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Sodium Phenylbutyrate .94 g/g Powder — NDC 42794-086-14 (Billing 42794-0086-14)

by Sigmapharm Laboratories, LLC · 1 BOTTLE in 1 CARTON / 250 g in 1 BOTTLE

This is a package of Sodium Phenylbutyrate .94 g/g Powder from Sigmapharm Laboratories, LLC, no longer marketed (first marketed Apr 2013), no longer in the FDA NDC Directory. It is this product's only package size.

NDC 42794-0086-14
🏷️ FDA NDC (as labeled) 42794-086-14 billing pads the product segment with a zero
Rx only Generic Discontinued Non-controlled ⚠ Discontinued by firm ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 1, 2026 · this listing last changed Jun 25, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

NDC database record

One package, one record: these facts belong to NDC 42794-086-14 alone.

Record
FDA NDC Directory package listing · Human prescription drug
Code segments
42794 labeler · 086 product · 14 package
Package marketed since
Apr 8, 2013
Sample package
No — commercial package
Listing certified through
Dec 31, 2026
Barcode (UPC)
0342794086144
FDA record last changed
Jun 25, 2026
Past resolved recalls for this product (2)
Class II · Sep 21, 2021 · Terminated — Failed Impurities/Degradation Specifications; Out of Specification impurity results obtained during routine testing. (SigmaPharm Laboratories LLC) · FDA recall D-0898-2021
Class II · Aug 13, 2021 · Terminated — Failed Impurities Specifications: Out of Specification impurity results obtained during routine testing. (SigmaPharm Laboratories LLC) · FDA recall D-0766-2021
⚠️
Excluded from the active FDA NDC Directory. The labeler reported this product as discontinued, so it is excluded from the active NDC Directory. The listing was last certified through Feb 2024. A label may still appear on DailyMed, but the NDC is no longer in the current FDA NDC Directory. Search the FDA NDC Directory ↗

Identity & classification

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 42794-086-14
Product NDC 42794-086
11-digit billing NDC 42794008614
NCPDP billing unit GM — per gram (weight)
RxCUI 984105
UNII NT6K61736T
UPC 0342794086144
Application # ANDA202819
SPL Set ID e914d451-6122-43f9-af8d-c80ed1cb215d
Established class (EPC) Nitrogen Binding Agent
Mechanism of action Ammonium Ion Binding Activity
DEA schedule Non-controlled
Marketing category ANDA
Marketing status Discontinued
FDA listing status Discontinued by firm (certified through Feb 2024)
Marketing start 2013-04-08
Route ORAL
Dosage form POWDER
Substance SODIUM PHENYLBUTYRATE

Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification

GPI-14 30908060002950
GPI class Sodium Phenylbutyrate
GCN Seq No 026631
GCN 43370
HICL code 011317
Ingredient (HICL) Sodium Phenylbutyrate
HIC1 code D
Therapeutic class — broad (HIC1) Biliary System/Gastro-Intestinal System
HIC2 code D9
Therapeutic class — intermediate (HIC2) Ammonia Inhibitors
HIC3 code D9A
Therapeutic class — specific (HIC3) Ammonia Inhibitors
AHFS code 40:10.00.00
AHFS class Ammonia Detoxicants
FDB label name SODIUM PHENYLBUTYRATE POWDER
FDB brand name Sodium Phenylbutyrate
Legend status F — Federal legend — prescription drug or device
Quick answers
  • GSN (GCN sequence number): 026631
  • GCN: 43370
  • GPI-14 (Medi-Span): 30908060002950
  • HICL (First Databank): 011317
  • AHFS class code: 40:10.00.00
  • RxCUI (RxNorm): 984105
Why two NDCs? The FDA registers this code as 42794-086-14 — a 5-3-2 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the product segment → 42794-0086-14. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

RxNorm drug class

This medicine belongs to the Nitrogen Binding Agent class.

Pharmacologic class Nitrogen Binding Agent
Drug family (ATC) Various alimentary tract and metabolism products
How it works Ammonium Ion Binding Activity
Where does this data come from?
Therapeutic classes from RxNorm RxClass (U.S. National Library of Medicine) — Established Pharmacologic Class (FDA), ATC drug family (WHO) and mechanism of action, matched by this product’s RxCUI.

