Based on 1 source · Recall-safety score from FDA recall history — this product's own recalls and its manufacturer's record. Not an efficacy or quality rating. methodology →
Key facts
- Active ingredient
- Glycerol Phenylbutyrate
- Form
- Liquid
- Strength
- Glycerol Phenylbutyrate 1.1GM/ML
- Type
- Prescription (Rx)
- Brand or generic
- Generic
- Manufacturer
- Teva
- FDA application
- ANDA218738
What is Glycerol Phenylbutyrate?
From the FDA label:Glycerol phenylbutyrate oral liquid is a clear, colorless to pale yellow oral liquid. It is insoluble in water and most organic solvents, and it is soluble in dimethylsulfoxide (DMSO) and greater than 65% acetonitrile. Glycerol phenylbutyrate is a nitrogen-binding agent. It is a triglyceride containing 3 molecules of PBA linked to a glycerol backbone, the chemical name of which is benzenebutanoic acid, 1', 1' ' –(1,2,3-propanetriyl) ester with a molecular weight of 530.65. It has a molecular formula of C 33 H 38 O 6 . The structural formula is: structure
How to use
Glycerol phenylbutyrate oral liquid should be prescribed by a physician experienced in management of UCDs. For administration and preparation, see full prescribing information. ( 2.1 , 2.6 ) Switching From Sodium Phenylbutyrate Tablets or Powder to Glycerol Phenylbutyrate Oral Liquid: Patients should receive the dosage of glycerol phenylbutyrate oral liquid that contains the same amount of phenylbutyric acid, see full prescribing information for conversion. ( 2.2 ) Initial Dosage in Phenylbutyrate-Naïve Patie nts ( 2.3 ): Recommended dosage range is 4.5 to 11.2 mL/m 2 /day (5 to 12.4 g/m 2 /day). For patients with some residual enzyme activity not adequately controlled with dietary restriction, the recommended starting dose is 4.5 mL/m 2 /day. Take into account patient's estimated urea synthetic capacity, dietary protein intake, and diet adherence. Dosage Adjustment and Monitoring: Follow plasma ammonia levels to determine the need for dosage titration. ( 2.4 ) Dosage Modifications in Patients with Hepatic Impairment: Start dosage at lower end of range. ( 2.5 , 8.7 ) 2.1 Important Administration Instructions Glycerol phenylbutyrate oral liquid should be prescribed by a physician experienced in the management of UCDs. Instruct patients to take glycerol phenylbutyrate oral liquid with food or formula and to administer directly into the mouth via oral syringe. Instruct patients…
Side effects
The following clinically significant adverse reactions are described elsewhere in the labeling: Neurotoxicity [see Warnings and Precautions ( 5.1 )] Pancreatic insufficiency or Intestinal Malabsorption [see Warnings and Precautions ( 5.2 )] Most common adverse reactions (≥10%) in adults are: diarrhea, flatulence, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Teva at 1-888-838-2872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Assessment of adverse reactions was based on exposure of 45 adult patients (31 female and 14 male) with UCD subtype deficiencies of ornithine transcarbamylase (OTC, n=40), carbamoyl phosphate synthetase (CPS, n=2), and argininosuccinate synthetase (ASS, n=1) in a randomized, double-blind, active-controlled (glycerol phenylbutyrate oral liquid vs sodium phenylbutyrate), crossover, 4-week study (Study 1) that enrolled patients 18 years of age and older [see Clinical Studies ( 14.1 )] . One of the 45 patients received only sodium phenylbutyrate prior to withdrawing on day 1 of the study due to an adverse reaction. The most common…
Warnings
Important safety information
Neurotoxicity : Phenylacetate (PAA), the active moiety of glycerol phenylbutyrate oral liquid, may be toxic; reduce dosage for symptoms of neurotoxicity. ( 5.1 ) Pancreatic Insufficiency or Intestinal Malabsorption : Monitor ammonia levels closely. ( 5.2 ) 5.1 Neurotoxicity Increased exposure to PAA, the major metabolite of glycerol phenylbutyrate oral liquid, may be associated with neurotoxicity in patients with UCDs. In a study of adult cancer patients, subjects received sodium phenylacetate administered as a 1-hour infusion twice daily at two dose levels of 125 and 150 mg/kg for a 2-week period. Of 18 subjects enrolled, 7 had a history of primary central nervous system tumor. Signs and symptoms of potential PAA neurotoxicity, which were reversible, were reported at plasma PAA concentrations above 500 micrograms/mL and included somnolence, fatigue, lightheadedness, headache, dysgeusia, hypoacusis, disorientation, impaired memory, and exacerbation of preexisting neuropathy. PAA concentrations were not measured when symptoms resolved. In healthy subjects, after administration of 4 mL and 6 mL glycerol phenylbutyrate oral liquid 3 times daily (13.2 g/day and 19.8 