Home Cerebyx - Fosphenytoin (Injection Route)

Cerebyx – Fosphenytoin (Injection Route)


Description and Brand Names of Cerebyx – Fosphenytoin (Injection Route)

US Brand Name

  1. Cerebyx


Fosphenytoin injection is used to control certain types of seizures (convulsions) in the treatment of epilepsy. It is also used to prevent and treat seizures that occur during brain surgery. This medicine is an anticonvulsant that works in the brain tissue to stop seizures.

This medicine is to be given only by or under the direct supervision of a doctor.

This product is available in the following dosage forms:

  • Solution

Before Using Cerebyx – Fosphenytoin (Injection Route)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of fosphenytoin injection in the pediatric population. Safety and efficacy have not been established.


Appropriate studies on the relationship of age to the effects of fosphenytoin injection have not been performed in the geriatric population. However, elderly patients are more likely to have age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving fosphenytoin injection.



There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Amifampridine
  • Artemether
  • Boceprevir
  • Delavirdine
  • Lumefantrine
  • Lurasidone
  • Maraviroc
  • Piperaquine
  • Praziquantel
  • Ranolazine
  • Rilpivirine
  • Telaprevir

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Abiraterone Acetate
  • Afatinib
  • Apazone
  • Apixaban
  • Atazanavir Sulfate
  • Axitinib
  • Beclamide
  • Bedaquiline
  • Bortezomib
  • Bosutinib
  • Cabazitaxel
  • Cabozantinib
  • Canagliflozin
  • Clozapine
  • Cobicistat
  • Crizotinib
  • Cyclophosphamide
  • Dabrafenib
  • Dasatinib
  • Dolutegravir
  • Dopamine
  • Dronedarone
  • Elvitegravir
  • Enzalutamide
  • Erlotinib
  • Eslicarbazepine Acetate
  • Ethosuximide
  • Etravirine
  • Everolimus
  • Ezogabine
  • Fentanyl
  • Fluoxetine
  • Fluvastatin
  • Halothane
  • Hydrocodone
  • Ibrutinib
  • Ifosfamide
  • Imatinib
  • Infliximab
  • Irinotecan
  • Ivabradine
  • Ivacaftor
  • Ixabepilone
  • Ketoconazole
  • Ketorolac
  • Lapatinib
  • Lidocaine
  • Linagliptin
  • Lopinavir
  • Macitentan
  • Methotrexate
  • Mifepristone
  • Nifedipine
  • Nilotinib
  • Nimodipine
  • Ondansetron
  • Orlistat
  • Pazopanib
  • Perampanel
  • Pixantrone
  • Pomalidomide
  • Ponatinib
  • Posaconazole
  • Regorafenib
  • Reserpine
  • Rifampin
  • Rivaroxaban
  • Rocuronium
  • Roflumilast
  • Romidepsin
  • Sertraline
  • Simeprevir
  • Sofosbuvir
  • St John’s Wort
  • Sunitinib
  • Tacrolimus
  • Temsirolimus
  • Thiotepa
  • Ticagrelor
  • Tolvaptan
  • Trabectedin
  • Vandetanib
  • Vemurafenib
  • Vincristine Sulfate
  • Vincristine Sulfate Liposome
  • Vinflunine
  • Voriconazole
  • Vortioxetine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acetaminophen
  • Acetazolamide
  • Acyclovir
  • Amiodarone
  • Amitriptyline
  • Amprenavir
  • Aprepitant
  • Atorvastatin
  • Betamethasone
  • Bexarotene
  • Bleomycin
  • Busulfan
  • Capecitabine
  • Carbamazepine
  • Carboplatin
  • Caspofungin
  • Chloramphenicol
  • Cimetidine
  • Ciprofloxacin
  • Cisplatin
  • Clarithromycin
  • Clobazam
  • Clofazimine
  • Clopidogrel
  • Cortisone
  • Cyclosporine
  • Desogestrel
  • Dexamethasone
  • Diazepam
  • Dicumarol
  • Dienogest
  • Digitoxin
  • Diltiazem
  • Disopyramide
  • Disulfiram
  • Doxepin
  • Doxorubicin
  • Doxorubicin Hydrochloride Liposome
  • Drospirenone
  • Estradiol Cypionate
  • Estradiol Valerate
  • Ethinyl Estradiol
  • Ethynodiol Diacetate
  • Etonogestrel
  • Felbamate
  • Fluconazole
  • Fludrocortisone
  • Fluorouracil
  • Fluvoxamine
  • Folic Acid
  • Fosamprenavir
  • Gefitinib
  • Ginkgo
  • Ibuprofen
  • Imipramine
  • Isoniazid
  • Itraconazole
  • Levodopa
  • Levomethadyl
  • Levonorgestrel
  • Levothyroxine
  • Medroxyprogesterone Acetate
  • Meperidine
  • Mestranol
  • Methoxsalen
  • Methsuximide
  • Miconazole
  • Midazolam
  • Nafimidone
  • Nelfinavir
  • Nilutamide
  • Nisoldipine
  • Norelgestromin
  • Norethindrone
  • Norgestimate
  • Norgestrel
  • Ospemifene
  • Oxcarbazepine
  • Paclitaxel
  • Pancuronium
  • Paroxetine
  • Phenprocoumon
  • Piperine
  • Prednisolone
  • Prednisone
  • Progabide
  • Quetiapine
  • Quinidine
  • Quinine
  • Remacemide
  • Rifapentine
  • Risperidone
  • Rufinamide
  • Sabeluzole
  • Shankhapulshpi
  • Simvastatin
  • Sirolimus
  • Sulfamethizole
  • Sulfamethoxazole
  • Sulfaphenazole
  • Sulthiame
  • Telithromycin
  • Tenidap
  • Theophylline
  • Tiagabine
  • Ticlopidine
  • Ticrynafen
  • Tirilazad
  • Tizanidine
  • Tolbutamide
  • Topiramate
  • Trazodone
  • Triamcinolone
  • Trimethoprim
  • Tubocurarine
  • Valproic Acid
  • Vecuronium
  • Verapamil
  • Vigabatrin
  • Viloxazine