Clinical

Label name SODIUM PHENYLBUTYRATE POWDER Ingredient Sodium Phenylbutyrate
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer gPer package
Retail pharmacies payNADAC · weekly Not in the retail survey — common for institutional, discontinued, or low-volume packs.
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · quarterly No Part D plan price is available for this NDC in our data.
ℹ️
No price is published for this exact package yet. CMS surveys NADAC per package size, so a different pack of the same drug often has one.
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

Packaging — all sizes for this product

Package NDCDescription Marketing startMarketing endStatus
42794-0086-14 You're viewing this Main listing 1 BOTTLE in 1 CARTON / 250 g in 1 BOTTLE 2013-04-08 — Discontinued by firm

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Sodium Phenylbutyrate .94 g/gthis 42794-0086-14 Sigmapharm 1 bottle — — Discontinued —
Sodium Phenylbutyrate .94 g/g 49884-0006-04 Par 1 bottle — — FDA listed —
Buphenyl .94 g/g 75987-0070-09 Horizon 1 bottle — — FDA listed —
About this product: this is a generic version of the medicine. FDA equivalence ratings are shown when available, and other versions are listed above, least expensive first.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

Availability & generic status

🏛️
2013
On the market since
Apr 2013
📍
2026
Currently FDA-listed
13 years listed
🔓
·
Generic on the market
this product is a generic
✅This is a generic drug

This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.

Where does this data come from?
Patents and exclusivity from the FDA Orange Book (small-molecule drugs), refreshed from public FDA data. Generic launch timing is an estimate, not a guarantee.

Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

We could not link this NDC to a current FDA Structured Product Label. An inactive-ingredient list is therefore not available from this source.
Where does this data come from?
Source: official FDA Structured Product Labeling (SPL) via DailyMed and the openFDA label index. Structured IACT rows and label-wide narrative are kept separate; availability and product-level specificity depend on the submitted label.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

Manufacturer & labeler

LabelerSigmapharm Laboratories, LLC
Application holderSIGMAPHARM LABORATORIES LLC
FDA applicationANDA202819 (ANDA)
Labeler code42794
First marketedApr 2013
Product typeHuman Prescription Drug
Portfolio28 products on file

More NDCs from Sigmapharm Laboratories, LLC labeler code 42794

The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Very long sections are excerpted here and marked; the full text is on DailyMed (linked in the sources below). Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration ⛔ Contraindications ⚠️ Warnings 🤒 Adverse Reactions 🆘 Overdosage 🧬 Clinical Pharmacology 📦 How Supplied / Storage and Handling 📋 Description ⚠️ Precautions 🧬 Pharmacokinetics 📄 Patient Package Insert 📄 Package Label / Principal Display Panel
🎯 Indications and Usage ~2 min read ▾

INDICATIONS AND USAGE Sodium Phenylbutyrate Powder is indicated as 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.

It is important that the diagnosis be made early and treatment initiated immediately to improve survival. Any episode of acute hyperammonemia should be treated as a life-threatening emergency. Sodium Phenylbutyrate Powder must be combined with dietary protein restriction and, in some cases, essential amino acid supplementation.

(See Nutritional Supplementation subsection of the DOSAGE AND ADMINISTRATION section.) Previously, neonatal-onset disease was almost universally fatal within the first year of life, even when treated with peritoneal dialysis and essential amino acids or their nitrogen-free analogs. However, with hemodialysis, use of alternative waste nitrogen excretion pathways (sodium phenylbutyrate, sodium benzoate, and sodium phenylacetate), dietary protein restriction, and, in some cases, essential amino acid supplementation, the survival rate in newborns diagnosed after birth but within the first month of life is almost 80%.

Most deaths have occurred during an episode of acute hyperammonemic encephalopathy. Patients with neonatal-onset disease have a high incidence of mental retardation. Those who had IQ tests administered had an incidence of mental retardation as follows: ornithine transcarbamylase deficiency, 100% (14/14 patients tested); argininosuccinic acid synthetase deficiency, 88% (15/17 patients tested); and carbamylphosphate synthetase deficiency, 57% (4/7 patients tested).

Retardation was severe in the majority of the retarded patients. In patients diagnosed during gestation and treated prior to any episode of hyperammonemic encephalopathy, survival is 100%, but even in these patients, most subsequently demonstrate cognitive impairment or other neurologic deficits. In late-onset deficiency patients, including females heterozygous for ornithine transcarbamylase deficiency, who recover from hyperammonemic encephalopathy and are then treated chronically with sodium phenylbutyrate and dietary protein restriction, the survival rate is 98%.

