Phenytoin Oral : Uses, Side Effects, Interactions

Phenytoin Suspension


GENERIC NAME(S): Phenytoin


Phenytoin is used to prevent and control seizures (also called an anticonvulsant or antiepileptic drug). It works by reducing the spread of seizure activity in the brain.

How To Use Phenytoin Suspension

Before starting to take Phenytoin, read the medication guide provided by your pharmacist and whenever you get refill. If you have any questions, ask your doctor or pharmacist.

Shake this medicine thoroughly before each dose. Take this medicine from mouth to 2 or 3 times a day, or direct your doctor. This product is not recommended for use once a day. If you get stomach, you can take it with meals.

Measure the dose carefully using special measurement equipment / spoon / syringe. Do not use domestic spoon because you can not get the right dose.

Use this drug regularly so that it can get the most benefit. It is important to take the time to absorb all the doses in order to maintain the quantity of medicines in your body at an ongoing level. Remember to use it at the same time each day. Dosage is based on your medical condition and medical reaction.

Antacid and nutritional tube-feeding (oral) products can reduce the absorption of Phenytoin. Do not take these products at the same time as you have a dietetic dose of phenytoin. Separate liquid nutrition products at least 1 hour before the phenytoin dose and according to your doctor’s guidance.

Do not stop taking this medicine without consultation with your doctor. When the medicine suddenly stops, the tour may get worse. Your dose may need to be gradually decreased.

Inform your doctor if your condition does not improve or gets worse.

Side Effects

Headache, nausea, vomiting, constipation, dizziness, feeling of spinning, drowsiness, trouble in sleep, or nervousness. If any of these effects persists or worsens, tell your doctor or pharmacist immediately.

Phenytoin can cause swelling and bleeding in the gums. Massage your gums and brush and flush your teeth regularly to reduce the problem. See your dentist regularly.

Remember that your doctor has prescribed this drug because he or she has decided that the benefit is higher than the risk of side effects. Many people using this drug do not have serious side effects.

Tell your doctor immediately if there are no potential but serious side effects: unusual movement of the eye, loss of coordination, slim speech, confusion, muscular dysfunction, double or blurred vision, hands / feet tingling, facial changes (Such as swelling) lips, nose / cheeks, butterfly size grains), hair growth, thirst or urination, abnormal fatigue, bone or joint pain, easy Broken bones.

In a small number of people who take anticonvulsants for any condition (such as visits, bipolar disorder, pain), can experience depression, thoughts / attempts of suicide, or other mental / mood problems. Tell your doctor immediately if you or your family / carer sees any unusual / sudden changes in your mood, thoughts, or behavior, including thoughts about depression, suicidal thoughts / attempts, self-harm.

For men, in the very unlikely event you have painful or prolonged pain for 4 or more hours, stop using this medicine and seek immediate medical attention, or may have permanent problems.

Get medical help immediately after any of these rare but very serious side effects: Stir in uncontrolled muscles, symptoms of liver problems (such as nausea / vomiting which does not stop, stomach / abdominal pain, eyes / skin Yellowing, black urination), easy injuries / hemorrhage.

A very serious allergic reaction to this drug is rare. However, if you see symptoms of a serious allergic reaction, get medical help, including: fever, swelling lymph nodes, rash, itching / swelling (especially the face / tongue / throat), severe dizziness, respiratory distress.

This is not a complete list of possible side effects. If you do not list other effects above, contact your doctor or pharmacist.

In America – Call your doctor for medical advice about side effects. You can notify the FDA of side effects on 1-800-FDA-1088 or

In Canada – Call your doctor for medical advice about side effects. You can report the health effects of Canada on 1-866-234-2345.


Before taking phenytoin, tell your doctor or pharmacist whether you are allergic to it; Or for other anti-seizure drugs (e.g., carbamazepine,  ethotoin,  phenobarbital,  ethosuximide,  trimethadione); Or if you have any other allergens. This product can have passive elements, which can cause allergic or other problems. Talk to your pharmacist for more details.

Before using this drug, tell your doctor or pharmacist your medical history, especially: the use of alcohol, certain blood conditions (porphyria), diabetes, liver disease (including liver disease due to the use of previous phenytoin) Lupus, folate or vitamin B-12 deficiency (megaloblastic anemia).

