What is phenylbutyrate?

PHEBURANE (sodium phenylbutyrate) oral pellets is a nitrogen binding agent. Sodium phenylbutyrate is a white or yellowish-white powder, freely soluble in water and in methanol, and practically insoluble in methylene chloride. It is known chemically as sodium 4-phenylbutanoate with a molecular weight of 186.19 and the molecular formula C 10 H 11 NaO 2 . Structural formula: Each bottle of PHEBURANE contains 84 g of sodium phenylbutyrate (equivalent to 74 g of phenylbutyrate) in 174 g of oral pellets. Each gram of pellets contains 483 mg of sodium phenylbutyrate (equivalent to 423 mg of phenylbutyrate). PHEBURANE contains the following inactive ingredients: ethylcellulose, hypromellose, polyethylene glycol 1500, povidone K25, and sugar spheres. Structural formula

What kind of drug is phenylbutyrate?

The FDA classifies phenylbutyrate as a nitrogen binding agent. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

Can you take phenylbutyrate with other medicines?

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run phenylbutyrate against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

What brand names is phenylbutyrate sold under?

We track 3 phenylbutyrate-containing products in the U.S.: Buphenyl, Olpruva and Pheburane. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

What forms does phenylbutyrate come in?

Across the brands we track, phenylbutyrate is currently marketed as tablet, powder, kit and oral pellets, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Is there a generic phenylbutyrate?

We do not currently list a generic-labelled phenylbutyrate product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.

Phenylbutyrate: uses, dosing, side effects & brands

Phenylbutyrate is a nitrogen binding agent sold in the U.S. under 3 brand and generic names, for sickle cell anemia, cystic fibrosis and myeloproliferative disorders. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.

By the pharmaranks editorial teamReviewed against the FDA (openFDA label, NDC Directory & Enforcement) sourcesHow we research

Key facts

Drug class: Nitrogen Binding Agent
Treats: Sickle Cell Anemia, Cystic Fibrosis and Myeloproliferative Disorders
Available as: Tablet · Powder · Kit · Oral pellets
Sold as: 3 products — Buphenyl, Olpruva and Pheburane
Prescription?: Prescription only
Generic available?: Not in our catalog

How phenylbutyrate is dosed

From the FDA label for Pheburane (application NDA216513). Other phenylbutyrate products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.

PHEBURANE treatment should be supervised by a healthcare provider experienced in the treatment of UCDs. For administration, see full prescribing information. ( 2.1 , 2.4 ) The recommended dosage measured as sodium phenylbutyrate is: Patients weighing < 20 kg: 450–600 mg/kg/day of sodium phenylbutyrate orally. ( 2.1 ) Patients weighing ≥ 20 kg: 9.9–13.0 g/m 2 /day of sodium phenylbutyrate orally. ( 2.1 ) Monitor plasma ammonia levels to determine the need for dosage adjustment. ( 2.2 ) Monitor patients for potential neurotoxicity. ( 2.2 ) For patients with hepatic impairment, start at the lower end of the recommended dosing range. ( 2.3 ) 2.1 Recommended Dosage PHEBURANE treatment should be supervised by a healthcare provider experienced in the treatment of urea cycle disorders. The recommended dosage of PHEBURANE (measured as sodium phenylbutyrate) for patients with urea cycle disorders is: Patients weighing less than 20kg: 450 – 600 mg/kg/day of sodium phenylbutyrate orally. Divide the calculated total daily dose into three to six doses. Administer as three to six divided doses and take with food. Patients weighing greater than or equal to 20 kg: 9.9 – 13 g/m 2 /day of sodium phenylbutyrate orally. Divide the calculated total daily dose into three to six doses. Administer as three to six divided doses and take with food. The maximum dosage is 20…

Phenylbutyrate side effects

The following adverse reactions associated with the use of sodium phenylbutyrate were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily and from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Most common adverse reactions (incidence ≥ 3%) are amenorrhea or menstrual dysfunction (irregular menstrual cycles), decreased appetite, body odor and bad taste or taste aversion. Less Common Clinical Adverse Reactions Blood and lymphatic system disorders: aplastic anemia, ecchymoses Cardiac disorders : arrhythmia Gastrointestinal disorders : abdominal pain, decreased appetite, gastritis, nausea and vomiting, constipation, rectal bleeding, peptic ulcer disease, pancreatitis Metabolism and nutrition disorders: increased weight, edema Nervous system disorders : syncope, headache Psychiatric disorders : depression Renal and urinary disorders : renal tubular acidosis Skin and subcutaneous tissue disorders : rash Laboratory Adverse Reactions Blood and lymphatic system disorders : anemia, leukopenia and leukocytosis, thrombocytopenia, thrombocytosis Hepatobiliary disorders: hyperbilirubinemia, increased blood alkaline phosphatase, increased transaminases Metabolism and nutrition disorders: acidosis, alkalosis, hyperchloraemia,…

Every phenylbutyrate product we track (3)

Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.

Phenylbutyrate products
#	Drug	Rating	Type	Form	Generic?	Typical price
1	Buphenyl	Not yet rated	Prescription	Tablet	—	—	View →
2	Olpruva	Not yet rated	Prescription	Kit	—	—	View →
3

What phenylbutyrate pills look like

Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.

Phenylbutyrate pill imprints
Imprint	Strength	Colour	Shape	Maker
EP340	500 mg	white	oval	—
NAV131	500 mg	white	oval	—
G853	500 mg	white	oval	—

Combination products containing phenylbutyrate

A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.

Relyvrio

Frequently asked questions

What is phenylbutyrate?: PHEBURANE (sodium phenylbutyrate) oral pellets is a nitrogen binding agent. Sodium phenylbutyrate is a white or yellowish-white powder, freely soluble in water and in methanol, and practically insoluble in methylene chloride. It is known chemically as sodium 4-phenylbutanoate with a molecular weight of 186.19 and the molecular formula C 10 H 11 NaO 2 . Structural formula: Each bottle of PHEBURANE contains 84 g of sodium phenylbutyrate (equivalent to 74 g of phenylbutyrate) in 174 g of oral pellets. Each gram of pellets contains 483 mg of sodium phenylbutyrate (equivalent to 423 mg of phenylbutyrate). PHEBURANE contains the following inactive ingredients: ethylcellulose, hypromellose, polyethylene glycol 1500, povidone K25, and sugar spheres. Structural formula
What kind of drug is phenylbutyrate?: The FDA classifies phenylbutyrate as a nitrogen binding agent. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take phenylbutyrate with other medicines?: It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run phenylbutyrate against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is phenylbutyrate sold under?: We track 3 phenylbutyrate-containing products in the U.S.: Buphenyl, Olpruva and Pheburane. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does phenylbutyrate come in?: Across the brands we track, phenylbutyrate is currently marketed as tablet, powder, kit and oral pellets, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.