The two deaths in this group of patients occurred during episodes of hyperammonemic encephalopathy. However, compliance with the therapeutic regimen has not been adequately documented to allow evaluation of the potential for Sodium Phenylbutyrate Powder and dietary protein restriction to prevent mental deterioration and recurrence of hyperammonemic encephalopathy if carefully adhered to. The majority of these patients tested (30/46 or 65%) have IQ's in the average to low average/borderline mentally retarded range.

Reversal of pre-existing neurologic impairment is not likely to occur with treatment and neurologic deterioration may continue in some patients. Even on therapy, acute hyperammonemic encephalopathy recurred in the majority of patients for whom the drug is indicated. Sodium Phenylbutyrate Powder may be required life-long unless orthotopic liver transplantation is elected.

(See CLINICAL PHARMACOLOGY , Pharmacodynamics subsection for the biochemical effects of Sodium Phenylbutyrate Powder).

⏱️ Dosage and Administration ~1 min read ▾

DOSAGE AND ADMINISTRATION For oral use only. The use of Sodium Phenylbutyrate Tablets is indicated for children weighing more than 20 kg and for adults. The usual total daily dose of Sodium Phenylbutyrate Powder for patients with urea cycle disorders is 450 – 600 mg/kg/day in patients weighing less than 20 kg, or 9.9 – 13 g/m 2 /day in larger patients.

The powder is to be taken in equally divided amounts with each meal or feeding (i.e., three to six times per day). Sodium Phenylbutyrate Powder Powder is indicated for oral use (via mouth, gastrostomy, or nasogastric tube) only. The powder is to be mixed with food (solid or liquid) for immediate use; however, when dissolved in water, Sodium Phenylbutyrate Powder has been shown to be stable for up to one week at room temperature or refrigerated.

Sodium phenylbutyrate is very soluble in water (5 grams per 10 mL). When Sodium Phenylbutyrate Powder is added to a liquid, only sodium phenylbutyrate will dissolve, the excipients will not. The effect of food on sodium phenylbutyrate has not been determined.

Each level yellow teaspoon (enclosed) dispenses 3.2 grams of powder and 3 grams of sodium phenylbutyrate. Each level blue tablespoon (enclosed) dispenses 9.1 grams of powder and 8.6 grams of sodium phenylbutyrate. Shake lightly before use.

The safety or efficacy of doses in excess of 20 grams per day has not been established.

⛔ Contraindications 17 words ▾

CONTRAINDICATIONS Sodium Phenylbutyrate Powder should not be used to manage acute hyperammonemia, which is a medical emergency.

⚠️ Warnings 147 words ▾

WARNINGS Sodium Phenylbutyrate Powder contains 11.7 grams of sodium per 100 grams of powder, corresponding to 125 mg of sodium per gram of sodium phenylbutyrate (12.4% w/w). Sodium Phenylbutyrate Powder should be used with great care, if at all, in patients with congestive heart failure or severe renal insufficiency, and in clinical states in which there is sodium retention with edema. Because Sodium Phenylbutyrate Powder is metabolized in the liver and kidney, and phenylacetylglutamine is primarily excreted by the kidney, use caution when administering the drug to patients with hepatic or renal insufficiency or inborn errors of beta oxidation.

Probenecid is known to inhibit the renal transport of many organic compounds, including hippuric acid, and may affect renal excretion of the conjugated product of Sodium Phenylbutyrate Powder as well as its metabolite. Use of corticosteroids may cause the breakdown of body protein and increase plasma ammonia levels.

🤒 Adverse Reactions ~2 min read ▾

ADVERSE REACTIONS The assessment of clinical adverse events came from 206 patients treated with sodium phenylbutyrate. Adverse events (both clinical and laboratory) were not collected systematically in these patients, but were obtained from patient-visit reports by the 65 co-investigators. Causality of adverse effects is sometimes difficult to determine in this patient population because they may result from either the underlying disease, the patient's restricted diet, intercurrent illness, or Sodium Phenylbutyrate Powder.

Furthermore, the rates may be under-estimated because they were reported primarily by parent or guardian and not the patient. Clinical Adverse Events In female patients, the most common clinical adverse event reported was amenorrhea/menstrual dysfunction (irregular menstrual cycles), which occurred in 23% of the menstruating patients. Decreased appetite occurred in 4% of all patients.

