Generic name: Primidone.

Other brand names: Myidone, Sertan.

Mysoline is an anticonvulsant. It acts as a central nervous system depressant. 

Quick Facts About Mysoline


Used to treat epileptic and other seizures.

Mysoline Dosage

Take exactly as prescribed. Do not change brands unless directed by your doctor. Should not stop abruptly; may cause seizures. If using suspension form, shake well before each use. May take several weeks to observe full effects of medication.

  • Usual adult dose: for children 8 years and older and adults who are being treated for the first time — Day 1 to Day 3—100 to 125 milligrams at bedtime. Day 4 to Day 6 — 100 to 125 milligrams taken 2 times per day. Day 7 to Day 9 — 100 to 125 milligrams taken 3 times per day. Day 10 to maintenance — 250 milligrams taken 3 to 4 times per day. For patients already using anticonvulsants — starting dose of 100 to 125 milligrams at bedtime, and gradually increased to a maintenance level.
  • Usual child dose: for children under 8 years — Day 1 to Day 3 — 50 milligrams at bedtime. Day 4 to Day 6 — 50 milligrams taken 2 times per day. Day 7 to Day 9 — 100 milligrams taken 2 times per day. Day 10 to maintenance — 125 to 150 milligrams taken 3 times per day, up to 250 milligrams taken 3 times per day, or 10 to 25 milligrams per 2.2 pounds of body weight per day.
  • Missed dose: take as soon as possible, unless within 1 hour of next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Mysoline Side Effects

Overdose symptoms:

no specific information available. However, if you suspect an overdose, immediately seek medical attention.

More common side effects: lack of muscle coordination, vertigo.

Less common Mysoline side effects: double vision, drowsiness, emotional disturbances, excessive irritability, fatigue, impotence, loss of appetite, nausea, skin eruptions resembling measles, uncontrolled eyeball movements, vomiting.


Inform your doctor before combining Mysoline with:

blood thinners such as Coumadin; doxycycline (Doryx or Vibramycin); estrogen-containing oral contraceptives such as Ortho-Novum and Triphasil; griseofulvin (Fulvisin-U/F or Grifulvin V); MAO inhibitors such as Nardil and Parnate; steroid medications such as Decadron.

Avoid alcohol during Mysoline therapy. 

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Increased risk of birth defects in infants bom to epileptic women taking anticonvulsants. Appears in breast milk; could affect a nursing infant.

No special precautions apply to seniors.

Follow doctor’s instructions carefully for children.

  • Should not take if you have porphyria (inherited metabolic disorder), or if you are sensitive to or allergic to phenobarbital.
  • Doctor should check your blood count every 6 months.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Mysoline side effects, please contact your healthcare provider.