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Phenytoin (injection)

Generical name: Phenytoin (injection) FEN-i-toyn
Names of brands: Dilantin, Phenytoin, Sodium Prompt
Dosage form: injectable solution (50 mg/mL)
Classifications of drugs: Group I antiarrhythmics, hydantoin anticonvulsants

What is Phenytoin?

Phenytoin injections are an anticonvulsant medicine that is prescribed to manage prolonged seizures (status epilepticus). Phenytoin injections can also be used to avoid seizures during surgical procedures. Phenytoin injections can also be used to treat conditions that are not mentioned in this guide.

Side effects of Phenytoin

Contact emergency medical assistance. If you notice symptoms or warning signs of an allergic response (hives or breathing difficulties and swelling of your throat or face) or an extreme skin reaction (fever and sore throat, burning of your eyes, skin irritation, or red or purple itching that can cause peeling and blisters), Consult a doctor when you experience a severe reaction to a drug that affects the body in a variety of ways. Symptoms may include an itch on your skin and fever, swelling of the glands, muscle pains, abnormal bruising, severe weakness, or yellowing of the eye or skin. A phenytoin injection could cause serious heart issues. Tell your caregiver when you feel faint, lightheaded, or tired before or following an injection.

Phenytoin could cause serious adverse side effects. Consult your doctor immediately if you experience:

  • A feeling of lightheadedness, as if you're passing out;
  • The mind, or unusual thoughts or behaviors;
  • Fever, chills, sore throats, swelling glands;
  • Gums that are red or swollen mouth sores, red gums
  • Simple bleeding, unusual bruising;
  • Bleeding, swelling, pain, or any other irritations where the injection was administered
  • A purple-colored discoloration on your skin around the IV needle or dispersing away from the site in the area where the injection was made (may be seen for a few days following the injection);
  • Increased thirst, increased urination, or
  • Liver problems: loss of appetite, stomach pain, dark urine stool that is colored with clay, jaundice (yellowing of the eyes or skin).

Common adverse effects of phenytoin could include:

  • Drowsiness, confusion;
  • Speech slurred;
  • Unusual eye movements abnormal eye movement
  • Issues with balance or muscle movements.

This isn't a complete list of all the side effects. Other effects may also be present. Contact your doctor for advice regarding medical effects. You can report symptoms to the FDA at 1-800-FDA-1088.


A phenytoin injection may cause life-threatening heart problems. Phenytoin is typically administered by injection only when you are not able to take the medication by mouth.

If you can before receiving an injection of phenytoin, inform your doctor if you've experienced any serious heart issues or heartbeats that are slow which led to you fainting.

Your breathing rate, heart rate, blood pressure, heart rate, and other vital indicators will be closely monitored. Contact your physician when you feel faint, lightheaded, or breathless following an injection or during the course of it.

If it is possible, prior to receiving a phenytoin injection, inform your medical professionals if you've ever experienced:

  • A heart disease known asav block"; 2nd and 3rd degrees of "av block";
  • Low heartbeats have led the patient to fall unconscious.
  • Liver issues due to phenytoin
  • If you're currently taking lavirdine (rescriptor),

Speak to your doctor if you have ever suffered from:

  • Kidney or liver disease;
  • Diabetes;
  • Porphyria (a genetic disorder of enzymes that results in symptoms that affect the nervous system, skin, or nerves) or
  • If you're of asian descent, you might require a special blood test to assess your chance of developing an allergic reaction to phenytoin on your skin.

Inform your physician that you're pregnant. Phenytoin may cause harm to the unborn baby; however, having a seizure during pregnancy can harm both the pregnant mother and the baby. The benefits of preventing seizures could outweigh the risks for the infant. If you've received an injection of phenytoin during pregnancy, make sure you inform the doctor who delivers your baby about the use of phenytoin. Both you and your baby could require medication to stop bleeding during the delivery as well as shortly after the birth. If you're expecting, then your name might be added to an OB-GYN registry to monitor how phenytoin affects the baby.

Phenytoin may make the birth control pill less efficient. Talk to your doctor about non-hormonal birth control (condom diaphragm, diaphragm containing diaphragm, spermicide) to avoid pregnancy. It might not be safe to breastfeed while taking this medication. Consult your physician about any potential risks. In the event of an emergency situation, you might not be able to inform your caregivers that you are breastfeeding or pregnant. It is important that the doctor caring for the baby or your pregnancy is aware that you have received this medication.

How to take Phenytoin?

Phenytoin is injected in the muscle or as an injection into the vein. The healthcare professional will administer the injection if you're in a position to not take the medication via mouth. Your blood pressure, breathing levels, oxygen levels, and other vital indicators are closely monitored. Inform your doctor that you are experiencing any pain, burning, or swelling in the area of your IV needle when you inject phenytoin.

If you take phenytoin, then you may require a regular blood test. It is also possible to undergo a blood test when changing from injectable form to the oral version of the drug. It is not advisable to stop taking phenytoin abruptly, even if you feel well. A sudden stopcould trigger seizures. Follow the instructions of your physician when tapering your dose. Phenytoin may cause swelling in your gums. Take extra care of your teeth hygiene when you are receiving the phenytoin. Cleanse and floss your teeth on a regular basis.

What happens if I miss the dose?

Since you'll be receiving the injections of phenytoin in a medical setting, you're not likely to skip the dose.

What happens when I take too much?

Get medical attention immediately, or make a call for help at the Poison Help Line at 1-800-222-1222. A phenytoin overdose can cause death. Some signs of an overdose include twitching eyes and slurred speech. Other symptoms include shaking, loss of balance, muscle stiffness or vomiting, nausea, weakness, and fainting. You may also feel lightheaded, faint, and have slow or shallow breathing.

What should be avoided?

Avoid driving or engaging in hazardous activities until you are aware of the effects of phenytoin on your body. The way you react could be impaired.

Beware of drinking alcohol while you take phenytoin. Alcohol consumption can increase levels of phenytoin in your blood and cause more adverse effects. Drinking alcohol regularly can reduce the level of phenytoin in your blood, which may increase the risk of having seizures.

Talk to a pharmacist or doctor prior to taking over-the-counter medicines like omeprazole, cimetidine, St. John's wort, minerals, and vitamins that contain folic acids.

Interaction with other drugs

There are times when it's not recommended to take certain medications in combination. Certain drugs may affect the blood levels of other medications that you take, which can cause more side effects or make the drugs less effective.

Numerous drugs interact with phenytoin. The interactions may not be included in this article. Inform your doctor about all other medicines you are taking as well as any medications you begin or stop using while you are on phenytoin. This includes over-the-counter and prescription medications, vitamins, and herbal supplements.




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