Body odor (probably caused by the metabolite, phenylacetate) and bad taste or taste aversion were each reported in 3% of patients. Other adverse events reported in 2% or fewer patients were: Gastrointestinal: abdominal pain, gastritis, nausea and vomiting; constipation, rectal bleeding, peptic ulcer disease, and pancreatitis each occurred in one patient. Hematologic: aplastic anemia and ecchymoses each occurred in one patient.

Cardiovascular: arrhythmia and edema each occurred in one patient. Renal: renal tubular acidosis Psychiatric: depression Skin: rash Miscellaneous: headache, syncope, and weight gain Neurotoxicity was reported in cancer patients receiving intravenous phenylacetate, 250–300 mg/kg/day for 14 days, repeated at 4-week intervals. Manifestations were predominately somnolence, fatigue, and lightheadedness; with less frequent headache, dysgeusia, hypoacusis, disorientation, impaired memory, and exacerbation of a pre-existing neuropathy.

These adverse events were mainly mild in severity. The acute onset and reversibility when the phenylacetate infusion was discontinued suggest a drug effect. Laboratory Adverse Events In patients with urea cycle disorders, the frequency of laboratory adverse events by body system were: Metabolic: acidosis (14%), alkalosis and hyperchloremia (each 7%), hypophosphatemia (6%), hyperuricemia and hyperphosphatemia (each 2%), and hypernatremia and hypokalemia (each 1%).

Nutritional: hypoalbuminemia (11%) and decreased total protein (3%). Hepatic: increased alkaline phosphatase (6%), increased liver transaminases (4%), and hyperbilirubinemia (1%). Hematologic: anemia (9%), leukopenia and leukocytosis (each 4%), thrombocytopenia (3%), and thrombocytosis (1%).

The clinician is advised to routinely perform urinalysis, blood chemistry profiles, and hematologic tests. To report SUSPECTED ADVERSE REACTIONS , contact Sigmapharm Laboratories, LLC, Pharmacovigilance at 1-855-332-0731 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

🆘 Overdosage 38 words ▾

OVERDOSAGE No adverse experiences have been reported involving overdoses of sodium phenylbutyrate in patients with urea cycle disorders. In the event of an overdose, discontinue the drug and institute supportive measures. Hemodialysis or peritoneal dialysis may be beneficial.

🧬 Clinical Pharmacology 59 words ▾

CLINICAL PHARMACOLOGY Sodium phenylbutyrate is a pro-drug and is rapidly metabolized to phenylacetate. Phenylacetate is a metabolically-active compound that conjugates with glutamine via acetylation to form phenylacetylglutamine. Phenylacetylglutamine then is excreted by the kidneys.

On a molar basis, it is comparable to urea (each containing two moles of nitrogen). Therefore, phenylacetylglutamine provides an alternate vehicle for waste nitrogen excretion.

📦 How Supplied / Storage and Handling 106 words ▾

HOW SUPPLIED Sodium Phenylbutyrate Powder is available in 500 cc bottles, which hold 266 grams of powder, containing 250 grams of sodium Phenylbutyrate (NDC 42794-086-14). The bottles are equipped with child-resistant caps. Measurers are provided.

Each level yellow teaspoon (enclosed) dispenses 3.2 grams of powder and 3 grams of Sodium Phenylbutyrate. Each level blue tablespoon (enclosed) dispenses 9.1 grams of powder and 8.6 grams of Sodium Phenylbutyrate. STORE AT 20ºC TO 25ºC (68ºF TO 77ºF) [SEE USP CONTROLLED ROOM TEMPERATURE].

AFTER OPENING, KEEP BOTTLE TIGHTLY CLOSED. Manufactured by: Sigmapharm Laboratories, LLC Bensalem, PA 19020 NDC 42794-086-14 bottle containing 250 grams of sodium phenylbutyrate powder. OS086-04 REV.0817

📋 Description 102 words ▾

DESCRIPTION Sodium Phenylbutyrate Powder for oral, nasogastric, or gastrostomy tube administration contain sodium phenylbutyrate. Sodium phenylbutyrate is an off-white crystalline substance which is soluble in water and has a strong salty taste. Sodium phenylbutyrate also is freely soluble in methanol and practically insoluble in acetone and diethyl ether.

