugs will affect phenytoin?
• Where can I get more information?

What should I discuss with my healthcare provider before taking phenytoin?

You should not use this medication if you are allergic to phenytoin.

If you have any of these other conditions, you may need a dose adjustment or special tests to safely use this medication:

• liver disease;
• porphyria;
• diabetes; or
• a vitamin D deficiency or any other condition that causes thinning of the bones.

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.

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.

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.

Phenytoin can affect your blood sugar. If you are a diabetic, check your blood sugar regularly while you are taking this medication.

FDA pregnancy category D. This medication can cause harm to an unborn baby. Phenytoin may also not be as effective in reducing seizures if taken during pregnancy. Do not use phenytoin without your doctor's consent if you are pregnant. Tell your doctor if you become pregnant during treatment. Use an effective form of birth control while you are using this medication.

Phenytoin can make birth control pills less effective. Use a non-hormonal form of birth control (such as a condom or diaphragm with spermicide) to prevent an unintended pregnancy.

Phenytoin can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take phenytoin?

Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

Do not crush, chew, break, or open an extended-release capsule. Swallow the pill whole. It is specially made to release medicine slowly in the body. Breaking or opening the pill would cause too much of the drug to be released at one time.

Do not use any phenytoin capsule or tablet that has changed colors. Call your doctor for a new prescription.

The chewable tablet may be chewed, broken, or crushed before swallowing, or it may be swallowed whole.

Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

To be sure this medication is helping your condition, your blood may need to be tested on a regular basis. You may also need a blood test when switching from one form of phenytoin to another. Do not miss any scheduled appointments.

If you are taking phenytoin to treat seizures, keep taking the medication even if you feel fine. You may have an increase in seizures if you stop taking phenytoin. Follow your doctor's instructions.

Do not change your dose of phenytoin without your doctor's advice. Tell your doctor if the medication does not seem to work as well in treating your condition.

Carry an ID card or wear a medical alert bracelet stating that you are taking phenytoin, in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you should know that you are taking a seizure medication.

Store phenytoin at room temperature away from moisture, light, and heat.