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

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

kidney disease

liver disease

porphyria

suicidal thoughts, plans, or attempt; a previous suicide attempt by you or a family member

an unusual or allergic reaction to primidone, phenobarbital, other barbiturates or seizure medications, other medicines, foods, dyes, or preservatives

pregnant or trying to get pregnant

breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on the advice of your doctor or health care professional.
Contact your pediatrician or health care professional regarding the use of this medication in children. Special care may be needed. While this drug may be prescribed for children for selected conditions, precautions do apply.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

What if I miss a dose?

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 and skip the missed dose. Do not take double or extra doses.

What may interact with this medicine?

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

voriconazole

This medicine may also interact with the following medications:

cancer-treating medications

cyclosporine

disopyramide

doxycycline

female hormones, including contraceptive or birth control pills

medicines for mental depression, anxiety or other mood problems

medicines for treating HIV infection or AIDS

modafinil

prescription pain medications

quinidine

warfarin

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular checks on your progress. It may be 2 to 3 weeks before you see the full effects of this medicine. Do not suddenly stop taking this medicine, you may increase the risk of seizures. Your doctor or health care professional may want to gradually reduce the dose. Wear a medical identification bracelet or chain to say you have epilepsy, and carry a card that lists all your medications.
You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.
Birth control pills may not work properly while you are taking this medicine. Talk to your doctor about using an extra method of birth control.
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.

What side effects may I notice from receiving this medicine?

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

allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue

blurred, double vision, or uncontrollable rolling or movements of the eyes

redness, blistering, peeling or loosening of the skin, including inside the mouth

shortness of breath or difficulty breathing

unusual excitement or restlessness, more likely in children and the elderly

unusually weak or tired

worsening of mood, thoughts or actions of suicide or dying

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

clumsiness, unsteadiness, or a hang-over effect

decreased sexual ability

dizziness, drowsiness

loss of appetite

nausea or vomiting

Where should I keep my medicine?

Keep out of the reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.