It is very important that your doctor check your progress at regular visits while you are using this medicine to see if it is working properly and to allow for a change in the dose. Blood tests may be needed to check for any unwanted effects.
Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
Do not use this medicine if you or your child are also using delavirdine (Rescriptor®). Using these medicines together may cause unwanted effects.
Lymph node problems may occur while using this medicine. Check with your doctor right away if you or your child have swollen, painful, or tender lymph glands in your neck, armpit, or groin.
Do not stop taking this medicine without first checking with your doctor. Your doctor may want you or your child to gradually reduce the amount you are using before stopping completely.
If you or your child develop a skin rash, hives, or any allergic reaction to this medicine, stop taking the medicine and check with your doctor as soon as possible.
Tell your doctor right away if you or your child develop a fever; rash; swollen, painful, or tender lymph glands in the neck, armpit, or groin; unusual bleeding or bruising; or yellow eyes or skin after receiving this medicine. These may be symptoms of a serious and life-threatening condition called Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).
Phenytoin can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:
- If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
- Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in urine or stools; or pinpoint red spots on your skin.
- Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
- Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
- Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
- Avoid contact sports or other situations where bruising or injury could occur.
This medicine may decrease bone mineral density. A low bone mineral density can cause weak bones or osteoporosis. If you or your child have any questions about this ask your doctor.
This medicine may affect blood sugar levels. If you or your child notice a change in the results of your blood or urine sugar tests or if you have any questions, check with your doctor.
This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you, your child, or your caregiver notice any of these side effects, tell your or your child's doctor right away.
In some patients (usually younger patients), tenderness, swelling, or bleeding of the gums (gingival hyperplasia) may appear soon after phenytoin treatment is started. To help prevent this, brush and floss your teeth carefully and regularly and massage your gums. Also, see your dentist every 6 months to have your teeth cleaned. If you have any questions about how to take care of your teeth and gums, or if you notice any tenderness, swelling, or bleeding of your gums, check with your doctor or dentist.
Before you have any medical tests, tell the medical doctor in charge that you or your child are taking this medicine. The results of some tests may be affected by this medicine.
This medicine may cause drowsiness, trouble in thinking, or trouble in controlling movements. Make sure you know how you react to this medicine before you drive, use machines, or do other jobs that require you to be alert, well-coordinated, or able to think or see well.
Avoid drinking alcohol while you are receiving this medicine.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.