primidone /prī″mədōn/ , an anticonvulsant. ▪ INDICATIONS: It is prescribed in the treatment of seizure disorders, including tonic-clonic, psychomotor, and focal epilepsy-like seizures, and has an unlabeled use for treating familial (essential) tremor. ▪ CONTRAINDICATIONS: Porphyria, pregnancy, or known hypersensitivity to this drug or to phenobarbital, a metabolite of primidone, prohibits its use. The drug must be used with caution in those having renal, hepatic, or pulmonary insufficiency. ▪ ADVERSE EFFECTS: The most serious adverse effect, seen on rare occasions, is megaloblastic anemia. Drowsiness, ataxia, and dizziness are common. Drug dependency and other adverse effects of phenobarbital may occur.
