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Primidone (Oral route)

Pronunciation:

PRIM-i-done

Brand Names:

  • Mysoline

Dosage Forms:

  • Tablet
  • Suspension

Classifications:

Therapeutic—

Anticonvulsant

Pharmacologic—

Barbiturate, Intermediate Acting

Uses of This Medicine:

Primidone is used alone or in combination with other medicines, to control seizures (convulsions) in the treatment of epilepsy. This medicine is an anticonvulsant that works in the brain tissue to stop seizures.

This medicine is available only with your doctor's prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, primidone is used in certain patients with the following medical conditions:

  • Essential tremor.

Before Using This Medicine:

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies—

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children—

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of primidone in children.

Older adults—

No information is available on the relationship of age to the effects of primidone in geriatric patients.

Unusual excitement or restlessness may occur in elderly patients, who are usually more sensitive than younger adults to these effects of primidone.

Pregnancy—

Pregnancy CategoryExplanation
All TrimestersDStudies in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy in a life threatening situation or a serious disease, may outweigh the potential risk.

Breast-feeding—

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Other medicines—

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Amifampridine
  • Artemether
  • Atazanavir
  • Boceprevir
  • Cobicistat
  • Daclatasvir
  • Darunavir
  • Delamanid
  • Delavirdine
  • Lopinavir
  • Lumefantrine
  • Lurasidone
  • Maraviroc
  • Nisoldipine
  • Rilpivirine
  • Ritonavir
  • Telaprevir
  • Tipranavir
  • Voriconazole

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Abiraterone Acetate
  • Adinazolam
  • Afatinib
  • Alfentanil
  • Alprazolam
  • Amiodarone
  • Amlodipine
  • Amobarbital
  • Amprenavir
  • Anisindione
  • Apixaban
  • Apremilast
  • Aprepitant
  • Aprobarbital
  • Aripiprazole
  • Astemizole
  • Atorvastatin
  • Bedaquiline
  • Bosutinib
  • Brentuximab Vedotin
  • Bromazepam
  • Bromocriptine
  • Brotizolam
  • Budesonide
  • Buprenorphine
  • Buspirone
  • Butabarbital
  • Butalbital
  • Cabazitaxel
  • Cabozantinib
  • Carbamazepine
  • Carisoprodol
  • Ceritinib
  • Chloral Hydrate
  • Chlordiazepoxide
  • Chlorzoxazone
  • Cilostazol
  • Cisapride
  • Citalopram
  • Clarithromycin
  • Clobazam
  • Clonazepam
  • Clorazepate
  • Conivaptan
  • Crizotinib
  • Cyclosporine
  • Dabigatran Etexilate
  • Dabrafenib
  • Dantrolene
  • Darifenacin
  • Dasatinib
  • Dexamethasone
  • Diazepam
  • Dicumarol
  • Dihydroergotamine
  • Docetaxel
  • Dolutegravir
  • Dronedarone
  • Dutasteride
  • Eletriptan
  • Eliglustat
  • Elvitegravir
  • Enzalutamide
  • Eplerenone
  • Ergotamine
  • Erlotinib
  • Erythromycin
  • Eslicarbazepine Acetate
  • Estazolam
  • Estradiol
  • Ethchlorvynol
  • Everolimus
  • Exemestane
  • Felodipine
  • Fentanyl
  • Flunitrazepam
  • Flurazepam
  • Fluticasone
  • Halazepam
  • Haloperidol
  • Ibrutinib
  • Idelalisib
  • Iloperidone
  • Imatinib
  • Indacaterol
  • Indinavir
  • Itraconazole
  • Ivabradine
  • Ketazolam
  • Ketoconazole
  • Ledipasvir
  • Lorazepam
  • Lormetazepam
  • Losartan
  • Lovastatin
  • Macitentan
  • Medazepam
  • Mephenesin
  • Mephobarbital
  • Meprobamate
  • Metaxalone
  • Methocarbamol
  • Methohexital
  • Midazolam
  • Morphine
  • Morphine Sulfate Liposome
  • Nateglinide
  • Nelfinavir
  • Netupitant
  • Nifedipine
  • Nilotinib
  • Nintedanib
  • Nitrazepam
  • Nordazepam
  • Ondansetron
  • Orlistat
  • Oxazepam
  • Oxymorphone
  • Paclitaxel
  • Pazopanib
  • Pentobarbital
  • Perampanel
  • Phenindione
  • Phenobarbital
  • Phenprocoumon
  • Pimozide
  • Piperaquine
  • Pixantrone
  • Pomalidomide
  • Ponatinib
  • Prazepam
  • Primidone
  • Propafenone
  • Quazepam
  • Quetiapine
  • Quinidine
  • Quinine
  • Regorafenib
  • Rifabutin
  • Rivaroxaban
  • Roflumilast
  • Romidepsin
  • Salmeterol
  • Saquinavir
  • Saxagliptin
  • Secobarbital
  • Sildenafil
  • Simeprevir
  • Simvastatin
  • Sirolimus
  • Sodium Oxybate
  • Sofosbuvir
  • Sorafenib
  • Sunitinib
  • Suvorexant
  • Tacrolimus
  • Tamoxifen
  • Tamsulosin
  • Tapentadol
  • Tasimelteon
  • Telithromycin
  • Temazepam
  • Temsirolimus
  • Terfenadine
  • Thiopental
  • Ticagrelor
  • Tofacitinib
  • Tolvaptan
  • Trabectedin
  • Tramadol
  • Trazodone
  • Triazolam
  • Ulipristal Acetate
  • Valproic Acid
  • Vandetanib
  • Vardenafil
  • Vemurafenib
  • Verapamil
  • Vilazodone
  • Vincristine Sulfate
  • Vincristine Sulfate Liposome
  • Vinflunine
  • Vorapaxar
  • Vortioxetine
  • Zaleplon
  • Zileuton
  • Ziprasidone
  • Zolpidem

