Primidone Brand names of primidone Prior to taking primidone let your health care provider know Usage How to use primidone How primidone works Side effects Possible interactions Discontinuation Storage instructions


Brand names of primidone

  • Apo-Primidone
  • Myidone
  • Mysoline
  • PMS-Primidone
  • Sertan

Primidone, an anticonvulsant, belongs to the pyrimidinedione class. Phenobarbital (major) and phenylethylmalonamide (PEMA) (minor) are active metabolites of this class of anticonvulsants. Primidone is mainly used to treat complex partial, simple partials, generalized tonic-clonic seizures, and myoclonic, akinetic seizures. This anticonvulsant, since the 1980's, has been used to treat essential tremor, as an alternative to propranolol. Primidone, unlike anticonvulsants like carbamazepine and valproic acid, is not the preferred medicine to treat bipolar disorder or any other psychiatric issue. Additionally, it is not a prescribed widely to treat neuropathic pain, trigeminal neuralgia, or migraine. Sometimes, however, Primidone is used for the treatment of long QT syndrome, cerebral palsy, and athetosis.

At one point of time, this medicine was a crucial part in the treatment of partial and generalized seizures. It, in combination with phenytoin, was also commonly used for secondarily generalized seizures originating in the temporal lobes. The early 1980's witnessed the growing popularity of carbamazepine over Primidone, as the latter had higher incidence of sedation. With time, more and more anticonvulsants hit the market, leading to a decline in popularity of Primidone. As a result, major Western pharmaceutical players withdrew from the manufacture and sale of this medicine. In the developed world, Primidone has become an almost obsolete medicine, thanks to the availability of a large number of anticonvulsants.

Primidone differs from other anticonvulsants as it interacts with voltage-gated sodium channels that curb high-frequency insistent firing of action potentials. Compared to phenobarbital, it is less harmful in overdose. Primidone, like carbamazepine, phenobarbital, and phenytoin, induces metabolic enzymes in the liver, thereby accelerating the metabolism of other medicines. Like anticonvulsants of the pre-1989 era, Primidone has been linked with hyperhomocysteinemia, folate deficiency and its various symptoms (birth defects, depression, and megaloblastic anemia), reduced calcium absorption, and various bone-related diseases. In addition, Primidone has an inclination to induce sedation, like other anticonvulsants.

Prior to taking primidone let your health care provider know

  • If you have allergy to primidone, phenobarbital or other medicines.
  • The prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you consume, or intend to consume. Ensure that you highlight the following: anticoagulants ('blood thinners') such as warfarin (Coumadin); antidepressants; disulfiram (Antabuse); doxycycline (Vibramycin); griseofulvin (Grifulvin); medications for anxiety, mental illness, and pain; other medications for seizures such as oxcarbazepine (Trileptal), phenobarbital, phenytoin (Dilantin), and valproic acid (Depakene, Depakote); oral contraceptives (birth control pills); oral steroids such as dexamethasone (Decadron, Dexone) and prednisone (Deltasone); sedatives; sleeping pills; and tranquilizers. The doctor might alter the doses of your medicines, or monitor you to observe side effects, if any.
  • If you are suffering with, or have a family history of porphyria (a disease that results in the accumulation of some natural substances causing stomach pain, alters thinking and behavior, or other symptoms).
  • If you are an expecting mother, intend to conceive, or are breast-feeding. You should consult your doctor if you become pregnant while consuming primidone. Also, if your child feels drowsiness when you breastfeed, call your doctor.
  • If you have undergone, or intend to undergo surgery of any kind including dental surgery, you should inform your doctor or dentist that you are consuming primidone.
  • Primidone sometimes causes drowsiness. Therefore, you should refrain from driving or operating machines, until you know how your body responds to this medicine.
  • You can also consult your doctor regarding the safe use of alcohol while consuming Primidone.
  • Changes in thinking (mental health), and development of suicidal tendencies (tendency to harm/kill yourself, or intention to do these) might occur due to Primidone consumption. Clinical studies have revealed that some adults, and children of age 5 and above (1 in 500) show suicidal tendencies on consumption of anticonvulsants such as Primidone. Some of these patients started showing suicidal tendencies even during the first week of Primidone consumption. Changes in mental health are also evident due to consumption of Primidone. However, if your condition is not dealt with, alteration is mental health can occur. Whether to take the anticonvulsant or not (considering the risks involved), has to be decided by you and your doctor. Development of symptoms such as panic attacks, agitation or restlessness; irritability, anxiety, or depression; impulsiveness; insomnia; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); suicidal tendencies; withdrawal from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood calls for immediate attention of your doctor. Your family members should be able to analyze the seriousness of the symptoms, and call the doctor, if you are unable to call the doctor on your own.