g/day, respectively) for 3 days, a dose-dependent increase in non-serious nervous system adverse reactions were observed. In subjects who had nervous system adverse reactions, plasma PAA concentrations, which were measured on Day 3 per protocol and not always at onset of symptoms, ranged from 8 to 56 micrograms/mL with 4 mL glycerol phenylbutyrate oral liquid 3 times daily and from 31 to 242 micrograms/mL with 6 mL glycerol phenylbutyrate oral liquid 3 times daily. In clinical trials in patients with UCDs who had been on sodium phenylbutyrate prior to administration of glycerol phenylbutyrate oral liquid, adverse reactions of headache, fatigue, symptoms of peripheral neuropathy, seizures, tremor and/or dizziness were reported. No correlation between plasma PAA concentration and neurologic symptoms was identified but plasma PAA concentrations were generally not consistently measured at the time of neurologic symptom occurrence [see Clinical Pharmacology ( 12.3 )] . If symptoms of vomiting, nausea, headache, somnolence or confusion are present in the absence of high ammonia or other intercurrent illness which explains these symptoms, consider the potential for PAA neurotoxicity which may need reduction in the glycerol phenylbutyrate oral liquid dosage [see Dosage and Administration ( 2.4 )] . 5.2 Pancreatic Insufficiency or Intestinal Malabsorption Exocrine pancreatic enzymes hydrolyze glycerol phenylbutyrate oral liquid in the small intestine, separating the active moiety, phenylbutyrate, from glycerol. This process allows phenylbutyrate to be absorbed into the circulation. Low or absent pancreatic enzymes or intestinal disease resulting in fat malabsorption may result in reduced or absent digestion of glycerol phenylbutyrate oral liquid and/or absorption of phenylbutyrate and reduced control of plasma ammonia. Monitor ammonia levels closely in patients with pancreatic insufficiency or intestinal malabsorption.
Who should not take Glycerol Phenylbutyrate
Glycerol phenylbutyrate oral liquid is contraindicated in patients with known hypersensitivity to phenylbutyrate. Signs of hypersensitivity include wheezing, dyspnea, coughing, hypotension, flushing, nausea, and rash. Known hypersensitivity to phenylbutyrate. ( 4 )
Overdose — what happens if you take too much
While there is no experience with overdosage in human clinical trials, PAA, a toxic metabolite of glycerol phenylbutyrate oral liquid, can accumulate in patients who receive an overdose [see Warnings and Precautions ( 5.1 )] . If over-exposure occurs, call your Poison Control Center at 1-800-222-1222 for current information on the management of poisoning or overdosage.
U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.
Interactions
Corticosteroids, valproic acid, or haloperidol : May increase plasma ammonia level; monitor ammonia levels closely. ( 7.1 ) Probenecid : May affect renal excretion of metabolites of glycerol phenylbutyrate oral liquid, including phenylacetylglutamine (PAGN) and PAA. ( 7.2 ) CYP3A4 Substrates with narrow therapeutic index (e.g., alfentanil, quinidine, cyclosporine) : Glycerol phenylbutyrate oral liquid may decrease exposure; monitor for decreased efficacy of the narrow therapeutic index drug. ( 7.3 ) Midazolam : Decreased exposure; monitor for suboptimal effect of midazolam. ( 7.3 ) 7.1 Potential for Other Drugs to Affect Ammonia Corticosteroids Use of corticosteroids may cause the breakdown of body protein and increase plasma ammonia levels. Monitor ammonia levels closely when corticosteroids and glycerol phenylbutyrate oral liquid are used concomitantly. Valproic Acid and Haloperidol Hyperammonemia may be induced by haloperidol and by valproic acid. Monitor ammonia levels closely when use of valproic acid or haloperidol is necessary in patients with UCDs. 7.2 Potential for Other Drugs to Affect Glycerol Phenylbutyrate Oral Liquid Probenecid Probenecid may inhibit the renal excretion of metabolites of glycerol phenylbutyrate oral liquid including PAGN and PAA. 7.3 Potential for Glycerol Phenylbutyrate Oral Liquid to Affect Other Drugs Drugs with narrow therapeutic index that are substrates of CYP3A4 Glycerol phenylbutyrate oral liquid is a weak inducer of CYP3A4 in humans. Concomitant use of glycerol phenylbutyrate oral liquid may decrease the systemic exposure to drugs that are substrates of CYP3A4. Monitor for decreased efficacy of drugs with narrow therapeutic index (e.g., alfentanil, quinidine, cyclosporine) [see Clinical Pharmacology ( 12.3 )] . Midazolam Concomitant use of glycerol phenylbutyrate oral liquid decreased the systemic exposure of midazolam. Monitor for suboptimal effect of midazolam in patients who are being treated with glycerol phenylbutyrate oral liquid.
