Primidone

Primidone

Primidone is an aromatic anticonvulsant used to treat complex, partial and generalized seizures. 

Liver safety of Primidone

Therapy with primidone can be associated with increases in gamma glutamyltranspeptidase levels, but is not associated with serum aminotransferase elevations, and despite its similarity in structure to phenobarbital and phenytoin, clinically apparent liver injury from primidone has not been reported and must be exceedingly rare if it occurs at all.

Mechanism of action of Primidone

Primidone (prim' i done) is a pyrimidinedione anticonvulsant and is partially metabolized to phenobarbital.  Primidone is effective in suppressing seizure activity, but its mechanism of action is not well defined.  It is believed to work centrally via interactions with voltage-gated sodium channels inhibiting repetitive firing of action potentials. 

FDA approval information for Primidone

Primidone was approved for use in epilepsy in the United States in 1954.  For many years, primidone was considered a first line anticonvulsant agent, but it has been largely replaced by more recently developed anticonvulsants that are better tolerated, less sedative and have fewer long term adverse side effects.  Primidone has also been used to treat essential tremor. 

Dosage and administration for Primidone

Primidone is available as tablets of 50 and 250 mg in several generic formulations and under the brand names Mysoline, Myidone, Sertan and Apo-Primidone.  The recommended initial dose for adults is 100 to 125 mg daily, increasing slowly to a maintenance dose of 250 mg three times daily. 

Side effects of Primidone

The most common side effects are dose related and include drowsiness, ataxia, diplopia, and headache.  The initial dose may be associated with an acute toxic reaction with nausea, malaise, sedation, ataxia and confusion.  Long term therapy may be associated with megaloblastic anemias and birth defects.

• Dailymed label info on Primidone
• FDA Primidone

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  Chemical structure of Primidone
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  Ball-and-stick model of Primidone
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  Dupuytren's contracture
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  X-ray of rickets