Do not take this medication with any of the following:
-Voriconazole
This medication may also interact with the following:
-Antivirals for HIV or AIDS
-Cyclosporine
-Disopyramide
-Doxycycline
-Estrogen and progestin hormones
-Medications for cancer
-Medications for depression, anxiety, or other mental health conditions
-Modafinil
-Prescription pain medications
-Quinidine
-Warfarin

They need to know if you have any of these conditions:
-Kidney disease
-Liver disease
-Porphyria
-Suicidal thoughts, plans, or attempt by you or a family member
-An unusual or allergic reaction to primidone, phenobarbital, other barbiturates or seizure medications, other medications, foods, dyes, or preservatives
-Pregnant or trying to get pregnant
-Breast-feeding

Visit your care team for regular checks on your progress. It may be 2 to 3 weeks before you see the full effects of this medication.
Do not suddenly stop taking this medication. You may increase the risk of seizures. Your care team will tell you how much medication to take. If your care team wants you to stop the medication, the dose may be slowly lowered over time.
Wear a medical ID bracelet or chain to say you have epilepsy. Carry a card that describes your condition. List the medications and doses you take on the card.
This medication may affect your coordination, reaction time, or judgment. Do not drive or operate machinery until you know how this medication affects you. Sit up or stand slowly to reduce the risk of dizzy or fainting spells. Drinking alcohol with this medication can increase the risk of these side effects.
Estrogen and progestin hormones may not work as well while you are taking this medication. Your care team can help you find the contraceptive option that works for you.
This medication may cause thoughts of suicide or depression. This includes sudden changes in mood, behaviors, or thoughts. These changes can happen at any time but are more common in the beginning of treatment or after a change in dose. Call your care team right away if you experience these thoughts or worsening depression.
People who become pregnant while using this medication may enroll in the North American Antiepileptic Drug Pregnancy Registry by calling 1-888-233-2334. This registry collects information about the safety of antiepileptic medication use during pregnancy.
This medication may cause a decrease in vitamin D and folic acid. You should make sure that you get enough vitamins while you are taking this medication. Discuss the foods you eat and the vitamins you take with your care team.

Keep out of the reach of children and pets.
This medication may cause accidental overdose and death if it is taken by other adults, children, or pets. Mix any unused medication with a substance like cat litter or coffee grounds. Then throw the medication away in a sealed container like a sealed bag or a coffee can with a lid. Do not use the medication after the expiration date.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F).