Primidone is an anticonvulsant medicine that is used to control seizures.

Primidone may also be used for purposes not listed in this medication guide.

Some people have thoughts about suicide while taking primidone. Stay alert to changes in your mood or symptoms. Report any new or worsening symptoms to your doctor.

Do not stop using primidone suddenly, even if you feel fine. Stopping suddenly may cause increased seizures.

Primidone comes as a tablet to take by mouth. It is usually taken 3 to 4 times a day. Take primidone at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take primidone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of primidone and gradually increase your dose, not more often than once every 3 days. If you are taking another medication to treat your seizures and your doctor wants you to begin taking primidone instead, your doctor will gradually decrease your dose of the other medication and increase your dose of primidone over a period of at least 2 weeks.

Primidone may help control your condition but will not cure it. It may take several weeks or longer for you to feel the full benefit of this medication. Continue to take primidone even if you feel well. Do not stop taking primidone without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood. If you suddenly stop taking primidone, your seizures may become worse. Your doctor will probably decrease your dose gradually.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

If you are switching to primidone from another seizure medication, you may need to start taking primidone only at bedtime. Follow your doctor's instructions.

Do not stop using primidone suddenly, even if you feel fine. Stopping suddenly may cause increased seizures. Follow your doctor's instructions about tapering your dose.

It may take several weeks before you receive the full benefit of taking primidone. Your doctor will determine how long to treat you with this medicine.

If you use this medicine long-term, you may need frequent medical tests.

Store primidone at room temperature away from moisture, light, and heat.

In case of emergency, wear or carry medical identification to let others know you take seizure medication.

You should not use primidone if you are allergic to primidone or phenobarbital, or if you have:

• porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system).

Tell your doctor if you have ever had:

• depression;

• a mood disorder; or

• suicidal thoughts or actions.

Some people have thoughts about suicide while taking primidone. Your doctor will need to check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Do not start or stop taking seizure medication during pregnancy without your doctor's advice. Having a seizure during pregnancy could harm both mother and baby. Tell your doctor right away if you become pregnant.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of primidone on the baby. Be sure to tell the doctor who delivers your baby about your primidone use. Both you and the baby may need to receive medications to prevent excessive bleeding during delivery and just after birth.

Stop breast-feeding if you notice unusual drowsiness in the nursing baby. Talk with your doctor about how best to feed your baby while taking primidone.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Avoid driving or hazardous activity until you know how primidone will affect you. Your reactions could be impaired.

Drinking alcohol with this medicine can increase side effects.

Get emergency medical help if you have signs of an allergic reaction: hives, mouth sores, skin rash with blistering and peeling; difficult breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, depression, anxiety, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.

Primidone may cause serious side effects. Call your doctor at once if you have:

• unusual thoughts or behavior;

• loss of balance or coordination;

• fever, chills, sore throat;

• easy bruising or bleeding; or

• pale skin, unusual tiredness.

Common side effects of primidone may include:

• dizziness, drowsiness, spinning sensation;

• problems with balance or muscle movement;

• nausea, vomiting, loss of appetite;

• feeling tired or irritable;

• blurred vision;

• rash; or

• impotence, sexual problems.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Using primidone with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Other drugs may affect primidone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to primidone.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.