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Betamethasone
  • Cannabis
  • Carbamazepine
  • Cortisone
  • Desogestrel
  • Dienogest
  • Drospirenone
  • Estradiol Cypionate
  • Estradiol Valerate
  • Ethinyl Estradiol
  • Ethynodiol Diacetate
  • Etonogestrel
  • Ginkgo
  • Hydrocortisone
  • Lamotrigine
  • Leucovorin
  • Levonorgestrel
  • Medroxyprogesterone Acetate
  • Mestranol
  • Methylprednisolone
  • Norelgestromin
  • Norethindrone
  • Norgestimate
  • Norgestrel
  • Ospemifene
  • Prednisolone
  • Prednisone
  • Rufinamide
  • Tiagabine
  • Triamcinolone
  • Warfarin

Other interactions—

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Ethanol

Other medical problems—

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Asthma, emphysema, or chronic lung disease—Primidone may cause serious problems in breathing.
  • Depression, history of or
  • Hyperactivity (in children) or
  • Kidney disease or
  • Liver disease—Primidone may make these conditions worse.
  • Porphyria (an enzyme problem)—Should not be used in patients with this condition.

Proper Use of This Medicine:

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine may be used with other seizure medicines. Keep using all of your seizure medicines unless your doctor tells you to stop.

Take primidone everyday in regularly spaced doses as ordered by your doctor. This will provide the proper amount of medicine needed to prevent seizures.

Dosing—

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (chewable tablets, suspension, or tablets):
    • For seizures:
      • Adults, teenagers, and children 8 years of age or older—At first, 100 or 125 milligrams (mg) once a day at bedtime. Your doctor may increase your dose if needed. However, the dose is usually not more than 2000 mg a day.
      • Children up to 8 years of age—At first, 50 mg once a day at bedtime. Your doctor may increase your dose if needed.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions While Using This Medicine:

It is very important that your doctor check your progress at regular visits while you are using this medicine to see if it is working properly and to allow for a change in the dose. Blood tests may be needed to check for any unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away. Your doctor may want you to join a pregnancy registry for patients taking a seizure medicine.

If you have been taking primidone regularly for several weeks, you should not suddenly stop taking it without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping completely.

This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you, your child, or your caregiver notice any of these side effects, tell your doctor or your child's doctor right away.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests (such as the metyrapone and phentolamine tests) may be affected by this medicine.

Before having any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are using this medicine.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for allergies or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; medicine for seizures or barbiturates; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

Primidone may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Even if taken at bedtime, it may cause some people to feel drowsy or less alert on arising. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

Oral contraceptives (birth control pills) containing estrogen may not work properly if you take them while you are taking primidone. Unplanned pregnancies may occur. You should use a different or additional means of birth control while you are taking primidone. If you have any questions about this, check with your doctor.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common
Shakiness and unsteady walk
unsteadiness, trembling, or other problems with muscle control or coordination
Less common
Unusual excitement or restlessness (especially in children and in the elderly)
Rare
Chills
cough or hoarseness
fainting spells
fever and sore throat
fever with or without chills
general feeling of tiredness or weakness
irregular heartbeat
lower back or side pain
painful or difficult urination
pale skin
shortness of breath
skin rash
sores, ulcers, or white spots on the lips or in the mouth
unusual bleeding or bruising
unusual tiredness or weakness

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose
Confusion
continuous, uncontrolled rolling eye movements
double vision
troubled breathing

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
Clumsiness or unsteadiness
dizziness or lightheadedness
feeling of constant movement of self or surroundings
sensation of spinning
Less common
Decreased sexual ability
drowsiness
loss of appetite
mood or mental changes
nausea or vomiting

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


Last Updated: 11/4/2014

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