Glycerol Phenylbutyrate
Glycerol phenylbutyrate is an oral liquid used to help manage urea cycle disorders (UCDs), rare inherited conditions that cause dangerous ammonia buildup in the blood.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 9 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Glycerol Phenylbutyrate: Patient Information Guide
A plain-language walkthrough of Glycerol Phenylbutyrate — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Glycerol phenylbutyrate oral liquid is used to help manage a group of rare inherited conditions called urea cycle disorders (UCDs).
- Ravicti (glycerol phenylbutyrate oral liquid) is indicated for the chronic (ongoing, long-term) management of UCDs in patients who cannot be adequately controlled by dietary protein restriction and/or amino acid supplementation alone.
- Glycerol phenylbutyrate oral liquid (generic) carries the same indication for chronic UCD management.
- Both products must be used in combination with dietary protein restriction and, when appropriate, supplements such as essential amino acids, arginine, citrulline, or protein-free calorie supplements.
- Neither product is for treating acute hyperammonemia — a sudden, life-threatening spike in blood ammonia that requires faster-acting emergency interventions.
- Safety and effectiveness for N-acetylglutamate synthase (NAGS) deficiency have not been established for either product.
⚙️How it works▾
In urea cycle disorders, the body is missing an enzyme or transporter needed to convert ammonia into urea, so ammonia builds up to toxic levels. Glycerol phenylbutyrate acts as a nitrogen-binding agent — it gives the body a different way to get rid of excess nitrogen. After you swallow it, digestive enzymes release phenylbutyric acid (PBA), which is then converted to phenylacetate (PAA) — the part that actually does the work. PAA binds to glutamine (an amino acid that carries nitrogen) in the liver and kidneys, forming a compound called phenylacetylglutamine (PAGN). PAGN carries two nitrogen atoms — the same as urea — and is flushed out safely through the urine, reducing the toxic ammonia load.
💊How it's taken▾
Glycerol phenylbutyrate oral liquid is taken by mouth, typically three times daily in adults and older children, and three or more times daily in children under two years of age. It should always be taken with food or formula. The dose is based on body surface area and is carefully adjusted based on blood ammonia levels and dietary protein intake — your prescriber will determine the right amount for you or your child.
- Use the provided oral syringe to measure and give each dose directly into the mouth.
- For infants who are breastfeeding, the dose should be given just before breastfeeding.
- Patients who cannot swallow can receive it through a nasogastric (NG) tube or gastrostomy (G-tube) under medical supervision.
- Always follow your prescriber's exact instructions; never adjust the dose on your own.
🤒Side effects — in detail▾
The most common side effects seen in adults taking glycerol phenylbutyrate oral liquid include:
- Diarrhea
- Flatulence (gas)
- Headache
- Nausea or vomiting
- Decreased appetite
- Fatigue
- Stomach (abdominal) pain
- Dizziness
In younger children and infants, additional reported side effects include rash, constipation, fever, cough, nasal congestion, and in very young infants, changes in blood counts (such as neutropenia or thrombocytopenia). More serious reactions — including signs of neurotoxicity such as confusion, unusual sleepiness, or memory problems — should be reported to your doctor right away, as a dose reduction may be needed.
⚠️Warnings & precautions▾
- Neurotoxicity (nerve side effects): The active metabolite PAA can build up and cause symptoms like headache, sleepiness, confusion, dizziness, memory problems, and abnormal sensations. If these occur without a clear cause (like high ammonia or illness), contact your doctor — a dose reduction may be needed.
- Pancreatic insufficiency or fat malabsorption: This medication relies on digestive enzymes in the gut to release its active ingredient. If you have a condition that reduces those enzymes or causes fat malabsorption, less medication may be absorbed, and ammonia control could be inadequate. Ammonia levels need closer monitoring.
- Liver impairment: The liver converts PAA into the final waste product. Liver disease can slow this process, causing PAA to accumulate to higher, potentially toxic levels. Start at a lower dose and monitor carefully.
- Acute hyperammonemia: Glycerol phenylbutyrate is not fast enough to treat a sudden dangerous spike in ammonia — emergency treatment is required in those situations.
🔀What it interacts with▾
Several medications can affect how well glycerol phenylbutyrate works, or be affected by it:
- Corticosteroids (steroid medicines): Can break down body protein and raise ammonia levels — monitor ammonia closely if you need steroids.
- Valproic acid (a seizure and mood medicine): Can raise ammonia levels on its own — extra monitoring is needed if you take both.
- Haloperidol (an antipsychotic): Can also raise ammonia — monitor closely if combined.
