Question

How does treatment with phenylbuterate (or phenylacetate) partially overcome the clinical consequences of urea cycle deficiencies?es treatment with phenylbuterate (or phenylacetate) partially overcome the clinical consequences of urea cycle deficiencies?

Answer 1

Serve as alternatives to urea for the excretion of waste nitrogen. Sodium phenylbutyrate and sodium benzoate can serve as alternatives to urea for the excretion of waste nitrogen. phenylbutyrate, which is the prodrug of phenylacetate, conjugates with glutamine to form phenylacetylglutamine, which is excreted by the kidneys. Similarly, sodium benzoate reduces ammonia content in the blood by conjugating with glycine to form hippuric acid, which is rapidly excreted by the kidneys.

A preparation containing sodium phenylacetate and sodium benzoate is available under the trade name Ammonul. Acidification of the intestinal lumen using lactulose can decrease ammonia levels by protonating ammonia and trapping it in the stool. This is a treatment for hepatic encephalopathy.