It is known chemically as 4-phenylbutyric acid, sodium salt with a molecular weight of 186 and the molecular formula C 10 H 11 O 2 Na. Chemical Structure: Each gram of Sodium Phenylbutyrate Powder contains 0.94 grams of sodium phenylbutyrate and the inactive ingredients calcium stearate NF, and colloidal silicon dioxide NF. chemical structure

⚠️ Precautions ~1 min read ▾

General: Sodium Phenylbutyrate Powder should not be administered to patients with known hypersensitivity to sodium phenylbutyrate or any component of this preparation. There have been published reports of hyperammonemia being induced by haloperidol and by valproic acid. Neurotoxicity of phenylacetate in animals: When given subcutaneously to rat pups, 190–474 mg/kg phenylacetate caused decreased proliferation and increased loss of neurons, and it reduced CNS myelin.

Cerebral synapse maturation was retarded, and the number of functioning nerve terminals in the cerebrum was reduced, which resulted in impaired brain growth. Prenatal exposure of rat pups to phenylacetate produced lesions in layer 5 of the cortical pyramidal cells; dendritic spines were longer and thinner than normal and reduced in number. Information for Patients: The full text of the separate insert of information for patients is reprinted at the end of the labeling.

Laboratory Tests: 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. Serum drug levels of phenylbutyrate and its metabolites, phenylacetate and phenylacetylglutamine, should be monitored periodically. Carcinogenesis, Mutagenesis, Impairment of Fertility: Carcinogenicity, mutagenicity, and fertility studies of sodium phenylbutyrate have not been conducted.

Pregnancy: Pregnancy Category C. Animal reproduction studies have not been conducted with Sodium Phenylbutyrate Powder. It is also not known whether Sodium Phenylbutyrate Powder can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity.

Sodium Phenylbutyrate Powder should be given to a pregnant woman only if clearly needed. Nursing Mothers: 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 Sodium Phenylbutyrate Powder is administered to a nursing woman.

Pediatric Use: The use of tablets for neonates, infants and children to the weight of 20 kg is not recommended. ( See Dosage and Administration ).

🧬 Pharmacokinetics ~2 min read ▾

PHARMACOKINETICS General: Pharmacokinetic studies have not been conducted in the primary patient population (neonates, infants, and children), but pharmacokinetic data were obtained from normal adult subjects. Absorption: Peak plasma levels of phenylbutyrate occur within 1 hour after a single dose of 5 grams of sodium phenylbutyrate powder with a C max of 195 µg/mL under fasting conditions. The effect of food on phenylbutyrate's absorption is unknown.

Disposition: The overall disposition of sodium phenylbutyrate and its metabolites has not been characterized fully. However, the drug is known to be metabolized to phenylacetate and subsequently to phenylacetylglutamine. However, the drug is known to be metabolized to phenylacetate and subsequently to phenylacetylglutamine.

Following oral administration of 5 grams of the powder, measurable plasma levels of phenylbutyrate and phenylacetate were detected 15 and 30 minutes after dosing, respectively, and phenylacetylglutamine was detected shortly thereafter. The pharmacokinetic parameters for phenylbutyrate for C max (µg/mL), T max (hours), and elimination half-life (hours) were 195, 1.00, and 0.76, respectively, and for phenylacetate were 45.3, 3.55, and 1.29, respectively. The major sites for metabolism of sodium phenylbutyrate are the liver and kidney.

Excretion: A majority of the administered compound (approximately 80 – 100%) was excreted by the kidneys within 24 hours as the conjugation product, phenylacetylglutamine. For each gram of sodium phenylbutyrate administered, it is estimated that between 0.12 – 0.15 grams of phenylacetylglutamine nitrogen are produced. Pharmacodynamics: In patients with urea cycle disorders, Sodium Phenylbutyrate Powder decreased elevated plasma ammonia glutamine levels.

It increases waste nitrogen excretion in the form of phenylacetylglutamine. Special Populations Gender: Significant gender differences were found in the pharmacokinetics of phenylbutyrate and phenylacetate, but not for phenylacetylglutamine. The pharmacokinetic parameters (AUC and C max) , for both plasma phenylbutyrate and phenylacetate were about 30 to 50 percent greater in females than in males.

Hepatic insufficiency: In patients who did not have urea cycle disorders but had impaired hepatic function, the metabolism and excretion of sodium phenylbutyrate were not affected. However, this information was obtained from unvalidated, uncontrolled case studies.

