Usual Adult Dose for Hyperammonemia

More than 20 kg:

• Loading Dose: 55 mL/m2 via IV infusion over 90 to 120 minutes
• Maintenance Dose: 55 mL/m2 via IV infusion over 24 hours

Comments:

• Dilute this drug with sterile 10% dextrose injection at 25 mL/kg or greater before administration.
• Coadminister with arginine HCl injection 10%; consult the manufacturer product information for arginine dosing recommendations.

Use: Adjunctive treatment of acute hyperammonemia and associated encephalopathy in patients with deficiencies in urea cycle enzymes (carbamyl phosphate synthetase [CPS], ornithine transcarbamylase [OTC], argininosuccinate synthetase [ASS], and argininosuccinate lyase [ASL])

Usual Pediatric Dose for Hyperammonemia

20 kg or Less:

• Loading Dose: 2.5 mL/kg via IV infusion over 90 to 120 minutes
• Maintenance Dose: 2.5 mL/kg via IV infusion over 24 hours

More than 20 kg:

• Loading Dose: 55 mL/m2 via IV infusion over 90 to 120 minutes
• Maintenance Dose: 55 mL/m2 via IV infusion over 24 hours

Comments:

• Determine dosage by weight (mL/kg) for neonates, infants, and young children and by body surface area (mL/m2) for older children and adolescents.
• Dilute this drug with sterile 10% dextrose injection at 25 mL/kg or greater before administration.
• Coadminister with arginine HCl injection 10%; consult the manufacturer product information for arginine dosing recommendations.

Use: Adjunctive treatment of acute hyperammonemia and associated encephalopathy in patients with deficiencies in urea cycle enzymes (carbamyl phosphate synthetase [CPS], ornithine transcarbamylase [OTC], argininosuccinate synthetase [ASS], and argininosuccinate lyase [ASL])

Renal Dose Adjustments

Caution and close monitoring are recommended.

Liver Dose Adjustments

Caution is recommended.

Precautions

Consult WARNINGS section for additional precautions.

Dialysis

• This drug is dialyzable; however, no dose adjustment guidelines have been reported.
• Hemodialysis should be considered in patients with severe hyperammonemia or in those not responsive to this drug.

Other Comments

Administration Advice:

• Terminate administration of analogous oral drugs, such as sodium phenylbutyrate, prior to infusion of this drug.
• Initiate treatment as soon as the diagnosis of hyperammonemia is made.
• Administer this drug via a central venous catheter only; a peripheral line may cause burns.
• Repeat loading doses should not be administered due to risk of neurotoxicity associated with prolonged plasma levels of sodium phenylacetate.
• Continue maintenance infusions until elevated plasma ammonia levels have been normalized or patient can tolerate oral nutrition and medications.
• Do not administer undiluted product.
• Consider using an antiemetic during infusion to aid control of infusion-associated nausea and vomiting.

Storage Requirements:

• This drug is physically and chemically stable for up to 24 hours at room temperature and room lighting conditions.
• Store this drug at 25 degrees Celsius (77 Fahrenheit).

Reconstitution/Preparation Techniques:

• This drug may be prepared in glass and PVC containers.

IV Compatibility:

• Arginine HCl injection 10% may be mixed in the same container as this drug; no other infusions or drug products should be administered together with this drug.

General:

• Oral therapy, dietary management, and maintenance protein restrictions should be started or reinitiated once elevated ammonia levels have been reduced to the normal range.
• Severe cases of overdose should be managed by hemodialysis (procedure of choice) or peritoneal dialysis if hemodialysis is unavailable.
• Data indicate sodium benzoate is not mutagenic or carcinogenic.

Monitoring:

• Plasma ammonia, glutamine, quantitative plasma amino acids, blood glucose, potassium and other electrolytes, venous or arterial blood gases, AST, ALT, blood chemistry profiles, blood pH, neurological status, Glasgow Coma Scale, tachypnea, CT or MRI scan or funduscopic evidence of cerebral edema and/or damage to gray and white matter, infusion sites (ongoing; during and after drug infusion)
• Chloride and bicarbonate levels (if patient taking high-dose arginine HCl along with this drug)

Patient Advice:

• When your plasma ammonia levels have normalized, you can usually increase your dietary protein intake with the goal of unrestricted protein intake.