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Phenytoin

Phenytoin 50MG

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What is Phenytoin?

Phenytoin is a prescription medication used to treat epilepsy. The average price of Phenytoin is around $21 for a supply of 30, 50 mg capsules. Use our Rx.com savings offer to get great discounts on Phenytoin at participating pharmacies near you.

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What is Phenytoin ?

Phenytoin is a prescription medication used to treat epilepsy. The average price of Phenytoin is around $21 for a supply of 30, 50 mg capsules. Use our Rx.com savings offer to get great discounts on Phenytoin at participating pharmacies near you.
  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Bone fractures, pain, tenderness, or aching, pain in the back, ribs, arms, or legs, decrease in height
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Severe confusion, problems with balance or walking, slurred speech, tremors
  • Unusual bleeding, bruising, or weakness
  • Feeling agitated, depressed, nervous, or irritable, thoughts of hurting yourself or others, unusual mood or behavior
  • Slow growth in children
  • Slow heartbeat, chest pain or discomfort, lightheadedness, dizziness or fainting
  • Fever, chills, cough, sore throat, body aches
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.
  • This medicine may make you bleed, bruise, or get infections more easily. Take precautions to prevent illness and injury. Wash your hands often.
  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant.
  • Tell your doctor if you are breastfeeding, or if you have kidney disease, liver disease, heart disease, diabetes, porphyria, or a history of depression or mental problems.
  • This medicine may cause the following problems:Changes in mood or behavior, including thoughts of suicideSerious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and acute generalized exanthematous pustulosis (AGEP)Drug reaction with eosinophilia and systemic symptoms (DRESS), which may damage organs, including the liver, kidney, or heartHeart problems (including slow heartbeat)Liver problemsDecreased bone densityHigh blood sugar levels
  • This medicine may make you drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
  • This medicine may damage your gums. Brush and floss your teeth regularly and visit your dentist to help prevent these problems.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
What is phenytoin (Dilantin) used for?
Phenytoin, sold under the brand name Dilantin, is an anti-seizure (antiepileptic) medicine. It is FDA-approved to control tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures, and to prevent and treat seizures that happen during or after brain surgery. Your prescriber decides whether it is right for your specific seizure type.
What are the most common side effects of phenytoin?
Common side effects can include involuntary eye movements (nystagmus), unsteady walking or coordination problems (ataxia), slurred speech, drowsiness, and confusion, which may signal that the blood level is too high. With long-term use, phenytoin can also cause overgrowth of the gums and increased hair growth. Report any rash, fever, or unusual symptoms to your provider promptly, since serious reactions are possible.
What is a normal therapeutic level of phenytoin?
The usual target range for total phenytoin in the blood is about 10 to 20 mcg/mL. Levels above this range raise the risk of toxicity, while lower levels may not control seizures well. Your prescriber uses blood tests to keep your level in the right range for you.
Why does phenytoin require regular blood tests?
Phenytoin has a narrow therapeutic index, meaning the safe and effective dose is close to the level that can cause toxicity. Small changes in dose, other medicines, or how your body processes the drug can shift your level significantly. Regular blood tests let your prescriber confirm the level is in the target range and watch for effects on the liver and blood cells.
Can you stop taking phenytoin suddenly?
No. You should not stop phenytoin abruptly, because doing so can trigger seizures, including prolonged or repeated seizures. If a change is needed, your prescriber will taper the dose gradually and may adjust or add another medicine. Always make changes under medical supervision.
How much does Phenytoin cost without insurance?
The price of Phenytoin without insurance varies by pharmacy, dosage, and quantity. Rx.com compares cash prices at more than 60,000 US pharmacies so you can find the lowest price near you.
What are the common side effects of Phenytoin?
Common side effects of Phenytoin may include: Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, Blistering, peeling, or red skin rash, Bone fractures, pain, tenderness, or aching, pain in the back, ribs, arms, or legs, decrease in height, Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes, Severe confusion, problems with balance or walking, slurred speech, tremors. This is not a complete list — consult your pharmacist or doctor for full side effect information.
Is there a generic version of Phenytoin?
Generic versions may be available for Phenytoin. Generics contain the same active ingredients as brand-name drugs and are typically 80–90% cheaper. Search Phenytoin on Rx.com to compare generic and brand prices at pharmacies near you.
What is the cheapest pharmacy for Phenytoin?
The cheapest pharmacy for Phenytoin depends on your location and dosage. Rx.com compares prices at CVS, Walgreens, Walmart, Kroger, Costco, and thousands of independent pharmacies. Enter your ZIP code on Rx.com to find the lowest price for Phenytoin near you.

