Do not take this medicine with any of the following medications:

-certain medicines used to treat HIV infection or AIDS that are given in combination with cobicistat
-
delavirdine


-
ibrutinib


-
ranolazine



This medicine may also interact with the following medications:

-
albendazole


-
alcohol


-
-
aspirin and aspirin-like medicines


-
certain medicines for blood pressure like nifedipine, nimodipine, and verapamil


-
certain medicines for cancer


-
certain medicines for cholesterol like atorvastatin, simvastatin, and fluvastatin


-
certain medicines for depression, anxiety, or psychotic disturbances


-
certain medicines for fungal infections like ketoconazole and itraconazole


-
certain medicines for irregular heart beat like amiodarone and quinidine


-
certain medicines for seizures like carbamazepine, phenobarbital, and topiramate


-
certain medicines for stomach problems like cimetidine and omeprazole


-
chloramphenicol


-
cyclosporine


-
diazoxide


-
digoxin


-
disulfiram


-
doxycycline


-
female hormones, like estrogens and birth control pills


-
furosemide


-
halothane


-
isoniazid


-
medicines that relax muscles for surgery


-medicines used to treat HIV infection or AIDS
-
methylphenidate


-
narcotic medicines for pain


-
phenothiazines like chlorpromazine, mesoridazine, prochlorperazine, thioridazine


-
praziquantel


-
reserpine


-
rifampin


-
St. John''s Wort


-
steroid medicines like prednisone or cortisone


-
sulfonamides like sulfamethoxazole or sulfasalazine


-
supplements like folic acid or vitamin D


-
theophylline


-
ticlopidine


-
tolbutamide


-
warfarin

They need to know if you have any of these conditions:
-an alcohol abuse problem
-Asian ancestry
-blood disorders or disease
-heart disease, low blood pressure
-kidney disease
-liver disease
-suicidal thoughts, plans, or attempt; a previous suicide attempt by you or a family member
-an unusual or allergic reaction to phenytoin, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

Visit your doctor or health care provider for regular checks on your progress. Your doctor or health care provider may schedule regular blood tests, because this medicine needs careful monitoring. Do not stop using this medicine suddenly. This increases the risk of seizures. Because your condition and the use of this medicine carry some risk, it is a good idea to carry an identification card, necklace or bracelet with details of your condition, medications and doctor or health care provider.

This medicine may cause serious skin reactions. They can happen weeks to months after starting the medicine. Contact your health care provider right away if you notice fevers or flu-like symptoms with a rash. The rash may be red or purple and then turn into blisters or peeling of the skin. Or, you might notice a red rash with swelling of the face, lips or lymph nodes in your neck or under your arms.

You may feel dizzy or drowsy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine 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 may cause rapid heartbeats. Avoid alcoholic drinks.

This medicine 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.

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 provider right away.

This medicine may cause a decrease in folic acid. You should make sure that you get enough folic acid while you are taking this medicine. Discuss the foods you eat and the vitamins you take with your health care provider.

This drug is given in a hospital or clinic and will not be stored at home.