To check epilepsy related seizures. By checking and lessening the intensity of seizures, you can lead a better life. Also, it reduces the risks that may arise when you lose consciousness, and minimizes the possibility of frequent, repeated seizures. Primidone, that falls under the class barbiturate anticonvulsants, checks the abnormal electrical activity associated with the human brain because of a seizure.

How to use primidone

Primidone should be taken orally, 3-4 times a day, with food (if it causes stomach upset) or without food, or as suggested by your doctor. To prevent side effects such as drowsiness and dizziness, your doctor may prescribe this medicine at a low dose before going to bed, and increase the dosage gradually. In case you have been using some other anticonvulsant, your doctor may ask you to continue taking that medication, and gradually lessen the dosage when you start taking Primidone. You should abide by the doctor's instructions. The dosage of Primidone is based on your medical health, blood levels of primidone, use of other medications to treat seizures, and response to treatment. You must give a few weeks to find the best dose for your health. When this drug is administered in such a way that its level is constant in your body, it yields maximum benefit. Hence, you should consume this drug at evenly distributed intervals. Therefore, you should take this medication at the same time every day. Primidone or any other anticonvulsant should not be taken without medical prescription. Sudden withdrawal of Primidone may worsen the seizure, or result in difficult-to-treat seizure (status epilepticus). Withdrawal symptoms has been associated with Primidone, especially when the patient has been a regular user of the medication, or if the medication has been administered in high doses. Such symptoms like anxiety, hallucinations, twitching, trouble sleeping may develop if the medication is stopped suddenly. This can also lead to severe seizures, and sometimes death. To prevent these symptoms, your doctor may lessen your dosage slowly. You should report withdrawal symptoms to your doctor immediately. Addiction to drugs is also a side effect of primidone. This side effect may intensify if you have had a drug (or alcohol) abuse history. Primidone should be consumed at the prescribed timing. Your doctor should be immediately notified if the seizure control worsens.

How primidone works

Primidone is believed to lower the brain activity (in some areas), and inhibit abnormal neuron firing that results in seizures.

Side effects

  • sore throat
  • red or purple point like rash on the skin or mucous membranes
  • mouth sores
  • paleness
  • confusion
  • fever
  • swollen glands
  • blistering or peeling skin lesions
  • easy bruising
  • weakness
  • lethargy or seizures may be a sign of a potentially fatal blood reaction or other complication
Less common

Possible interactions

Other medicaments:
15% of primidone converts into phenobarbital after consumption. To understand possible interactions of this medication with other medicines, you can read the profile of this anticonvulsant.
Herbal medicines or minerals:
Drowsiness may develop due to interaction with Valerian and kava kava. Likewise, kola or ma huang may interact to cause abnormal stimulation of the central nervous system. This can also lead to increase in calcium and vitamin D. Consult your doctor to know more about calcium, vitamin D and K and folic acid supplements.
The sedative and depressant effects of Primidone on the on brain function can increase due to alcohol consumption.
Tobacco smoking:
May accelerate the sedative effects of Primidone.
Occurrence of unrelated illness:
Consult your doctor pertaining to any illness or injury that may prevents the use of Primidone based on your regular dose schedule.


You must not discontinue Primidone without your doctor's consent as this may cause severe and repeated seizures.

Storage instructions

This medication should be stored 68-77 degrees F (25 degrees C) in a dry place, away from direct light. This medicament should not be stored in the bathroom. Also, it should be kept away from kids and pets. Unless otherwise mentioned, you must not flush the medications down the urinal or the drain. If you do not need the product anymore, or if the medication has reached its expiry date, you should discard it in a proper manner. You can also talk to your pharmacist or your local waste disposal organization to learn about the correct ways to discard your product.

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