In this session, we will be discussing the consumer medication information for phenytoin, trade name DilantinTM.

What it’s for & How to take

Phenytoin is an anti-seizure medication. This medication helps restore chemical balance to the brain. This medication is used to prevent and control various types of seizures.

This medication is sometimes used to treat other conditions. Talk with your doctor or pharmacist if you are prescribed this medication to treat something that is not listed here.

Phenytoin is taken either once daily or divided throughout the day as directed by your doctor. Phenytoin should be taken with a full glass of water and may be taken with or without food. Phenytoin comes in a capsule, liquid, and a chewable tablet. If you are taking the capsule, swallow it whole. Do not open or crush the capsule.

Take phenytoin at least 2 hours before or 6 hours after vitamins or antacids such as TumsTM or MylantaTM. Some foods high in calcium such as yogurt or milk may also block this medication from working. Ask your pharmacist what you can and can’t have with this medication

Take your dose at evenly spaced intervals to maintain a constant level of medication in your body. Your doctor may gradually increase your dose over a few weeks to a couple of months.

Your dose is based on your condition, and response to treatment. Do not stop taking this medication without talking to your doctor first. Some conditions may worsen if this medication is stopped quickly.

If you forget to take a dose, take it as soon as you remember. If it is near the time of your next dose, skip it and continue with your normal dose time. Do not take a double dose to make up the missed dose.

Warnings & Cautions

  • While taking phenytoin, a small number of people may experience depression or suicidal thoughts. Let your doctor know if you or your family notice any unusual changes in your mood.
  • Infants born to mothers who are taking phenytoin are at risk. This medication should only be used during pregnancy when the benefit to the mother is greater than the risk to the unborn baby. This medication passes into breast milk. Talk with your doctor before breastfeeding while taking phenytoin.
  • This medication may make you dizzy, drowsy, or blur your vision. Do not drive or do any activity that requires focus and attention until you are sure you can do them safely. Avoid alcoholic beverages while taking phenytoin.

Interactions & Side Effects

  • Tell your pharmacist or doctor all your medication allergies so they may determine if phenytoin is safe for you to take.
  • Avoid dangerous drug interactions. Tell your pharmacist or doctor all the other medication you are taking, including over the counter supplements, even if you don’t take them very often. If you currently take any hormonal birth control medication, both the phenytoin and birth control effectiveness may be decreased. Talk with your doctor about this.
  • Ask your doctor if this medication is safe to take with your current health conditions. Tell your doctor if you have any history of liver or kidney disease, any blood disorder, diabetes, or a history of depression or alcohol abuse.
  • While taking phenytoin, you may feel a decrease in balance, dizzy, blurred vision, tremor, confusion, or a headache. If these or any other unwanted side effects persist, contact your doctor or pharmacist to talk about it with them.
  • Call your doctor right away if you have any slurred speech, tingling in the hands or feet, swollen face, or unusual eye movements. Also, call your doctor right away if you have any seizures, flu symptoms such as fever or swollen glands, chest pain or abnormal heartbeat, trouble breathing, abdominal pain, yellowing of your eyes or any other significant side effects.
  • Seek immediate medical attention if you have a significant worsening of your mood or experience any suicidal thoughts.
  • Call emergency 911 if you have any symptoms of a heart attack such as chest and left arm pain, shortness of breath and sweating or if you have symptoms of a stroke such as weakness on one side of your body, slurred speech, sudden vision changes, and confusion.

If you have any questions about what you have heard, contact your pharmacist or doctor. This session does not include all the potential interactions or side effects that this medication may cause. Ask your pharmacist how your medication should be stored and how you should dispose of it when you are done taking it. Do not share your medication with anyone, ever. Remember, this is not meant to replace your counseling session with your pharmacist. In case of overdose, call your local poison control center at 1-800-222-1222.

Updated 7/20