Adult Dosing

Urea cycle disorders

• Patients < 20 kg: 450-600 mg/kg/day divided q4-6hrs PO
• Patients > 20 kg: 9.9–13.0 g/m²/day

Note:

• To be taken in equally divided amounts with each meal or feeding
• The powder is to be mixed with food (solid or liquid), for immediate use

Pediatric Dosing

Urea cycle disorders

• Patients < 20 kg: 450-600 mg/kg/day divided q4-6hrs PO
• Patients > 20 kg: 9.9–13.0 g/m²/day

• Urea cycle disorders
• Adjunctive therapy in the chronic management of patients with urea cycle disorders involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS). It is indicated in all patients with neonatal-onset deficiency (complete enzymatic deficiency, presenting within the first 28 days of life). It is also indicated in patients with late-onset disease (partial enzymatic deficiency, presenting after the first month of life) who have a history of hyperammonemic encephalopathy.

• Hypersensitivity to any of the ingredients of the product
• Management of acute hyperammonemia which is a medical emergency

• N/A

Renal Dose Adjustment (Based on CrCl)

• Renal impairment: Dose adjustments not defined; caution advised

Hepatic Dose Adjustment

• Hepatic impairment: Dose adjustments not defined; caution advised

• Sodium phenylbutyrate preparation contains sodium, caution should be advised in patients with congestive heart failure or severe renal insufficiency, and in clinical states in which there is sodium retention with edema
• Use cautiously when administering the drug to patients with hepatic or renal insufficiency or inborn errors of beta oxidation
• Concurrent use of corticosteroids may cause the breakdown of body protein and increase plasma ammonia levels
• There have been published reports of hyperammonemia being induced by haloperidol and by valproic acid
• Plasma levels of ammonia, arginine, branched-chain amino acids, and serum proteins should be maintained within normal limits, and plasma glutamine should be maintained at levels less than 1,000 µmol/L
• Periodically monitor serum drug levels of phenylbutyrate and its metabolites, phenylacetate and phenylacetylglutamine

Pregnancy Category:C

Breastfeeding: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when administered to a nursing woman.

• CNS: Headache, syncope
• PSYCHIATRY: Depression
• GI: Abdominal pain, gastritis, nausea, vomiting, constipation, rectal bleeding, peptic ulcer disease, pancreatitis
• HEMA: Aplastic anemia, ecchymoses
• DERM: Rash
• CV: Arrhythmia
• GU: Renal tubular acidosis
• METABOLISM: Weight gain
• MISCELLANEOUS: Edema

• Pro-drug; rapidly metabolized to phenylacetate which conjugates with glutamine to form phenylacetylglutamine, a nitrogen waste product that is excreted renally
• Metabolism: Majorly metabolised by liver and kidney
• Excretion: 80-100% of drug is excreted in urine as phenylacetylglutamine
• Half-life: 0.76 hrs

US Trade Name(s)

• Buphenyl

US Availability

sodium phenylbutyrate (generic)

• TABS: 500 mg
• PWDR: 3 gm/teaspoonful

Buphenyl

• TABS: 500 mg
• PWDR: 3 gm/teaspoonful

Canadian Trade Name(s)

• N/A

Canadian Availability

• N/A

UK Trade Name(s)

• Ammonaps

UK Availability

Ammonaps

• TABS: 500 mg
• PWDR: 940 mg/gm granules

Australian Trade Name(s)

• N/A

Australian Availability

• N/A

Endocrine/Metabolic

Urea Cycle Disorder Agent

Miscellaneous Agents

Drug Name: Buphenyl 500 MG Oral Tablet

Ingredient(s): Phenylbutyrate

Imprint: UCY;500

Color(s): White

Shape: Oval

Size (mm): 16.00

Score: 1

Inactive Ingredient(s): cellulose, microcrystalline / magnesium stearate / silicon dioxide

Drug Label Author:
Ucyclyd Pharma Inc.

DEA Schedule:
Non-Scheduled