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Ethanol

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Blood or bone marrow problems (e.g., agranulocytosis, leukopenia, or thrombocytopenia) or
  • Diabetes or
  • Heart failure or
  • Hypotension (low blood pressure) or
  • Lymphadenopathy (lymph node problems) or
  • Porphyria (an enzyme problem) – Use with caution. May make these conditions worse.
  • Heart block (e.g., Adams-Stokes syndrome, AV block, or sinoatrial block) or
  • Sinus bradycardia (slow heartbeat) – Should not be used in patients with these conditions.
  • Hypoalbuminemia (low albumin in the blood) or
  • Kidney disease or
  • Liver disease – Use with caution. The effects may be increased because of slower removal from the body.

Proper Use of Cerebyx – Fosphenytoin (Injection Route)

A nurse or other trained health professional will give you this medicine in a hospital. This medicine is given as a shot into one of your muscles or through a needle placed in one of your veins.

Your doctor will only give you a few doses of this medicine until your condition improves. You will be switched to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.


It is very important that your doctor check your progress closely while you are receiving this medicine. This is to see if the medicine is working properly and to allow for a change in the dose. Blood tests may be needed to check for any unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away. Your doctor may want you to join a pregnancy registry for patients taking a seizure medicine.

Do not receive this medicine while you are also taking delavirdine (Rescriptor®). Using these medicines together may cause delavirdine to not work as well for you.

This medicine may cause some people to become dizzy, lightheaded, faint, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert and able to see well.

Do not stop using this medicine without first checking with your doctor. Stopping the medicine suddenly may cause your seizures to return or to occur more often.

Stop using this medicine and tell your doctor right away if you develop a fever; rash; swollen, painful, or tender lymph glands in the neck, armpit, or groin; unusual bleeding or bruising; or yellow eyes or skin. These may be symptoms of a serious and life-threatening condition called Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).

If you develop a skin rash, hives, or any allergic reaction to this medicine, stop using the medicine and check with your doctor as soon as possible.

