Unknown Manufacturer • Phenylbutyric acid is used for the treatment of various conditions, including urea cycle disorders, neonatal-onset deficiency, late-onset deficiency disease in patients with a history of hyperammonemic encephalopathy. Phenylbutyric acid must be combined with dietary protein restriction and, in some cases, essential amino acid supplementation. Phenylbutyric acid, as sodium phenylbutyrate, is used in combination with tauroursodeoxycholic acid to treat amyotrophic lateral sclerosis (ALS) in adults.
Phenylbutyric acid is an agent indicated for the adjunctive therapy for the management of chronic urea cycle disorders due to deficiencies in specific enzymes, including the neonatal-onset deficiency and late-onset disease with a history of hyperammonemic encephalopathy.
Sodium phenylbutyrate is the most commonly used salt used in drug products of phenylbutyric acid. Sodium phenylbutyrate is a pro-drug that rapidly metabolizes to phenylacetate. Phenylacetate is conjugated with phenylacetyl-CoA, which in turn combines with glutamine via acetylation to form phenylacetylglutamine. Phenylacetylglutamine is then excreted by the kidneys, thus providing an alternate mechanism of waste nitrogen excretion to the urea cycle. Phenylacetylglutamine is comparable to urea, as each molecule contains two moles of nitrogen.