📄 Patient Package Insert ~3 min read ▾

PATIENT PACKAGE INSERT Sodium Phenylbutyrate Powder (SO-dee-um fen-ill-BYOU-tih-rate) What is the most important information I should know about Sodium Phenylbutyrate Powder? Sodium Phenylbutyrate Powder is prescribed along with changes in diet for long-term treatment of urea cycle disorders. Sodium Phenylbutyrate Powder can only be obtained with a prescription from your doctor.

Sodium Phenylbutyrate Powder must be taken exactly as the doctor prescribes; do not increase or decrease the dose of this medication without the doctor's approval. What are urea cycle disorders? Urea cycle disorders include a group of diseases, each having a specific liver enzyme deficiency.

Because they are inherited, other family members may be affected. These disorders vary in severity and may be first detected at various ages, from newborn infants to adults. They lead to increased amounts of ammonia in the blood, which may cause disturbed brain function and severe brain damage.

Typical signs of the disease are decreased mental awareness, vomiting, combativeness, slurred speech, unstable gait, and unconsciousness. The diagnosis of urea cycle disorders requires special laboratory tests. These typical signs of the disease may recur after the diagnosis is made if the condition is not under control.

If they do, the doctor should be notified immediately because this is a medical emergency. An infection can cause the condition to go out of control. Therefore, if a fever develops, the doctor should be seen immediately.

A patient or carrier of these disorders should wear a Medic Alert tag stating the diagnosis. In the event that the patient has a sudden, rapid accumulation of ammonia in the blood, and, therefore, in the brain, leading to unconsciousness, the doctor will be alerted to treat the disease properly. Periodically, depending upon the severity of a particular patient's urea cycle disorder, it will be necessary to perform blood tests.

These include plasma ammonia, plasma amino acid levels, and other more routine blood tests to evaluate nutritional status. What is Sodium Phenylbutyrate Powder? Sodium Phenylbutyrate Powder is a drug that helps to prevent ammonia from accumulating in the blood.

Sodium Phenylbutyrate Powder aids the body in eliminating substances that produce ammonia. However, despite drug treatment, blood ammonia levels may become elevated periodically and there may be episodes of altered brain function in association with these ammonia elevations. Patients who have disease onset as newborns have a high incidence of mental retardation.

Medical attention should be obtained as soon as signs appear (see above under "What are urea cycle disorders?"). Sodium Phenylbutyrate Powder may be used as life-long therapy or as a temporary measure until liver transplantation is performed. What diet should I or my child follow?

In addition to taking Sodium Phenylbutyrate Powder, it is equally important that a prescribed diet be followed. Because there is great variability in the severity of urea cycle disorders, each patient's diet should be custom designed by a physician and a nutritionist. Because the diet is so important, it is recommended that the prescribed diet be discussed with a nutritionist who is familiar with urea cycle disorders.

Who should not take Sodium Phenylbutyrate Powder? Sodium Phenylbutyrate Powder is prescribed only for patients with urea cycle disorders. It is not to be used for any other reason.

Keep the medication in a safe place where children cannot reach it. What other medical conditions may also be present that could increase the risk of taking Sodium Phenylbutyrate Powder? Heart failure or decreased kidney function may lead to retention of the sodium content of Sodium Phenylbutyrate Powder with potentially serious consequences such as worsening heart failure, high blood pressure, and swelling.

If these medical conditions are present, the doctor will determine if your child should take Sodium Phenylbutyrate Powder. How sho… [Excerpted — this section continues on DailyMed.]

📄 Package Label / Principal Display Panel 25 words ▾

SODIUM PHENYLBUTYRATE POWDER CONTAINER & CARTON LABEL SIGMAPHARM LABORATORIES, LLC SODIUM PHENYLBUTYRATE POWDER 250 Grams RX ONLY CONTAINER LABEL CARTON LABEL container label carton label

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗

Medicare Part D spend CMS · PART D · 2026 (Q1)

Medicare Part D (outpatient prescription) spending for Sodium Phenylbutyrate — the program that covers self-administered drugs. 2 manufacturers.
⚠️ Drug-level data: CMS publishes Part D spending by drug, not by NDC — these figures combine every manufacturer, strength and package size sold under the name Sodium Phenylbutyrate. That’s a different level of aggregation than the Medicaid card above, which is specific to this exact 11-digit NDC (pack size included), so the two aren’t directly comparable.
Period
Total Part D spend
$641.1K
Claims incl. refills
82
Beneficiaries
29
Spend / beneficiary
$22,108.18
Spend / claim
$7,818.75
Trend by period
💵 About the dollar figures: spending is what Part D plans paid before confidential manufacturer rebates, so the program’s real net cost is lower. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part D Spending by Drug (data.cms.gov), updated quarterly.

