Description: Valproate is a generic term used to describe valproic acid, its salts and derivatives. It is available in various forms including the sodium salts (valproate semisodium and sodium valproate), the amide derivative (valpromide), or as valproic acid. Valproate is a carboxylic acid anticonvulsant. It has been suggested that its antiepileptic activity is related to increased brain levels of γ-aminobutyric acid (GABA).
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Description: Valproate is a generic term used to describe valproic acid, its salts and derivatives. It is available in various forms including the sodium salts (valproate semisodium and sodium valproate), the amide derivative (valpromide), or as valproic acid. Valproate is a carboxylic acid anticonvulsant. It has been suggested that its antiepileptic activity is related to increased brain levels of γ-aminobutyric acid (GABA).
Pharmacokinetics:
Absorption: Valproic acid is rapidly and completely absorbed from the GI tract while valpromide is absorbed slower than valproic acid. Time to peak plasma concentration: Oral: Approx 4 hr; extended release: 4-17 hr. Bioavailability: Extended release: Approx 90%.
Distribution: Plasma protein binding (concentration dependent): 80-90%; free fraction: Increases from approx 10% at 40 mcg/mL to approx 18.5% at 130 mcg/mL; decreases in the elderly and patients w/ hepatic or renal impairment. Crosses the placenta; enters breast milk.
Metabolism: Valpromide is almost completely and rapidly metabolised in the liver to valproic acid. Valproic acid is extensively metabolised by liver, via glucuronidation and mitochondrial β-oxidation. Excretion: Excreted in urine (30-50% as glucuronide conjugate; 2 mth: 7-13 hr.