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Fosphenytoin (FOS fen i toyn)

Brand Names: U.S.

Cerebyx

Brand Names: Canada

Cerebyx®

Warning

  • This drug may cause risky heartbeats or low blood pressure if given too fast. Your doctor will watch your heart closely when you get this drug.

What is this drug used for?

  • It is used to help control certain kinds of seizures.

What do I need to tell my doctor BEFORE I take this drug?

  • If you have an allergy to fosphenytoin, phenytoin, or any other part of this drug.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you have heart problems.
  • If you are taking delavirdine.
This is not a list of all drugs or health problems that interact with this drug.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

  • Tell dentists, surgeons, and other doctors that you use this drug.
  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this drug affects you.
  • Do not stop taking this drug all of a sudden without calling your doctor. You may have a greater risk of side effects. If you need to stop this drug, you will want to slowly stop it as ordered by your doctor.
  • Have your blood work checked often. Talk with your doctor.
  • If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
  • Talk with your doctor before you drink wine, beer, or mixed drinks.
  • Take good care of your teeth. See a dentist often.
  • Very bad and sometimes deadly skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis) have happened with this drug. People of Asian descent are most likely to get these. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
  • This drug may affect certain lab tests. Be sure your doctor and lab workers know you take this drug.
  • If you are 65 or older, use this drug with care. You could have more side effects.
  • Birth control pills and other hormone-based birth control may not work as well to prevent pregnancy. Use some other kind of birth control also like a condom when taking this drug.
  • This drug may cause harm to the unborn baby if you take it while you are pregnant.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this drug while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of high blood sugar like confusion, feeling sleepy, more thirst, more hungry, passing urine more often, flushing, fast breathing, or breath that smells like fruit.
  • Signs of low mood (depression), thoughts of killing yourself, nervousness, emotional ups and downs, thinking that is not normal, anxiety, or lack of interest in life.
  • Signs of low potassium levels like muscle pain or weakness, muscle cramps, or a heartbeat that does not feel normal.
  • Signs of infection. These include a fever of 100.5°F (38°C) or higher, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, wound that will not heal, or anal itching or pain.
  • Very bad dizziness or passing out.
  • Fast or slow heartbeat.
  • A heartbeat that does not feel normal.
  • Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
  • Change in thinking clearly and with logic.
  • Ringing in ears.
  • Hearing loss.
  • Swollen or sore gums.
  • Shakiness.
  • Any bruising or bleeding.
  • Not able to control eye movements.
  • Feeling very tired or weak.
  • If seizures are worse or not the same after starting this drug.
  • Irritation or swelling where the shot was given.
  • Change in color of skin where drug is used.
  • A burning, numbness, or tingling feeling that is not normal.
  • A very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause very bad health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
  • A very bad and sometimes deadly effect has happened in people taking drugs for seizures like this drug. Call your doctor right away if you have swollen glands; fever; rash; chest pain; unable to pass urine or change in the amount of urine passed; or signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
  • Lymph node problems like cancer have happened in people taking this drug. It is not known if this drug may be the cause. Talk with your doctor if you have swollen glands.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
  • Dizziness.
  • Feeling sleepy.
  • Dry mouth.
  • Headache.
  • Upset stomach or throwing up.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to your national health agency.

How is this drug best taken?

Use this drug as ordered by your doctor. Read and follow the dosing on the label closely.
  • It is given as a shot into a muscle or vein.
  • Do not change the dose or stop this drug. This could cause seizures. Talk with your doctor.

What do I do if I miss a dose?

  • Call your doctor to find out what to do.

How do I store and/or throw out this drug?

  • This drug will be given to you in a hospital or doctor’s office. You will not store it at home.
  • Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.

General drug facts

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else’s drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, pharmacist, or other health care provider.

Consumer Information Use and Disclaimer

This information should not be used to decide whether or not to take this medicine or any other medicine. Only your healthcare provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your healthcare provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

Copyright

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