Primidone is an anticonvulsant of the pyrimidinedione class, the active metabolites of which, phenobarbital (major) and phenylethylmalonamide (PEMA) (minor), are also anticonvulsants. It is used mainly to treat complex partial, simple partial, generalized tonic-clonic seizures, myoclonic, and akinetic seizures and since the 1980s it has been a valuable alternative to propranolol in the treatment of essential tremor. Unlike other anticonvulsants such as carbamazepine and valproic acid, primidone is rarely used in the treatment of bipolar disorder or any other psychiatric problem...