Glycerol Phenylbutyrate Oral Liquid shortage
Glycerol Phenylbutyrate Oral Liquid is currently listed in shortage by the FDA. The FDA lists 2 affected products. This page was last refreshed from FDA data on Sep 24, 2026.
Amgen is permanently stopping its version of glycerol phenylbutyrate oral liquid (1.1 g/mL). Other makers — including Teva, Camber, Par Health USA, and Aurobindo — still list this same medicine as available.
Don’t stop or change your therapy on your own — talk with your prescriber about the plan that fits you, and ask your pharmacist what’s actually available (see options).
Do you take this drug? See the ‘What to do’ recommendation from Dr. Brian Staiger, PharmD →What’s in shortage — at a glance
These figures count only the manufacturers that reported this shortage to the FDA — not every company that makes Glycerol Phenylbutyrate Oral Liquid. Other makers that haven’t reported a problem are shown in the green card below.
Shortage timeline
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Sep 1, 2026Currently in shortage2 of 2 products affected.
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Sep 1, 2026First reported to the FDA2 products first listed.
Built from FDA posting and update dates. The end date FDA publishes is the posting/update date, not a true resolution date, so durations are approximate.
What exactly is on backorder — by manufacturer
Manufacturer: Amgen Inc. 📞 800-772-6436 2 NDCS click to expand
| Status | NDC / product | Strength | Availability | Related information | Reason |
|---|---|---|---|---|---|
| To Be Discontinued | RAVICTI, Oral Liquid, 1.1 g/1 mL (NDC 75987-050-06) | — | — | Discontinuation in the manufacturing of the drug product | — |
| To Be Discontinued | RAVICTI, Oral Liquid, 1.1 g/1 mL (NDC 75987-050-07) | — | — | Discontinuation in the manufacturing of the drug product | — |
These rows are manufacturer reports to the FDA for Glycerol Phenylbutyrate Oral Liquid — they do not necessarily cover every manufacturer that makes this drug. A company appears here only if it told the FDA it has a supply problem, so other makers may still have stock. That’s the basis for the Where else can I get Glycerol Phenylbutyrate Oral Liquid? options further down this page.
Why is Glycerol Phenylbutyrate Oral Liquid in shortage?
Amgen has reported to the FDA that it is permanently stopping the manufacturing of Ravicti (glycerol phenylbutyrate) oral liquid, 1.1 g/1 mL. This applies to both package sizes listed under this report (NDC 75987-050-07 and NDC 75987-050-06). No specific reason for this decision was shared publicly — Amgen simply noted that manufacturing of this product is being discontinued.
It's worth knowing that this report reflects only what Amgen has filed with the FDA. It does not mean the medication is disappearing from every manufacturer or source — other makers may be listed separately on the FDA's shortage page.
Based on the manufacturer-reported reason(s) and notes on file with the FDA for Glycerol Phenylbutyrate Oral Liquid, summarized in plain English by HelloPharmacist. A drug can be short for more than one reason, and the FDA updates these as manufacturers report changes.
What should I do if I take Glycerol Phenylbutyrate Oral Liquid?
Glycerol phenylbutyrate oral liquid is currently on the FDA shortage list. I know this can feel unsettling when it is a medicine you rely on, so let me walk you through what the data shows and the steps that make the most sense.
The only strength involved is the 1.1 g/1 mL oral liquid, and right now the manufacturer that filed this report (Amgen, for its RAVICTI product) shows no available source. This is listed as a discontinuation, meaning the maker is stopping production of that product. Because of that, this particular supply problem may be a lasting one rather than a short delay — which makes talking with your prescriber the right next step. It helps to know, though, that the same medicine at the same 1.1 g/mL strength is also listed from several other makers, so it may still be obtainable.
Here is what I suggest, in order:
- Do not stop, skip, or change your dose on your own.
- Ask your pharmacy to source glycerol phenylbutyrate 1.1 g/mL from another maker (options include Teva, Camber, Par Health, Aurobindo, Lupin, and Novadoz); it may not be in local stock, but they can check wholesalers.
- If it cannot be found, ask your prescriber or pharmacist about the best path forward.
Manufacturer contact numbers are listed on this page for reference; pharmacies usually handle those calls. This is national, manufacturer-reported data and may not match your local pharmacy's shelf.
- Don’t stop or change the medication on your own — talk to your prescriber first.
- If this is part of an ongoing or essential regimen (for example HIV treatment or prevention, seizure, heart, transplant, diabetes or mental-health medicines), do not skip or ration doses — contact your pharmacist or prescriber right away to arrange continued supply before you run out.
