Sodium benzoate and Sodium phenylacetate

Sodium Phenylacetate and Sodium Benzoate Injection is indicated as adjunctive therapy in pediatric and adult patients for the treatment of acute hyperammonemia and associated encephalopathy in patients with deficiencies in enzymes of the urea cycle. During acute hyperammonemic episodes, arginine supplementation, caloric supplementation, dietary protein restriction, hemodialysis, and other ammonia lowering therapies should be considered. Sodium Phenylacetate and Sodium Benzoate Injection is a nitrogen binding agent indicated as adjunctive therapy for the treatment of acute hyperammonemia and associated encephalopathy in pediatric and adult patients with deficiencies in enzymes of the urea cycle.

Urea cycle disorders can result from decreased activity of any of the following enzymes: N -acetylglutamate synthetase (NAGS), carbamyl phosphate synthetase (CPS), argininosuccinate synthetase (ASS), ornithine transcarbamylase (OTC), argininosuccinate lyase (ASL), or arginase (ARG). Sodium phenylacetate and sodium benzoate are metabolically active compounds that can serve as alternatives to urea for the excretion of waste nitrogen. Figure 2 is a schematic illustrating how the components of Sodium Phenylacetate and Sodium Benzoate Injection, phenylacetate and benzoate, provide an alternative pathway for nitrogen disposal in patients without a fully functioning urea cycle. Phenylacetate conjugates with glutamine in the liver and kidneys to form phenylacetylglutamine, via acetylation. Phenylacetylglutamine is excreted by the kidneys via glomerular filtration and tubular secretion.

Sodium Phenylacetate and Sodium Benzoate Injection must be diluted with sterile 10% Dextrose Injection (D10W) before administration. Administration must be through a central venous catheter. Administration through a peripheral line may cause burns. Sodium Phenylacetate and Sodium Benzoate Injection is administered intravenously as a loading dose infusion administered over 90 to 120 minutes, followed by an equivalent maintenance dose infusion administered over 24 hours. See Full Prescribing Information for complete dosing recommendations.

None None.

Decreased Potassium Levels: Plasma potassium levels should be carefully monitored and appropriate treatment given when necessary. Conditions Associated with Fluid Overload: Sodium Phenylacetate and Sodium Benzoate Injection contains 30.5 mg of sodium per mL of undiluted product. Caution should be used if Sodium Phenylacetate and Sodium Benzoate Injection is administered to patients with congestive heart failure, severe renal insufficiency, or with conditions in which there is sodium retention with edema. Extravasation: Extravasation of Sodium Phenylacetate and Sodium Benzoate Injection into the perivenous tissues during high flow bolus infusion may lead to skin necrosis, especially in infants. The infusion site must be monitored closely for possible tissue infiltration during drug administration.

The most frequently reported adverse reactions (incidence ≥6%) are vomiting, hyperglycemia, hypokalemia, convulsions, and mental impairment ​

Formal drug interaction studies have not been performed with Sodium Phenylacetate and Sodium Benzoate Injection. Some antibiotics such as penicillin may compete with phenylacetylglutamine and hippurate for active secretion by renal tubules, which may affect the overall disposition of the infused drug. Probenecid is known to inhibit the renal transport of many organic compounds, including aminohippuric acid, and may affect renal excretion of phenylacetylglutamine and hippurate. There have been reports that valproic acid can induce hyperammonemia through inhibition of the synthesis of N-acetylglutamate, a co-factor for carbamyl phosphate synthetase. Therefore, administration of valproic acid to patients with urea cycle disorders may exacerbate their condition and antagonize the efficacy of Sodium Phenylacetate and Sodium Benzoate Injection.

Store at 20°C to 25°C (77°F), excursions permitted to 15°C to 30°C (59°F to 86°F).