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Last Updated: July 19, 2019

Phenytoin is an anti-seizure medication. It is used to prevent partial seizures, tonic-clonic seizures, but not absence seizures. It may also be used to treat certain heart arrhythmias or neuropathic pain. It can be taken intravenously or by mouth.

Common side effects include nausea, increased hair growth, stomach pain, poor coordination, loss of appetite, and enlargement of the gums. Potentially serious side effects include self harm, sleepiness, liver problems, low blood pressure, bone marrow suppression and toxic epidermal necrolysis.

Phenytoin should be used with caution in patients having low blood pressure, heart failure, liver disease, suicidal tendencies, kidney disorders, vitamin D deficiency, diabetes and porphyria. It should not be used in people having allergy towards Phenytoin or other ingredients in the medicine or people suffering from certain heart conditions. There is evidence that use during pregnancy results in abnormalities in the baby. It appears to be safe to use during breastfeeding.

Take this medication orally as per your doctor’s prescription, with plenty of water. Avoid consumption of alcohol during the treatment. If for some reason you cannot take the medicine orally, it may be administered by a healthcare professional as an injection into a muscle or a vein, or by diluting it and giving it as a drip into a vein. The intravenous form generally begins working within 30 minutes and is effective for 24 hours. Blood levels of the patient can be measured to determine the suitable dose of the medicine.

Information given here is based on the salt content of the medicine. Uses and effects of the medicine may vary from person to person. It is advisable to consult a Neurologist before using this medicine.
  • Trigeminal Neuralgia

  • Allergy

    Not recommended in the patients with known allergy to Phenytoin.
  • Is It safe with alcohol?

    Phenytoin may cause excessive drowsiness and calmness with alcohol.
  • Are there any pregnancy warnings?

    Phenytoin is unsafe to use during pregnancy.
    There is positive evidence of human fetal risk, but the benefits from use in pregnant women may be acceptable despite the risk, for example in life-threatening situations. Please consult your doctor.
  • Are there any breast-feeding warnings?

    Phenytoin is safe to use during lactation. \nHuman studies have shown that either the drug does not pass into the breastmilk in significant amount or is not expected to cause toxicity to the baby.
  • Is it safe to drive while on this medicine?

    Phenytoin may make you feel dizzy, sleepy, tired, or decrease alertness. If this happens, do not drive.
  • Does this affect kidney function?

    Phenytoin is probably safe to use in patients with kidney disease. Limited data available suggests that dose adjustment of Phenytoin may not be needed in these patients. Please consult your doctor.
  • Does this affect liver function?

    Phenytoin should be used with caution in patients with liver disease. Dose adjustment of Phenytoin may be needed. Please consult your doctor.
  • Missed Dose instructions

    Take the missed dose as soon as you remember. If it’s almost time for your next dose, skip the missed dose. Do not double your dose to make up for the missed dose.
  • Overdose instructions

    Seek emergency medical treatment or contact the doctor if any symptoms of the overdose like uncontrolled body movements, slurred speech appear.
  • India

  • United States

  • Japan

Below is the list of medicines, which contains Phenytoin as ingredient

Phenytoin is an anticonvulsant which is known to prevent seizures by causing a voltage-dependent block of voltage gated sodium channels. It acts by increasing sodium efflux from the neurons of the motor cortex which reduces the post-tetanic potentiation at synapses. This inhibits the cortical seizure foci from spreading to adjacent areas, thus stabilizing the threshold against hyperexcitability.

Whenever you take more than one medicine, or mix it with certain foods or beverages, you"re at risk of a drug interaction.

  • Interaction with Medicine

    Serenace 5Mg Injection 1Ml

    Paliris 3Mg Tablet

    Barbinol 20mg/5ml Syrup

Ques: What is Phenytoin?

Ans: Phenytoin is a salt which performs its action by reducing the abnormal and excessive activity of the nerve cells in the brain. Phenytoin is used to treat conditions such as Seizures and Status Epilepticus.

Ques: What are the uses of Phenytoin?

Ans: Phenytoin is a medication, which is used for the treatment and prevention from conditions such as a Migraine and Cardiac Arrhythmias. Apart from these, it can also be used to treat conditions like Seizures and Status Epilepticus. The patient should inform the doctor about any ongoing medications and treatment before using Phenytoin to avoid undesirable effects.

Ques: What are the Side Effects of Phenytoin?

Ans: Phenytoin is a salt which has some commonly reported side effects. These side effects may or may not occur always and some of them are rare but severe. This is not a complete list and if you experience any of the below-mentioned side effects, contact your doctor immediately. Here are some side effects of Phenytoin which are as follows: Decreased coordination, Nervousness, Unsteadiness, Shaking of hands or feet, Unusual facial expressions, Trouble sleeping, Uncontrolled eye movements, Yellow colored eyes or skin, Skin rash, and Headache. It is a list of possible side-effects which may occur due to the constituting ingredients of Phenytoin.

Ques: What are the instructions for storage and disposal Phenytoin?

Ans: Phenytoin should be kept in a cool dry place and in its original pack. Make sure this medication remains unreachable to children and pets. The patient should consult a doctor for its further uses and side effects and should inform the doctor about any ongoing medications and treatment before using to avoid undesirable effects. It is a prescribed medication.

Ques: Should I use Phenytoin empty stomach, before food or after food?

Ans: This medication is to be consumed orally. The salts involved in this medication react properly if it is taken with the food. If you take it on an empty stomach, it might upset your stomach. Please consult the doctor before using Phenytoin.

Ques: How long do I need to use Phenytoin before I see improvement of my conditions?

Ans: The time taken by this medication to improve your health is unknown. Thus it is advised to use this medication for the time period it is prescribed by your doctor. Using this medication longer then its prescribed time may cause some side effects to the patient. Please consult your doctor before using Phenytoin.

Ques: Is there any food or drink I need to avoid?

Ans: You can follow your normal diet under the usage of this medication. Avoidance of any specific food product is not required. Though staying away from practices like drinking and smoking can improve your health.

Ques: Will Phenytoin be more effective if taken in more than the recommended dose?

Ans: Excess of usage of this medication can trigger side effects. The salts involved may cause inadequate effects to your health and can damage your liver if Phenytoin is taken more than its prescribed dosage or taken more times then its prescribed frequency.
Disclaimer: The information produced here is best of our knowledge and experience and we have tried our best to make it as accurate and up-to-date as possible, but we would like to request that it should not be treated as a substitute for professional advice, diagnosis or treatment.

Lybrate is a medium to provide our audience with the common information on medicines and does not guarantee its accuracy or exhaustiveness. Even if there is no mention of a warning for any drug or combination, it never means that we are claiming that the drug or combination is safe for consumption without any proper consultation with an expert.

Lybrate does not take responsibility for any aspect of medicines or treatments. If you have any doubts about your medication, we strongly recommend you to see a doctor immediately.

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Table of Content
About Phenytoin
What are the uses of Phenytoin
What are the contraindications of Phenytoin ?
What are the side effects of Phenytoin ?
Key highlights of Phenytoin
What are the dosage instructions?
Where is the Phenytoin approved?
Medicines containing Phenytoin
How does this medication work?
What are the interactions of Phenytoin ?
FAQs about Phenytoin