Primidone (Mysoline) Uses

Primidone is used alone or with other antiepileptic medications to treat generalized tonic-clonic seizures (grand mal seizures), complex partial seizures (psychomotor seizures), and partial seizures (focal seizures).

There may be other uses of primidone—your health system pharmacists or healthcare professionals can give you further drug information.

Primidone (Mysoline) Mechanism of Action

Primidone works by decreasing abnormal electrical activity in the brain.

Primidone (Mysoline) Doses

Primidone comes in 50 mg, 125 mg, and 250 mg tablets to take by mouth. 

The usual dose for adults and children 8 years of age and older is as follows:

Days 1 through 3: Primidone 100 mg to 125 mg at bedtime.

Days 4 through 6: Primidone 100 mg to 125 mg twice a day.

Days 7 through 9: Primidone 100 mg to 125 mg three times a day.

Day 10 onwards: Maintenance dose of primidone 250 mg three to four times a day.

The maximum dose is 500 mg, taken four times a day.

The usual dose for children under 8 years of age is as follows:

Days 1 through 3: Primidone 50 mg at bedtime.

Days 4 through 6: Primidone 50 mg twice a day.

Days 7 through 9: Primidone 100 mg twice a day.

Day 10 onwards: Maintenance dose of primidone 125 mg to 250 mg three times a day.

Your doctor may check serum primidone levels (drug levels in your blood) and adjust the dose for optimum response. The clinically effective serum level of primidone is 5 to 12 mcg/mL.