Phenytoin Coupons & Prices

Phenytoin 50MG

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Looking for a phenytoin coupon? Phenytoin is the generic form of Dilantin, a long-established anti-seizure medicine, and because it is available as a low-cost generic, most people can fill it affordably with a free discount coupon instead of paying full retail. Cash prices still vary widely from one pharmacy to the next, so comparing before you fill matters. Enter your ZIP above to see today's price at pharmacies near you, where Rx.com compares over 60,000 pharmacies to find the lowest phenytoin price with no insurance required.

What is phenytoin and how does it work?

Phenytoin is an anticonvulsant (antiepileptic) medicine in the hydantoin class. It works as a sodium channel blocker, calming the abnormal electrical activity in the brain that leads to seizures. It is the generic equivalent of the brand Dilantin, and is also sold under the brand names Phenytek and Dilantin Infatabs.

Phenytoin is FDA-approved to control tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures, and to prevent and treat seizures that occur during or after neurosurgery. It comes in several oral forms, including extended-release capsules, chewable tablets, and an oral suspension, as well as an injectable form used in hospital settings. Your prescriber will choose the form and dose that fit your condition.

Phenytoin cost and savings without insurance

Because phenytoin is available as an FDA-approved generic, it is one of the more affordable seizure medicines, and you do not need insurance to get a good price with a free Rx.com discount coupon. That said, the cash price can differ a lot between pharmacies in the same town, which is exactly why comparing pays off. Enter your ZIP above to see today's price near you and show the coupon at the pharmacy counter.

If you are prescribed brand-name Dilantin rather than the generic, the manufacturer (Pfizer) offers a savings program on the official Dilantin website; eligibility and terms vary and typically exclude government insurance, so check the details there. For most people, the generic plus an Rx.com coupon is the simplest way to keep costs down.

Phenytoin alternatives and related seizure medicines

Phenytoin is one of several antiepileptic drugs. If it is not the right fit for you, or you want to understand the options, your prescriber may discuss alternatives. Only a clinician can decide which is appropriate for your seizure type and health history.

You can compare the price of any of these on Rx.com. Never switch or stop a seizure medicine on your own — changes should always be made with your prescriber.

Safety and important warnings

Phenytoin has a narrow therapeutic index, meaning the difference between a helpful dose and a toxic one is small. Blood levels are usually kept in a target range of about 10 to 20 mcg/mL, and signs of toxicity can include involuntary eye movement (nystagmus), unsteady walking (ataxia), slurred speech, and confusion. Because of this, regular blood tests and dose adjustments are part of routine care. This is general information, not medical advice, so follow your provider's guidance.

The FDA label carries serious warnings. When given by rapid IV infusion, phenytoin can cause dangerous drops in blood pressure, slow heart rate, and cardiac arrest, so the infusion rate is strictly limited in hospital settings. Other important risks include serious skin reactions such as Stevens-Johnson syndrome and DRESS (the risk is higher in people of Asian ancestry who carry the HLA-B*1502 gene variant), liver injury, blood cell disorders, and, as with all antiepileptics, a small increased risk of suicidal thoughts or behavior. Phenytoin can harm a developing baby (fetal hydantoin syndrome), and long-term use may cause gum overgrowth and increased hair growth. It also interacts with many medicines because it is a strong liver-enzyme inducer. Do not stop phenytoin suddenly, as this can trigger seizures. Talk with your prescriber or pharmacist about your full medication list.

Sources & accuracy

This Phenytoin information was written and reviewed against authoritative U.S. medical sources — MedlinePlus (U.S. National Library of Medicine), DailyMed, and FDA prescribing information — and checked for accuracy. It is provided for education and is not a substitute for professional medical advice.

Verify the official label: Phenytoin on DailyMed (FDA)

Reviewed against FDA labeling · Last reviewed July 2026

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Medical disclaimer: This information is provided for general educational purposes only and is not medical advice. It is not a substitute for professional diagnosis or treatment. Always consult a licensed physician, pharmacist, or other qualified healthcare provider before starting, stopping, or changing any medication or treatment. Never disregard professional medical advice or delay seeking it because of something you read here. If you think you may have a medical emergency, call your doctor or 911 immediately.


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