This drug may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or deaf. Unless you can safely do it, do not drive, use machinery, or do anything that requires caution. Limit alcoholic beverages. If you are using marijuana, talk to your doctor. Alcohol can also affect your blood level of this drug.

Tell your doctor that you are using phenytoin before surgery or any procedure that is unable to take you from the mouth.

If you have diabetes, then this medicine can increase your blood glucose level. Check your blood (or urine) glucose level, often guided by your doctor. Instantly report any unusual results according to the instructions. Your drug, exercise plan or diet may need to be adjusted.

Vitamin D supplements may be necessary to prevent osteoporosis (osteomalacia). Discuss this with your doctor.

During pregnancy, this drug should be used only when it is clearly necessary. It can harm an unborn child. However, since untreated seizures are a serious condition which can harm both pregnant women and their unborn children, do not stop taking this medicine unless directed by your doctor. If you are planning a pregnancy, become pregnant, or think that you may be pregnant, talk to your doctor immediately about the benefits and risks of using this drug during pregnancy. Since birth control pills, patches, implants and injections can not work if taken with this medicine (see also the drug interaction section), discuss the reliable forms of birth control with your doctor.

phenytoin passes in breast milk. Consult your doctor before breastfeeding.


See also the usage section.

Drug interactions can change how your medicines work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescriptions / non-prescription medicines and herbal products) and share it with your doctor and pharmacist. Do not start, stop or change any drug supplements without the approval of your doctor.

Some products that interact with this drug include: azapropazone,  darunavir,  delavirdine, dofetilide, etravirine, nisoldipine, rilpivirine, colesevelam, molindone, orlistat, pyridoxine(vitamin B6), sucralfate, telithromycin.

Other medicines can affect your body’s removal of phenytoin, which can affect how phenytoin works. Examples include amiodarone, azole antifungals (e.g  itraconazole), macrolide antibiotics (e.g erythromycin), estrogens, isoniazid, rifamycins (such as rifabutin), St. John’s wort, other anti-seizure medicines (such as valproic acid), among others.

phenytoin can accelerate the removal of other drugs from your body, which can affect how they work.  Examples of affected drugs include atazanavir, some drugs to treat cancer (such as imatinib, irinotecan), cobicistat, corticosteroids  (such as prednisone),  felodipine,  quetiapine,  quinidine,  suvorexant,  theophylline, vitamin D, among others.

This drug can reduce the effectiveness of hormonal birth control such as pills, patches, or rings. This can lead to pregnancy. Discuss with your doctor or pharmacist if you should use additional reliable birth control methods while using this medication. Tell your doctor also whether you have any new spots or breakthrough bleeding because these signs can be that your birth control is not working properly.

This product may affect the results of some lab tests. Ensure that the lab staff and your doctor know that you use this medicine.

Over Dose

If someone is treated and has serious symptoms like having trouble going out or breathing, call 911. Otherwise, call the Poison Control Center immediately. US residents can call their local venom control center at 1-800-222-1222. Canadians can call a provincial poison control center. Symptoms of overdose may include: severe mental / mood swings, severe drowsiness, loss of consciousness, slow breathing.


Do not share this medication with others.

Labs and / or medical tests (e.g, phenytoin blood levels, liver function tests) should be periodically monitoring your progress or checking side effects. Consult your doctor for more details.

Do not change this product from one brand to another, or as a second dose of this drug (e.g, capsules) without consulting your doctor or pharmacist. Your diet may have to be adjusted.

Missed Dose

If you miss a dose, remember it as soon as possible until it is within 4 hours of the next dose. In that case, leave the missed dose. Take your next dose at regular times. If you miss a dose of more than 2 consecutive days, then check with your doctor. Do not double the dose to catch up.


Store at room temperature away from light and moisture. Do not cool. Do not store in the bathroom. Keep all medications away from children and pets.

Until instructed not to do so, do not flush the medicines in the toilet and do not drain in the drain. When this period expires or does not need it, then properly release this product. Consult your pharmacist or local waste disposal company.

Disclaimer: DrLinex has made every effort to ensure that all information is factually accurate, comprehensive and up-to-date. However, this article should not be used as a licensed health care professional’s choice of knowledge and expertise. You should always consult your doctor or other health care professional before taking any medication. The information given here is subject to change and it has not been used to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions or adverse effects. The lack of warning or other information for any drug does not indicate that the combination of medicine or medication is safe, effective or appropriate for all patients or all specific uses.

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