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Sodium Phenylbutyrate Dosage

Applies to the following strength(s): 100% ; 500 mg

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Urea Cycle Disorders

Powder and Tablet:
Less than 20 kg: 450 to 600 mg/kg/day
20 kg or Greater: 9.9 to 13 g/m2/day

Comments: Administer orally in equally divided doses with each meal or feeding (i.e., 3 to 6 times a day).

Uses:
-Adjunctive therapy in the chronic management of urea cycle disorders involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).
-Treatment of neonatal-onset deficiency (complete enzymatic deficiency, presenting within the first 28 days of life) and late-onset disease (partial enzymatic deficiency, presenting after the first month of life) with history of hyperammonemic encephalopathy.

Usual Pediatric Dose for Urea Cycle Disorders

Powder:
Less than 20 kg: 450 to 600 mg/kg/day
20 kg or Greater: 9.9 to 13 g/m2/day

Tablet:
20 kg or Less: Not recommended.
Greater than 20 kg: 9.9 to 13 g/m2/day

Comments: Administer orally in equally divided doses with each meal or feeding (i.e., 3 to 6 times a day).

Uses:
-Adjunctive therapy in the chronic management of urea cycle disorders involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).
-Treatment of neonatal-onset deficiency (complete enzymatic deficiency, presenting within the first 28 days of life) and late-onset disease (partial enzymatic deficiency, presenting after the first month of life) with history of hyperammonemic encephalopathy.

Renal Dose Adjustments

Renal Insufficiency: Use with caution.

Liver Dose Adjustments

Hepatic Insufficiency: Use with caution.

Dialysis

Data not available.

Other Comments

Administration Advice:
-Initiate treatment immediately to improve survival and clinical outcomes.
-Administer the powder formulation orally via mouth or tube (gastrostomy or nasogastric).
-For the powder formulation, lightly shake the bottle before use.
-Consult the manufacturer product information for nutritional management recommendations.

Storage Requirements:
-When dissolved in water, the powder formulation is stable for up to one week at room temperature or under refrigeration.

Reconstitution/Preparation Techniques:
-Mix the powder formulation with food (solid or liquid, e.g., mashed potatoes, apple sauce, water, apple juice, protein-free infant formula) for immediate use.
-When the powder formulation is added to a liquid, only the active substance will dissolve; the excipients will not dissolve.

General:
-For each gram of sodium phenylbutyrate administered, between 0.12 to 0.15 grams of phenylacetylglutamine nitrogen are produced.
-The safety and efficacy of doses in excess of 20 g/day have not been established.
-This drug may be required life-long unless orthotopic liver transplantation is elected.
-In the event of an overdose, hemodialysis or peritoneal dialysis may be beneficial.

Monitoring:
-Urinalysis, hematological tests, blood chemistry profile, serum potassium, serum proteins, and plasma levels of glutamine, ammonia, arginine, branched-chain amino acids (routinely)
-Serum levels of phenylbutyrate, phenylacetate, phenylacetylglutamine (periodically)

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