Storing Glycerol Phenylbutyrate, and how long it keeps
Quoted from this product’s own FDA label. Storage belongs to the product and its device, not to the drug in general — a pen and a tablet of the same medicine are kept completely differently.
- “Discard bottle 28 days after opening.”
- “Discard bottle and any remaining contents 28 days after opening.”
- “O Throw away the bottle and any unused glycerol phenylbutyrate oral liquid 28 days after opening.”
- “Store glycerol phenylbutyrate oral liquid between 68ºF to 77ºF (20°C to 25°C).”
Dosage forms
Liquid
The forms currently marketed in the U.S., per the FDA National Drug Code Directory.
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Frequently asked questions
- How is Glycerol Phenylbutyrate rated?
- pharmaranks gives Glycerol Phenylbutyrate a composite score of 2.8 out of 5, currently based on 1 weighted source (FDA regulatory recall-safety data weighted highest). See our methodology at /how-we-rate.
- Is there a coupon or discount for Glycerol Phenylbutyrate?
- pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Glycerol Phenylbutyrate. To pay less, Glycerol Phenylbutyrate is already a generic — usually the lowest-cost version — so the main levers are comparing cash prices between pharmacies and using a pharmacy discount-card service. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
- Who makes Glycerol Phenylbutyrate?
- Glycerol Phenylbutyrate is marketed by Teva. You can see Teva's full profile, rating, and other products on pharmaranks.
- Is Glycerol Phenylbutyrate a brand-name or generic drug?
- Glycerol Phenylbutyrate is a generic medication; its active ingredient is Glycerol Phenylbutyrate. Generics contain the same active ingredient as the brand-name original and are usually lower cost.
- Is Glycerol Phenylbutyrate available over the counter?
- No. Glycerol Phenylbutyrate is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
- What forms does Glycerol Phenylbutyrate come in?
- Glycerol Phenylbutyrate is currently marketed as liquid, per the FDA's National Drug Code Directory.
- Is Glycerol Phenylbutyrate FDA-registered?
- Glycerol Phenylbutyrate is on record with the U.S. FDA under application number ANDA218738. You can verify this on its official FDA label.
- Has Glycerol Phenylbutyrate been recalled by the FDA?
- Glycerol Phenylbutyrate has no FDA recalls recorded under its own application in the openFDA enforcement database. Its recall-safety score reflects its manufacturer's overall recall record. This is general reference, not medical advice — check the FDA recall database for the latest alerts.
- Is Glycerol Phenylbutyrate safe?
- There's no single safe-or-not verdict. pharmaranks gives Glycerol Phenylbutyrate a recall-safety score of 56/100, based on its FDA recall history (no recalls under its own FDA application) — not an efficacy or side-effect rating. Review its FDA-label side effects and warnings before use, and always consult a licensed professional.
- What are the side effects of Glycerol Phenylbutyrate?
- Glycerol Phenylbutyrate's side effects are taken directly from its FDA label. From the label: The following clinically significant adverse reactions are described elsewhere in the labeling: Neurotoxicity [see Warnings and Precautions ( 5.1 )] Pancreatic insufficiency or Intestinal Malabsorption [see Warnings and Precautions ( 5.2 )] Most common adverse reactions (≥10%) in adults are: diarrhe… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.
Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.
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glycerol phenylbutyrate
56/100