Phenytoin capsules and extended-release capsules

What are phenytoin capsules and extended-release capsules?

PHENYTOIN (Dilantin® Kapseals®, Phenytek™) helps to control seizures (convulsions) in certain types of epilepsy. Phenytoin can help to prevent seizures occurring during or after surgery. Phenytoin also treats nerve-related pain such as trigeminal neuralgia. It is not for common aches and pains. Generic phenytoin capsules are available.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:

an alcohol abuse problem
blood disorders or disease
depression
diabetes
fever
heart problems
kidney disease
liver disease
porphyria
receiving intramuscular injections
receiving radiation therapy
skin problems
suicidal thoughts, plans, or attempt; a previous suicide attempt by you or a family member
thyroid disease
an unusual or allergic reaction to phenytoin, other medicines, foods, dyes, or preservatives
pregnant or trying to get pregnant
breast-feeding

How should I take this medicine?

Take phenytoin capsules by mouth. Follow the directions on the prescription label. Swallow the capsules with a drink of water. If you are taking extended-release capsules, swallow them whole; do not crush or chew. Take phenytoin with food if it upsets your stomach. It may be best to take your phenytoin capsules consistently with or without food. Take your doses at regular intervals. Do not take your medicine more often than directed.

What if I miss a dose?

Try not to miss a scheduled dosage, especially if you are taking phenytoin extended-release capsules just once per day. If you miss a dose, take it as soon as you can. If it is less than four hours to your next dose, take only that dose. If you only take a dose once a day and do not remember until the next day, skip the missed dose and resume your normal schedule. Do not take double or extra doses.

What drug(s) may interact with phenytoin?

Many medicines can interact with phenytoin; check with your prescriber or health care professional if you regularly take other medications or over-the-counter products. Some of the medicines that can interact with phenytoin are listed:

alcohol
amphetamines
antacids
aspirin and aspirin-like medicines
barbiturate medicines for inducing sleep or treating seizures (convulsions)
bosentan
calcium supplements
carbamazepine
cimetidine
ciprofloxacin
clopidogrel
cyclosporine
disulfiram
enteral feedings (liquid nutritional drinks or tube feeding liquids)
ethosuximide
felbamate
female hormones, including contraceptive or birth control pills
fluconazole
folic acid, vitamin B₉
heart medicines such as digoxin or digitoxin
chloramphenicol
corticosteroid hormones such as prednisone or cortisone
isoniazid
itraconazole
kava kava
ketoconazole
leucovorin
levodopa
lidocaine
medicines for hay fever and other allergies
medicines for mental depression, anxiety or other mood problems
medicines to control heart rhythm
medicines used to treat HIV infection or AIDS
methadone or other medicines for pain
methsuximide
modafinil
omeprazole
oxcarbazepine
rifampin, rifabutin or rifapentine
sevelamer
sirolimus
St. John's wort
sucralfate
tacrolimus
theophylline
tiagabine
ticlopidine
tramadol
valproic acid
voriconazole
warfarin
zonisamide

Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.

What should I watch for while taking phenytoin?

Visit your prescriber or health care professional for regular checks on your progress. Your prescriber or health care professional may schedule regular blood tests, because phenytoin therapy needs careful monitoring. Do not stop taking phenytoin suddenly.

If you take phenytoin for seizures, it is a good idea to carry an identification card, necklace or bracelet with details of your condition, medications and prescriber or health care professional.

Do not change brands or dosage forms of phenytoin without discussing the change with your prescriber or health care professional.

You may feel dizzy or drowsy. Do not drive, use machinery, or do anything that needs mental alertness until you know how phenytoin affects you. To reduce the risk of dizzy or fainting spells, do not sit or stand up quickly, especially if you are an older patient. Alcohol can make you more dizzy, increase flushing and rapid heartbeats. Avoid alcoholic drinks.

The use of this medicine may increase the chance of suicidal thoughts or actions. Pay special attention to how you are responding while on this medicine. Any worsening of mood, or thoughts of suicide or dying should be reported to your health care professional right away.

If you are going to have surgery, tell your prescriber or health care professional that you are taking phenytoin.

Birth control pills (contraceptive pills) may not work properly while you are taking phenytoin; talk with your prescriber about the use of other methods of birth control.

Phenytoin can cause unusual growth of gum tissues; visit your dentist regularly. Problems can arise if you need dental work, and in the day to day care of your teeth. Try to avoid damage to your teeth and gums when you brush or floss your teeth.

Do not take antacids at the same time as phenytoin. If you get an upset stomach and want to take an antacid or medicine for diarrhea, make sure there is an interval of 2 to 3 hours before or after you took phenytoin.

What side effects may I notice from taking phenytoin?

Side effects that you should report to your prescriber or health care professional as soon as possible:

chest pain or tightness; fast or irregular heartbeat (palpitations)
confusion, nervousness, hostility, or other behavioral changes (especially in children or elderly patients)
dark yellow or brown urine
difficulty breathing, wheezing or shortness of breath
double vision or uncontrollable and rapid eye movement
fainting spells or lightheadedness
fever, sore throat
headache
loss of seizure control
mouth ulcers
poor control of body movements or difficulty walking
redness, blistering, peeling or loosening of the skin, including inside the mouth
sexual problems (painful erections, loss of sexual desire)
skin rash, itching
stomach pain
swollen or painful glands
unusual bleeding or bruising, pinpoint red spots on skin
unusual tiredness or weakness
unusual swelling
vomiting
worsening of mood, thoughts or actions of suicide or dying
yellowing of the eyes or skin

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):

clumsiness or unsteadiness
constipation
difficulty sleeping
dizziness or drowsiness
excessive hair growth on the face or body
loss of appetite
nausea
stomach upset
unusual growth of gum tissue

Where can I keep my medicine?

Keep out of the reach of children in a container that small children cannot open.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Keep container tightly closed. Throw away any unused medicine after the expiration date.

Phenytoin chewable tablets

What are phenytoin chewable tablets?

PHENYTOIN (Dilantin® Infatabs®) helps to control seizures (convulsions) in certain types of epilepsy. Phenytoin can help to prevent seizures occurring during or after surgery. Phenytoin also treats nerve-related pain such as trigeminal neuralgia. It is not for common aches and pains. Generic phenytoin chewable tablets are not yet available.