- Probenecid (used for gout): May slow the kidneys from clearing the active metabolites (PAGN and PAA), potentially causing them to build up.
- CYP3A4-metabolized drugs with a narrow therapeutic index (e.g., alfentanil, quinidine, cyclosporine): Glycerol phenylbutyrate can weakly activate the liver enzyme CYP3A4, potentially reducing the effectiveness of these medications — tell your prescriber about all your medicines.
- Midazolam (a sedative): Levels of midazolam may be reduced — watch for it being less effective than expected.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Allergy: Do not take if you have a known allergy (hypersensitivity) to phenylbutyrate — signs include wheezing, difficulty breathing, low blood pressure, flushing, nausea, or rash.
- Pregnancy: Human data are very limited. Animal studies at high doses showed some effects on fetal development. Report any pregnancy to Teva at 1-888-838-2872.
- Breastfeeding: Breastfeeding is not recommended during treatment due to potential risks of neurotoxicity and other serious effects in a breastfed infant.
- Children: Safety and effectiveness have been established in patients from newborn age and older; dosing differs by age and must be guided by a specialist.
- Older adults (65+): Limited clinical trial data in this age group; start at the lower end of the dosing range due to a greater likelihood of reduced liver, kidney, or heart function.
- Liver (hepatic) impairment: Start at a lower dose; monitor PAA levels and ammonia carefully, as the liver's ability to clear PAA may be reduced.
- Kidney (renal) impairment: Safety and efficacy are not fully established; monitor ammonia levels closely.
- Pancreatic insufficiency or fat malabsorption: These conditions may reduce how much active drug is absorbed — close ammonia monitoring is essential.
🚑If you take too much▾
There is no human clinical experience with overdose of glycerol phenylbutyrate oral liquid. Taking too much could cause the active metabolite PAA to build up to toxic levels, potentially causing serious neurological (brain and nerve) side effects. If you suspect an overdose, call Poison Control immediately at 1-800-222-1222.
📡Pharmacodynamics — effects in the body▾
In clinical studies, glycerol phenylbutyrate oral liquid controlled blood ammonia levels comparably to sodium phenylbutyrate (an older related medication) when patients were switched from one to the other. Studies in healthy volunteers also showed that at the doses studied, glycerol phenylbutyrate oral liquid did not meaningfully affect the heart's electrical rhythm (specifically, the QTc interval — a measure of heart-rhythm safety) — the observed changes were well within the accepted safety threshold.
🔬Pharmacokinetics — how your body processes it▾
After swallowing, glycerol phenylbutyrate is broken down by pancreatic enzymes in the gut, releasing phenylbutyric acid (PBA). PBA is then converted through a process called beta-oxidation into phenylacetate (PAA), which is the active component. PAA binds to glutamine in the liver and kidneys to form phenylacetylglutamine (PAGN), which is then excreted in the urine. In fasting healthy adults, peak blood levels of the key components appear within 2 to 4 hours of a single dose; in UCD patients taking multiple doses daily, peak levels occur later in the day. Younger children — especially newborns — tend to have higher peak PAA concentrations than older children and adults at similar doses. About 69% of the administered dose is eventually cleared from the body as PAGN in the urine.
📦How to store it▾
Store at 20°-25°C (68°-77°F) with excursions permitted to 15°-30°C (59°-86°F).
