Buy Primidone (barbiturate) Cas 125-33-7

Primidone, sold under various brand names (including Mysoline), is a barbiturate medication that is used to treat partial and generalized seizures^[7] and essential tremors.^[8] It is taken by mouth.^[7]

Its common side effects include sleepiness, poor coordination, nausea, and loss of appetite.^[7] Severe side effects may include suicide and psychosis.^[8][7] Use during pregnancy may result in harm to the fetus.^[9] Primidone is an anticonvulsant of the barbiturate class;^[7] however, its long-term effect in raising the seizure threshold is likely due to its active metabolite, phenobarbital.^[10] The drug’s other active metabolite is Phenylethylmalonamide (PEMA).

Primidone was approved for medical use in the United States in 1954.^[7] It is available as a generic medication.^[8] In 2023, it was the 239th most commonly prescribed medication in the United States, with more than 1 million prescriptions.^[11][12]

It is licensed for generalized tonic-clonic and complex partial seizures in the United Kingdom.^[13] In the United States, primidone is approved for adjunctive (in combination with other drugs) and monotherapy (by itself) use in generalized tonic-clonic seizures, simple partial seizures, complex partial seizures, and myoclonic seizures.^[13] In juvenile myoclonic epilepsy, it is a second-line therapy, reserved for when the valproates or lamotrigine do not work and when the other second-line therapy, acetazolamide, does not work.^[14] The usual dose for seizure disorder is titrated from 100–125 mg/day up to a maintenance dose of 750-1,500 mg/day (maximum daily dosage is 2 g).^[15]

Open-label case series have suggested that primidone is effective in the treatment of epilepsy.^{[16][17][18][19][20]} Primidone has been compared to phenytoin,^[21] phenobarbital,^[21] mephobarbital, ethotoin, metharbital, and mephenytoin.^[21] In adult comparison trials, primidone has been found to be just as effective.^[21]

Primidone is not indicated for essential tremor but is often used as a first-line therapy for essential tremor, as is propranolol. In tremor amplitude reduction, it is just as effective as propranolol, reducing it by 50%. Both drugs are well studied for this condition, unlike other therapies, and are recommended for initial treatment. A low-dose therapy (50 mg/day) is just as good as a high-dose therapy (750 mg/day). The usual dose range is 120 to 250 mg/day in two divided doses or as one single dose.^[22][15]

Primidone is not the only anticonvulsant used for essential tremor; the others include topiramate and gabapentin. Other pharmacological agents include alprazolam, clonazepam, atenolol, sotalol, nadolol, clozapine, nimodipine, and botulinum toxin A. Many of these drugs were less effective than primidone. Only propranolol has been compared to primidone in a clinical trial.^[22]