Generic name: primidone (PRIM i done)
Brand name: Mysoline
Dosage forms: oral tablet (250 mg; 50 mg)
Drug class: Barbiturate anticonvulsants
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.
Before taking this medicine
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:
- 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.
How should I take primidone?
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.
What happens if I miss a dose?
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.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking primidone?
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.
Primidone 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.
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 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.
What other drugs will affect primidone?
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.