To control certain types of seizures, primidone is used alone or in combination with other medications. Primidone belongs to the anticonvulsant medication class. It reduces abnormal electrical activity in the brain.

Primidone is available as an oral tablet. It is typically taken three to four times per day. Every day, take primidone at the same time(s). Follow the instructions on your prescription label exactly, and ask your doctor or pharmacist to explain any parts you don’t understand. Prednisone should be taken exactly as directed. Do not take more or less of it, or take it more frequently than your doctor has prescribed.

Your doctor will most likely start you on a low dose of primidone and gradually increase it, no more than once every three days. If you are already taking another medication to treat your seizures and your doctor wants you to start taking primidone, your doctor will gradually reduce your dose of the other medication while gradually increasing your dose of primidone over at least two weeks.

Primidone can help you manage your condition, but it will not cure it. You may not feel the full benefit of this medication for several weeks or longer. Even if you feel fine, keep taking primidone. Even if you experience unusual changes in behaviour or mood, do not stop taking primidone without first consulting your doctor. If you stop taking primidone abruptly, your seizures may worsen. Your doctor will most likely gradually reduce your dose.

Other uses for this medication may be prescribed. For more information, consult your doctor or pharmacist.

Before taking primidone,

• If you are allergic to primidone, phenobarbital, or any other medications, tell your doctor and pharmacist.
• Inform your doctor and pharmacist about any prescription and over-the-counter medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Make sure to include any of the following: Warfarin (Coumadin) is an anticoagulant (blood thinner); antidepressants; disulfiram (Antabuse); doxycycline (Vibramycin); griseofulvin (Grifulvin); anxiety, mental illness, and pain medications; other seizures medications such as oxcarbazepine (Trileptal), phenobarbital, phenytoin (Dilantin), and valproic acid (Depakene, Depakote); oral contraceptives (birth control pills); sedatives, sleeping pills, and tranquillizers, as well as oral steroids such as dexamethasone (Decadron, Dexone) and prednisone (Deltasone). Your doctor may need to adjust the doses of your medications or closely monitor you for side effects.
• Inform your doctor if you have or have 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).
• If you are pregnant or intend to become pregnant, inform your doctor. Call your doctor if you become pregnant while taking primidone.
• If you are breast-feeding, inform your doctor. If you breastfeed during treatment, your baby may be exposed to primidone through the breast milk. Keep a close eye on your baby for signs of drowsiness or poor weight gain.
• If you are having surgery, including dental surgery, inform your doctor or dentist that you are taking primidone.
• You should be aware that this medication may make you drowsy. Do not drive or operate machinery until you know how this medication affects you.
  Consult your doctor about the safe use of alcohol while taking this medication.
• You should be aware that while taking primidone, your mental health may change unexpectedly and you may become suicidal (thinking about harming or killing yourself, planning or attempting to do so). During clinical trials, a small number of adults and children aged 5 and up (about 1 in 500) who took anticonvulsants such as primidone to treat various conditions became suicidal. Some of these people began having suicidal thoughts and behaviours as soon as one week after starting the medication. There is a risk of experiencing changes in your mental health if you take an anticonvulsant medication like primidone, but there is also a risk of experiencing changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of using an anticonvulsant medication outweigh the risks of not using it. If you, your family, or your carer experience any of the following symptoms, you should contact your doctor right away: Panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behaviour; mania (frenzied, abnormally excited mood); talking or thinking about hurting yourself or ending your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behaviour or mood. Make sure your family or carer is aware of any potentially serious symptoms so that they can contact a doctor if you are unable to seek treatment on your own.

Continue to eat normally unless your doctor tells you otherwise.

As soon as you remember, take the missed dose. If the next dose is approaching, skip the missed dose and resume your regular dosing schedule. Do not take a double dose to compensate for a missed one.

Primidone may have unwanted side effects. If any of the following symptoms are severe or do not go away, contact your doctor:

• Tiredness that is excessive
• Dizziness
• Movement coordination is difficult.
• Nausea
• Vomiting
• Appetite loss
• Double vision
• Eye movements that are uncontrollable
• Sexual ability decline

Some of the side effects can be severe. Call your doctor right away if you experience any of the following symptoms:

• Rash

Other side effects of primidone are possible. If you experience any unusual side effects while taking this medication, contact your doctor.

If you have a serious side effect, you or your doctor can report it to the FDA’s MedWatch Adverse Event Reporting programme online or by phone (1-800-332-1088).

Keep this medication in its original container, tightly closed, and out of the reach of children. Keep it at room temperature and away from sources of extreme heat and moisture (not in the bathroom).

It is critical to keep all medication out of children’s sight and reach because many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and are easily opened by young children. To keep young children safe from poisoning, always lock the safety caps and immediately place the medication in a safe location out of their sight and reach. http://www.upandaway.org

Unwanted medications should be disposed of in a specific manner so that pets, children, and other people cannot consume them. You should not, however, flush this medication down the toilet. Instead, a medicine take-back programme is the best way to dispose of your medication. Learn about take-back programmes in your community by speaking with your pharmacist or contacting your local garbage/recycling department. If you do not have access to a take-back programme, visit the FDA’s Safe Disposal of Medicines website for more information.

In the event of an overdose, dial 1-800-222-1222 for poison control. There is also information available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, is having difficulty breathing, or cannot be awakened, dial 911 immediately.

Keep all of your doctor’s and laboratory appointments. Your doctor will order a series of laboratory tests to assess your response to primidone.

Do not give your medication to anyone else. If you have any questions about refilling your prescription, ask your pharmacist.

It is critical that you keep a written record of all prescription and nonprescription (over-the-counter) medications you are taking, as well as any vitamins, minerals, or other dietary supplements. You should bring this list with you whenever you go to the doctor or are admitted to the hospital. It is also important to have this information on hand in case of an emergency.