Interactions between valproic-acid(valproic acid) and Sodium phenylacetate (sodium phenylacetate)
valproic acid and sodium phenylacetate (Major Drug-Drug)
CONTRAINDICATED: Coadministration with valproic acid may diminish the therapeutic effects of sodium benzoate and sodium phenylacetate in the treatment of acute hyperammonemia due to deficiencies in enzymes of the urea cycle. There have been reports that valproic acid can induce hyperammonemia through inhibition of the synthesis of N-acetylglutamate, a co-factor for the urea cycle enzyme carbamyl phosphate sythetase. Hyperammonemic encephalopathy, sometimes fatal, has been reported following initiation of valproate therapy in patients with urea cycle disorders, particularly ornithine transcarbamylase deficiency.
MANAGEMENT: The use of valproic acid is contraindicated in patients with known urea cycle disorders.