Tell your doctor right away if your skin feels like it is burning, crawling, or itching, or if you have numbness, prickling, “pins and needles”, or tingling feelings after receiving fosphenytoin injection.

This medicine may cause purple glove syndrome. Tell your doctor right away if you have skin discoloration, pain, or swelling at the injection site after receiving this medicine.

This medicine may affect blood sugar levels. If you notice a change in the results of your blood or urine sugar tests or if you have any questions, check with your doctor.

Birth control pills may not work while you are using this medicine. To keep from getting pregnant, use another form of birth control along with your birth control pills. Other forms include a condom, a diaphragm, or a contraceptive foam or jelly.

Avoid drinking alcohol while you are receiving this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of Cerebyx – Fosphenytoin (Injection Route)

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

  1. Blurred vision
  2. confusion
  3. dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  4. feeling of warmth or heat
  5. flushing or redness of the skin, especially on the face and neck
  6. headache
  7. sweating
  8. unusual tiredness or weakness

Less common

  1. Anxiety
  2. bruising
  3. burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
  4. changes in patterns and rhythms of speech
  5. convulsions
  6. difficulty with speaking
  7. drooling
  8. dry mouth
  9. fast, pounding, or irregular heartbeat or pulse
  10. hyperventilation
  11. irritability
  12. itching skin
  13. lack of coordination
  14. large, flat, blue, or purplish patches in the skin
  15. loss of balance control
  16. muscle trembling, jerking, or stiffness
  17. nervousness
  18. problems with movement, walking, or speech
  19. restlessness
  20. shakiness in the legs, arms, hands, or feet
  21. shortness of breath
  22. shuffling walk
  23. slurred speech
  24. stiffness of the limbs
  25. trouble with sleeping
  26. twisting movements of the body
  27. uncontrolled movements, especially of the face, neck, and back
  28. unsteadiness, trembling, or other problems with muscle control or coordination
  29. vomiting