📄 Written from Glycerol Phenylbutyrate’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Glycerol Phenylbutyrate
17 supplements and herbal products have documented interactions with Glycerol Phenylbutyrate in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 7
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Glycerol Phenylbutyrate — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is this medication for, and why does my child need it? ▾
How should I give this medicine — is there a special technique? ▾
What side effects are most common and which ones should I call the doctor about? ▾
Are there any other medicines I need to be careful about while taking this? ▾
Is it safe to take during pregnancy or while breastfeeding? ▾
What happens if a dose is missed or too much is taken by accident? ▾
Is Glycerol Phenylbutyrate available over the counter? ▾
When was Glycerol Phenylbutyrate first available? ▾
Who makes Glycerol Phenylbutyrate? ▾
💬 Answers drafted from Glycerol Phenylbutyrate’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Glycerol Phenylbutyrate comes
Glycerol Phenylbutyrate is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Oral solution
How this form is used
- Ravicti oral liquid is indicated for chronic management of urea cycle disorders (UCDs) in patients who cannot be controlled by dietary protein restriction and/or amino acid supplementation alone
- Glycerol phenylbutyrate oral liquid is indicated for chronic management of UCDs in patients who cannot be controlled by dietary protein restriction and/or amino acid supplementation alone
- Both products must be used alongside dietary protein restriction and, when needed, dietary supplements such as essential amino acids, arginine, or citrulline
- Neither product is indicated for treatment of acute hyperammonemia (a sudden dangerous spike in ammonia)
- Ravicti and glycerol phenylbutyrate oral liquid should be taken with food or formula, drawn up with an oral syringe, and given directly into the mouth
- Use a new, dry oral syringe for each dose and discard it after use; use a new reclosable bottle cap adapter with each new bottle
- Discard the bottle and any remaining contents 28 days after opening; do not use the liquid if it appears cloudy
- For patients who cannot swallow, Ravicti and glycerol phenylbutyrate oral liquid can be given through a nasogastric tube or gastrostomy tube as directed by a physician
📊 Glycerol Phenylbutyrate across the U.S. market
How Glycerol Phenylbutyrate appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (3) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Glycerol Phenylbutyrate is used
A general measure of how commonly Glycerol Phenylbutyrate is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Glycerol Phenylbutyrate is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Glycerol Phenylbutyrate prescribed? Of the 1,597 medications we measure, Glycerol Phenylbutyrate ranks #1,094 by Medicaid prescriptions — more than 31% of them.
Utilization by Glycerol Phenylbutyrate product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
glycerol phenylbutyrate 1100 MG/ML Oral Solution
Summed across the 2 of 10 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1368453
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Glycerol Phenylbutyrate, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 2 of 10 listed Glycerol Phenylbutyrate NDCs with Medicaid activity.
🔍 Compare Glycerol Phenylbutyrate products
A representative set of FDA-listed product records for Glycerol Phenylbutyrate — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Oral solution | ||||
| 1.1 g/mL | Oral | Aurobindo Pharma Limited | ANDA | View NDC → |
| 1 kg/kg | — | Aurobindo Pharma Limited | BULK INGREDIENT | View NDC → |
| 1.1 g/mL | Oral | Camber Pharmaceuticals, Inc. | ANDA | View NDC → |
| 1 kg/kg | — | HAS Healthcare Advanced Synthesis SA × 2 listings | BULK INGREDIENT | View NDC → |
| 1.1 g/mL | Oral | Horizon Therapeutics, Inc. | NDA | View NDC → |
| 1.1 g/mL | Oral | Horizon Therapeutics USA, Inc. × 2 listings | NDA | View NDC → |
| 1 kg/kg | — | Lupin Manufacturing Solutions Limited | BULK INGREDIENT | View NDC → |
| 1.1 g/mL | Oral | Lupin Pharmaceuticals, Inc. | NDA | View NDC → |
| 1 kg/kg | — | MSN Laboratories Private Limited | BULK INGREDIENT | View NDC → |
| 1.1 g/mL | Oral | Navinta LLC | ANDA | View NDC → |
| 1.1 g/mL | Oral | Novadoz Pharmaceuticals LLC | ANDA | View NDC → |
| 35 kg/35 kg | — | Nuray Chemicals Private Limited | BULK INGREDIENT | View NDC → |
| 1.1 g/mL | Oral | Par Health USA, LLC | ANDA | View NDC → |
| 1.1 g/mL | — | Penn Pharmaceutical Services Limited | DRUG FOR FURTHER PROCESSING | View NDC → |
| 1.1 g/mL | Oral | Teva Pharmaceuticals, Inc. | ANDA | View NDC → |
| 1.1 g/mL | Oral | Zydus Pharmaceuticals USA Inc. | ANDA | View NDC → |
| 💊Bulk drug substance | ||||
| 4.999 kg/4.999 kg | — | Apothecon Pharmaceuticals Pvt Ltd | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Hetero Drugs Limited | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Patheon Austria GmbH & CoKG | BULK INGREDIENT | View NDC → |
Showing 21 of 21 products — FDA National Drug Code Directory. See every product, package size and price: browse all 21 Glycerol Phenylbutyrate NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Glycerol Phenylbutyrate — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Glycerol Phenylbutyrate in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Glycerol Phenylbutyrate went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1368451 1 dose form · 1 strength
-
Dose form (SCDF) Oral Solution RxCUI 2106748In current FDA listingsClinical drug / strength (SCD) 1100 MG/MLRxCUI 1368453
Look up RxCUI 1368451 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Glycerol Phenylbutyrate is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Glycerol Phenylbutyrate belongs to the Various alimentary tract and metabolism products class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 9 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Lupin Pharmaceuticals, Inc. is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.