Primidone

Desoxyphenobarbital, Primaclone

WHY is this medicine prescribed?

Primidone is used alone or with other medications to control certain types of seizures. Primidone is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.

HOW should this medicine be used?

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.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking primidone,

• tell your doctor and pharmacist if you are allergic to primidone, phenobarbital or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while taking primidone. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had porphyria (condition in which certain natural substances build up in the body and may cause stomach pain, changes in thinking and behavior, or other symptoms).
• tell your doctor if you are pregnant or plan to become pregnant. If you become pregnant while taking primidone, call your doctor.
• tell your doctor if you are breast-feeding. If you breast-feed during your treatment, your baby may receive some primidone in the breast milk. Watch your baby closely for drowsiness or poor weight gain.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking primidone.
• you should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
• talk to your doctor about the safe use of alcohol while you are taking this medication.
• you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking primidone. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants such as primidone to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as one week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsant medication such as primidone, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling asleep or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); talking or thinking about wanting to hurt yourself or to end your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

What SPECIAL DIETARY instructions should I follow?

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

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for the missed one.

What SIDE EFFECTS can this medicine cause?

Primidone may cause side effects. Call your doctor if any of these symptoms are severe or do not go away:

• excessive tiredness
• dizziness
• difficulty coordinating movements
• nausea
• vomiting
• loss of appetite
• double vision
• uncontrollable eye movements
• decrease in sexual ability

Some side effects can be serious. If you experience the following symptom, call your doctor immediately:

• rash

Primidone may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

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. https://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 (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What OTHER INFORMATION should I know?

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.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: May 15, 2020.