Reported adverse events (FAERS)

Read carefully: FAERS reports are voluntary and unverified. Counts are not incidence, do not establish causation, are subject to reporting bias, and cannot be used to compare one drug to another. Shown for signal context only. Reports for Sodium Phenylbutyrate — the ingredient across all brands.

Top reported reactions

Hyperammonaemia56
Vomiting42
Death35
Ammonia Increased32
Nausea28
Diarrhoea27
Decreased Appetite25

Age at onset

Neonate10
Infant31
Child36
Adolescent21
Adult57
Elderly8

Reporter sex

420 reports
Male · 43%
Female · 56%
Unknown · 1%

Serious outcomes

Hospitalization164
Death84
Life-threatening13
Reports over time (by year) — tap or hover for the count & year
2019 2021 2023 2026 40 0
Most recent year is provisional (FAERS lags ~3 months).
Where does this data come from?
Adverse-event reports from the FDA Adverse Event Reporting System (FAERS) via openFDA. FAERS reports are voluntary and unverified — counts are not incidence and don’t establish causation.

About this NDC listing & data coverage

Finished prescription product No longer marketed (per FDA listing data)
What data is (and isn’t) available for this NDC — tap to expand
NDC identity (package / product / labeler codes) ✓ Available
Labeler ✓ Available
Product & package description ✓ Available
Marketing category & status ✓ Available
Active ingredient / dosage form / route ✓ Available
FDA label (SPL via DailyMed) ✓ Available
Package photos — Not published for this NDC No photo available yet for this listing.
Inactive ingredients (structured) — Not published for this NDC The labeler did not submit a structured excipient list, or no SPL is available.
NADAC pharmacy acquisition price (CMS) — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey.
Orange Book / therapeutic-equivalence data — Not published for this NDC Applies only to products approved under an NDA/ANDA; many listings are out of scope.
HCPCS J-code billing crosswalk — Not published for this NDC Most self-administered / retail products have no J-code — that is normal.
Medicaid utilization (CMS SDUD) — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold.
“Not published” reflects what the public FDA / CMS / NLM sources provide for this exact package code — it is a property of the data feeds, not a judgment about the product.

Questions about this listing

Why is there no price listed?
The pricing shown on our NDC pages comes from CMS NADAC, a voluntary survey of retail community pharmacy invoices. CMS does not publish a NADAC for every NDC — packages outside the retail survey (institutional and hospital products, bulk packages, discontinued items, and many OTC items) may never receive one. A missing price reflects the survey's scope, not this product's actual cost, and does not mean the product is free or unavailable.
What does the discontinued status mean for this NDC?
The labeler reported a marketing end date (or the listing was delisted), so this specific package is no longer actively marketed. Remaining stock may still be dispensed for a time, and the NDC stays valid for historical records and claims — but data feeds (pricing, labeling) typically stop updating for it. Other package sizes or other manufacturers' versions of the same medication may still be marketed — see the equivalents section where available.
Is the NDC printed on the package the same as the 11-digit billing NDC?
Yes, they identify this exact package in different formats. The form printed on the packaging and shown on DailyMed is the one the FDA registered. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero and the dashes are dropped. The Identity section at the top of this page lists each form of this code.
Who lists this product with the FDA?
Sigmapharm Laboratories, LLC is the labeler of record for this NDC — the company under whose FDA-assigned code the package is listed. The labeler may be the manufacturer itself or a distributor marketing the product under its own code.
Do I need a prescription for this product?
This NDC is listed with FDA as a prescription product, so it is dispensed under a prescriber's order. Your pharmacist can tell you whether any over-the-counter forms of the same medication exist.
This page identifies an FDA-listed package (the NDC) and reports public regulatory and pricing data about the listing. It is reference information, not a medical recommendation — talk to your pharmacist or prescriber about your own medication.
Where does this data come from?
Listing facts (marketing category, packager status, marketing dates) from the FDA openFDA NDC Directory; label availability from DailyMed; pricing coverage from CMS NADAC; equivalence scope from the FDA Orange Book.
← 42794-0083-08 · Sigmapharm 42794-0131-02 · SIGMAPHARM →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.