Mysoline Side Effects
Generic name: primidone
Note: This document contains side effect information about primidone. Some of the dosage forms listed on this page may not apply to the brand name Mysoline.
Some side effects of Mysoline may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to primidone: oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking primidone (the active ingredient contained in Mysoline) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any new or worsening symptoms 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 any of these serious side effects:
loss of balance or coordination;
easy bruising or bleeding; or
Less serious side effects of primidone may include:
dizziness, drowsiness, spinning sensation;
nausea, vomiting, loss of appetite;
mild skin rash; or
impotence, loss of interest in sex.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.
For Healthcare Professionals
Applies to primidone: oral suspension, oral tablet
Nervous system effects including ataxia and vertigo have been reported most frequently.
Ataxia and vertigo tend to disappear either with continued therapy or with the reduction of the initial dosage.
Gastrointestinal effects including nausea, anorexia, and vomiting have been reported occasionally.
General effects including fatigue, hyperirritability, and drowsiness have been reported occasionally.
Psychiatric effects including emotional disturbances have been reported occasionally. A case of primidone (the active ingredient contained in Mysoline) induced catatonic schizophrenia has also been reported.
Massive crystalluria has also been rarely been reported following acute overdoses of primidone (the active ingredient contained in Mysoline)
Genitourinary effects including sexual impotency have been reported occasionally. A case of massive crystalluria has been reported in a patient receiving maintenance doses of primidone.
Ocular effects including diplopia and nystagmus have been reported occasionally.
Dermatologic effects including morbilliform skin eruptions have been reported occasionally.
Hematologic effects including granulocytopenia, agranulocytosis, red cell hypoplasia, thrombocytopenia, and aplasia have been reported rarely. The manufacturer has reported that megaloblastic anemia may occur as a rare idiosyncrasy to primidone (the active ingredient contained in Mysoline)
The anemia may respond to folic acid without the necessity to discontinue the primidone. The phenobarbital metabolite of primidone has been reported to have potentiated porphyrias.
Rheumatologic side effects include drug induced lupus, frozen shoulder, and Dupuytren's contractures.
More Mysoline resources
- Mysoline Prescribing Information (FDA)
- Mysoline MedFacts Consumer Leaflet (Wolters Kluwer)
- Mysoline Concise Consumer Information (Cerner Multum)
- Mysoline Advanced Consumer (Micromedex) - Includes Dosage Information
- Mysoline Monograph (AHFS DI)
- Primidone Prescribing Information (FDA)
- Primidone Professional Patient Advice (Wolters Kluwer)
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