  1. Abdominal or stomach pain
  2. absence of or decrease in body movement
  3. aggressive or angry
  4. agitation
  5. black, tarry stools
  6. bleeding gums
  7. bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  8. blistering, burning, crusting, dryness, or flaking of the skin
  9. blood in the urine or stools
  10. bloody nose
  11. bluish color of the fingernails, lips, skin, palms, or nail beds
  12. body aches or pain
  13. bone pain
  14. burning while urinating
  15. change in consciousness
  16. change in personality
  17. change in the ability to see colors, especially blue or yellow
  18. change in the color of the treated skin
  19. chest pain or discomfort
  20. cloudy urine
  21. cold, clammy skin
  22. congestion
  23. cough or hoarseness
  24. cough producing mucus
  25. coughing or spitting up blood
  26. crying
  27. decrease in frequency of urination
  28. decrease in the amount of urine
  29. deep or fast breathing with dizziness
  30. delusions
  31. dementia
  32. depression
  33. diarrhea
  34. difficulty in passing urine (dribbling)
  35. difficulty with breathing
  36. difficulty with moving
  37. difficulty with swallowing
  38. dilated neck veins
  39. dizziness, fainting, or lightheadedness
  40. drowsiness
  41. dryness or soreness of the throat
  42. dysphoria
  43. euphoria
  44. eye pain
  45. feeling of unreality
  46. feeling that others are watching you or controlling your behavior
  47. feeling that others can hear your thoughts
  48. feeling, seeing, or hearing things that are not there
  49. fever or chills
  50. flushed, dry skin
  51. frequent urination
  52. fruit-like breath odor
  53. general feeling of discomfort or illness
  54. general physical wasting or malnutrition associated with severe illness
  55. greatly increased frequency of urination or amount of urine
  56. headache, severe and throbbing
  57. hives or welts
  58. inability to move the legs or arms
  59. inability to sit still
  60. increase in body movements
  61. increase in heart rate
  62. increased hunger
  63. increased sensitivity of the skin to sunlight
  64. increased thirst
  65. increased urination
  66. increased volume of pale, dilute urine
  67. increased watering of the mouth
  68. irregular breathing
  69. itching, scaling, severe redness, soreness, or swelling of the skin
  70. joint pain
  71. leg cramps
  72. loss of appetite
  73. loss of bladder control
  74. loss of consciousness
  75. loss of memory
  76. loss of strength or energy
  77. lower back or side pain
  78. muscle aches, pains, or stiffness
  79. muscle twitching or jerking
  80. muscular tenderness, wasting, or weakness
  81. nausea or vomiting
  82. need to keep moving
  83. no blood pressure or pulse
  84. not breathing
  85. numbness of the feet, hands, and around the mouth
  86. numbness or tingling in the face, arms, hands, feet, or lips
  87. pain or tenderness around the eyes and cheekbones
  88. pale skin
  89. paralysis of one side of the body
  90. paranoia
  91. pinpoint red spots on the skin
  92. pounding in the ears
  93. problems with memory
  94. quick to react or overreact emotionally
  95. rapid breathing
  96. rapid heartbeat
  97. rapid weight gain
  98. rapidly changing moods
  99. rash with flat lesions or small raised lesions on the skin
  100. redness of the skin
  101. redness or other discoloration of the skin
  102. rhythmic movement of the muscles
  103. seizures
  104. sense of detachment from self or body
  105. severe constipation
  106. severe headache
  107. severe mood or mental changes
  108. severe pain in the chest
  109. severe sunburn
  110. severe vomiting
  111. shivering
  112. sleeplessness
  113. small lumps under the skin
  114. small red or purple spots on the skin
  115. sneezing
  116. sores, ulcers, or white spots on the lips or in the mouth
  117. spots on your skin resembling a blister or pimple
  118. stiff neck
  119. stopping of heart
  120. stuffy or runny nose
  121. sudden onset of severe breathing difficulty
  122. sudden shortness of breath or troubled breathing
  123. sunken eyes
  124. swelling of the face, fingers, feet, ankles, or lower legs
  125. swelling of the tongue
  126. swollen joints
  127. swollen, painful, or tender lymph glands in the neck, armpit, or groin
  128. tightness of the chest or wheezing
  129. troubled breathing with exertion
  130. twisting movements of body
  131. unable to sleep
  132. unconsciousness
  133. uncontrolled movements, especially of the face, neck, and back
  134. unexplained weight loss
  135. unusual behavior
  136. unusual bleeding or bruising
  137. unusual weak feeling
  138. voice changes
  139. vomiting of blood or material that looks like coffee grounds
  140. weakness or heaviness of the legs
  141. weight gain
  142. wrinkled skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Continuing ringing or buzzing or other unexplained noise in the ears
  2. decreased awareness or responsiveness
  3. hearing loss
  4. severe sleepiness
  5. sleepiness or unusual drowsiness
  6. uncontrolled eye movements

Less common

  1. Back pain
  2. change in taste or bad, unusual, or unpleasant (after) taste
  3. change in vision
  4. double vision
  5. feeling of constant movement of self or surroundings
  6. impaired vision
  7. lack or loss of strength
  8. pelvic pain
  9. seeing double
  10. sensation of spinning


  1. Acid or sour stomach
  2. belching
  3. bigger, dilated, or enlarged pupils (black part of eye)
  4. bloated
  5. burning feeling in the chest or stomach
  6. burning, dry, or itching eyes
  7. change in color vision
  8. difficulty having a bowel movement (stool)
  9. difficulty seeing at night
  10. discharge, excessive tearing
  11. ear pain
  12. excess air or gas in the stomach or intestines
  13. frequent urge to defecate
  14. full feeling
  15. heartburn
  16. increased sense of hearing
  17. increased sensitivity of the eyes to light
  18. indigestion
  19. itching of the vagina or genital area
  20. loss of taste
  21. pain during sexual intercourse
  22. passing gas
  23. redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid
  24. stomach discomfort, upset, or pain
  25. straining while passing stool
  26. tenderness in the stomach area
  27. thick, white vaginal discharge with no odor or with a mild odor
  28. transient, mild, or pleasant aromatic odor
  29. vaginal yeast infection
  30. weight loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.