Dilantin (phenytoin) is an anti-epileptic drug, also called an anticonvulsant. It works by slowing down impulses in the brain that cause seizures.

Dilantin is used to control seizures. Phenytoin does not treat all types of seizures, and your doctor will determine if it is the right medicine for you.

Take Dilantin exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Swallow an extended-release capsule whole and do not crush, chew, break, or open it.

Dilantin Infatabs chewable tablets are not for once-per-day dosing. You must take them 2 or 3 times per day. Follow your doctor's dosing instructions very carefully.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

You may need frequent blood tests. You may also need a blood test when switching from one form of phenytoin to another. Visit your doctor regularly.

Tell your doctor if Dilantin does not seem to work as well in controlling your seizures. Do not stop using Dilantin suddenly, even if you feel fine. Stopping suddenly may cause increased seizures. Follow your doctor's instructions about tapering your dose.

In case of emergency, wear or carry medical identification to let others know you have seizures.

Phenytoin can cause swelling in your gums. Brush and floss your teeth and visit your dentist regularly to help prevent this problem.

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

You should not use Dilantin 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 this medicine 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 Dilantin, 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.

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.

Headache, nausea, vomiting, constipation, dizziness, feeling of spinning, drowsiness, trouble sleeping, or nervousness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Phenytoin may cause swelling and bleeding of the gums. Massage your gums and brush and floss your teeth regularly to minimize this problem. See your dentist regularly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: slow heartbeat, unusual eye movements, loss of coordination, slurred speech, confusion, muscle twitching, double or blurred vision, tingling of the hands/feet, facial changes (e.g., swollen lips, butterfly-shaped rash around the nose/cheeks), excessive hair growth, increased thirst or urination, unusual tiredness, bone or joint pain, easily broken bones.

A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor right away if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior including signs of depression, suicidal thoughts/attempts, thoughts about harming yourself.

For males, in the very unlikely event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and seek immediate medical attention, or permanent problems could occur.

Get medical help right away if any of these rare but very serious side effects occur: uncontrolled muscle movements, signs of liver problems (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine), easy bruising/bleeding.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

How should I use this medicine?

Take this medicine by mouth with a glass of water. Chew it or swallow whole. Follow the directions on the prescription label. Take this medicine with food if it upsets your stomach. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking this medicine suddenly. This increases the risk of seizures. Your doctor will tell you how much medicine to take. If your doctor wants you to stop the medicine, the dose will be slowly lowered over time to avoid any side effects.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for selected conditions, precautions do apply.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular checks on your progress. This medicine needs careful monitoring. Your doctor or health care professional may schedule regular blood tests.

Wear a medical ID bracelet or chain, and carry a card that describes your disease and details of your medicine and dosage times.

Do not change brands or dosage forms of this medicine without discussing the change with your doctor or health care professional.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Birth control pills may not work properly while you are taking this medicine. Talk to your doctor about using an extra method of birth control.

This medicine can cause unusual growth of gum tissues. Visit your dentist regularly. Problems can arise if you need dental work, and in the day to day care of your teeth. Try to avoid damage to your teeth and gums when you brush or floss your teeth.

Do not take antacids at the same time as this medicine. If you get an upset stomach and want to take an antacid or medicine for diarrhea, make sure there is an interval of 2 to 3 hours before or after you took your phenytoin.

The use of this medicine may increase the chance of suicidal thoughts or actions. Pay special attention to how you are responding while on this medicine. Any worsening of mood, or thoughts of suicide or dying should be reported to your health care professional right away.

Women who become pregnant while using this medicine may enroll in the North American Antiepileptic Drug Pregnancy Registry by calling 1-888-233-2334. This registry collects information about the safety of antiepileptic drug use during pregnancy.

This medicine may cause a decrease in vitamin D and folic acid. You should make sure that you get enough vitamins while you are taking this medicine. Discuss the foods you eat and the vitamins you take with your health care professional.