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Apo-Primidone: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Apo-Primidone - General Information

An antiepileptic agent related to the barbiturates; it is partly metabolized to phenobarbital in the body and owes some of its actions to this metabolite. Adverse effects are reported to be more frequent than with phenobarbital. (From Martindale, The Extra Pharmacopoeia, 30th ed, p309)

 

Pharmacology of Apo-Primidone

Apo-Primidone is a barbiturate with anticonvulsant properties. Apo-Primidone, either alone or used concomitantly with other anticonvulsants, is indicated in the control of grand mal, psychomotor, and focal epileptic seizures. It may control grand mal seizures refractory to other anticonvulsant therapy. Apo-Primidone raises electro- or chemoshock seizure thresholds or alters seizure patterns in experimental animals. Apo-Primidone per se has anticonvulsant activity as do its two metabolites, phenobarbital and phenylethylmalonamide (PEMA). In addition to its anticonvulsant activity, Apo-Primidone potentiates that of phenobarbital in experimental animals.

 

Apo-Primidone for patients

Patient Information:
While taking Primidone, patient should avoid alcohol and other CNS depressant.
Primidone may cause drowsiness and dizziness.
Primidone should not stopped suddently, it may results in status epilepticus.

 

Apo-Primidone Interactions

No information provided.

 

Apo-Primidone Contraindications

Primidone is contraindicated in:

1) patients with porphyria

2) patients who are hypersensitive to phenobarbital.

 

Additional information about Apo-Primidone

Apo-Primidone Indication: For the treatment of epilepsy Mechanism Of Action: Apo-Primidone is a GABA receptor agonist. The mechanism of Apo-Primidone's antiepileptic action is not known. Drug Interactions: Aminophylline The barbiturate decreases the effect of theophylline Dyphylline The barbiturate decreases the effect of theophylline Oxtriphylline The barbiturate decreases the effect of theophylline Theophylline The barbiturate decreases the effect of theophylline Warfarin The barbiturate decreases the anticoagulant effect Acenocoumarol The barbiturate decreases the anticoagulant effect Dicumarol The barbiturate decreases the anticoagulant effect Anisindione The barbiturate decreases the anticoagulant effect Betamethasone The barbiturate decreases the effect of the corticosteroid Cortisone acetate The barbiturate decreases the effect of the corticosteroid Dexamethasone The barbiturate decreases the effect of the corticosteroid Divalproex sodium Valproic acid increases the effect of the barbiturate Felodipine The barbiturate decreases the effect of felodipine Fludrocortisone The barbiturate decreases the effect of the corticosteroid Folic Acid Folic acid decreases the effect of anticonvulsant Felbamate Felbamate increases the effect and toxicity of primidone Gefitinib This CYP3A4 inducer may reduce gefitinib plasma concentrations and pharmacological effects Griseofulvin The barbiturate decreases the effect of griseofulvine Hydrocortisone The barbiturate decreases the effect of the corticosteroid Levonorgestrel Phenobarbital decreases the effect of levonorgestrel Methadone The barbiturate decreases the effect of methadone Methoxyflurane The barbiturate increases the renal toxicity of methoxyflurane Methylprednisolone The barbiturate decreases the effect of the corticosteroid Metronidazole The barbiturate decreases the effect of metronidazole Paramethasone The barbiturate decreases the effect of the corticosteroid Prednisolone The barbiturate decreases the effect of the corticosteroid Prednisone The barbiturate decreases the effect of the corticosteroid Triamcinolone The barbiturate decreases the effect of the corticosteroid Voriconazole The barbiturate decreases the effect of voriconazole Cyclosporine The barbiturate increases the effect of cyclosporine Doxycycline The anticonvulsant decreases the effect of doxycycline Metoprolol The barbiturate decreases the effect of metabolized beta-blocker Propranolol The barbiturate decreases the effect of metabolized beta-blocker Quinidine The anticonvulsant decreases the effect of quinidine Nifedipine The barbiturate decreases the effect of the calcium channel blocker Verapamil The barbiturate decreases the effect of the calcium channel blocker Ethinyl Estradiol This product may cause a slight decrease of contraceptive effect Mestranol This product may cause a slight decrease of contraceptive effect Norethindrone This product may cause a slight decrease of contraceptive effect Chlorotrianisene The enzyme inducer decreases the effect of hormones Clomifene The enzyme inducer decreases the effect of hormones Diethylstilbestrol The enzyme inducer decreases the effect of hormones Estradiol The enzyme inducer decreases the effect of hormones Conjugated Estrogens The enzyme inducer decreases the effect of hormones Estriol The enzyme inducer decreases the effect of hormones Estrone The enzyme inducer decreases the effect of hormones Estropipate The enzyme inducer decreases the effect of hormones Medroxyprogesterone The enzyme inducer decreases the effect of hormones Megestrol The enzyme inducer decreases the effect of hormones Quinestrol The enzyme inducer decreases the effect of hormones Food Interactions: Not Available Generic Name: Primidone Synonyms: Not Available Drug Category: Anticonvulsants; Barbiturates Drug Type: Small Molecule; Approved Other Brand Names containing Primidone: Apo-Primidone; Cyral; Desoxyphenobarbitone; Hexadiona; Hexamidine; Lepimidin; Lepsiral; Liskantin; Majsolin; Medi-Pets; Midone; Milepsin; Misodine; Misolyne; Mizodin; Mizolin; Myidone; Mylepsin; Mylepsinum; Mysedon; Mysoline; Neurosyn; Pms Primidone; Prilepsin; Primacione; Primaclone; Primacone; Primakton; Primidon; Primidone Methanol Solution; Primoline; Prysoline; Pyrimidone "Medi-Pets"; Pyrimidone Medi-Pets; Resimatil; Sertan; Absorption: 90 to 100% Toxicity (Overdose): Not Available Protein Binding: 70% Biotransformation: Hepatic Half Life: 3-23 hours Dosage Forms of Apo-Primidone: Tablet Oral Chemical IUPAC Name: 5-ethyl-5-phenyl-1,3-diazinane-4,6-dione Chemical Formula: C12H14N2O2 Primidone on Wikipedia: https://en.wikipedia.org/wiki/Primidone Organisms Affected: Humans and other mammals