- Ask your pharmacy to check other manufacturers, strengths, package sizes, and nearby stores.
- Ask your prescriber whether a different strength, formulation, or the brand/generic version is appropriate.
Uses, dosing, side effects, prices, and the complete FDA label — written in plain English and pharmacist-reviewed.
Where else can I get Glycerol Phenylbutyrate Oral Liquid?
FDA shortages are manufacturer-reported — a company only shows up on the shortage list if it told the FDA it has a supply problem, so not every maker of Glycerol Phenylbutyrate Oral Liquid is necessarily short. Below we pull together the other still-marketed options that are not reported in shortage: the same medicine from manufacturers that haven’t reported a problem, and alternative dosage forms. These may still be out of stock at your pharmacy, and only your prescriber or pharmacist can decide what’s right for you.
Same medicine, other manufacturers (not reported short)
Same active ingredient, dosage form & route as the shortage (matched on the FDB HICL ingredient code), from makers that have not filed a shortage with the FDA:
| Product | Strength | Form / route | Manufacturer | NDC |
|---|---|---|---|---|
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Teva Pharmaceuticals, Inc. | 00480-3777-58 |
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Camber Pharmaceuticals, Inc. | 31722-0605-31 |
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Par Health USA, LLC | 49884-0264-95 |
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Aurobindo Pharma Limited | 59651-0988-25 |
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Lupin Pharmaceuticals, Inc. | 70748-0425-01 |
| Glycerol Phenylbutyrate | GLYCEROL PHENYLBUTYRATE 1.1 g/mL | Liquid · Oral | Novadoz Pharmaceuticals LLC | 72205-0331-57 |
Therapeutic equivalents & pricing 10 productsclick to expand
Orange Book–rated equivalents of the affected strengths, with the latest NADAC price (a federal retail-acquisition benchmark, not your copay) and an evidence-based availability label. Cheapest first.
| Product | Manufacturer | Package | NADAC $/unit | AB rating | Availability |
|---|---|---|---|---|---|
| Glycerol phenylbutyrate 1.1 g/mL | Teva | 1 bottle | — | AA | FDA listed |
| Glycerol Phenylbutyrate 1.1 g/mL | Camber | 1 bottle | — | AA | FDA listed |
| Glycerol Phenylbutyrate 1.1 g/mL | Par | 1 bottle | — | AA | FDA listed |
| Glycerol Phenylbutyrate 1.1 g/mL | Aurobindo | 1 bottle | — | AA | FDA listed |
| Glycerol Phenylbutyrate 1.1 g/mL | Zydus | 1 bottle | — | AA | FDA listed |
| glycerol phenylbutyrate 1.1 g/mL | Lupin | 1 bottle | — | AA | FDA listed |
| Glycerol phenylbutyrate 1.1 g/mL | Novadoz | 1 bottle | — | AA | FDA listed |
| Ravicti 1.1 g/mL | Horizon | 1 bottle | — | AA | FDA listed |
| Glycerol Phenylbutyrate 1.1 g/mL | Navinta | 1 bottle | — | AA | FDA listed |
| Ravicti 1.1 g/mL | Horizon | 4 bottles | — | AA | FDA listed |
Equivalents share the same ingredient, strength, dosage form and route; an AB rating means the FDA considers them substitutable. NADAC is a national retail-pharmacy acquisition benchmark from CMS — not what you pay. Availability is inferred from recent pricing, not a stock check.
Other drugs in the same treatment class
These are different medicines — not other versions of Glycerol Phenylbutyrate Oral Liquid — that fall in the same broad treatment class (ammonia inhibitors) . They are not automatic substitutes: they can differ in how they work, dosing, effectiveness, side effects and what they’re approved to treat. Do not switch on your own. This list is for information only — ask your prescriber or pharmacist whether any of them is appropriate for you.
Identity & classification
Where does this data come from?
Glycerol Phenylbutyrate Oral Liquid shortage FAQs
Is Glycerol Phenylbutyrate Oral Liquid in shortage?
Which products are affected?
When will Glycerol Phenylbutyrate Oral Liquid be available again?
Can I still get Glycerol Phenylbutyrate Oral Liquid somewhere?
What should I do if I take Glycerol Phenylbutyrate Oral Liquid?
Still have a question about the Glycerol Phenylbutyrate Oral Liquid shortage?
Ask a pharmacist about this shortage →View Glycerol Phenylbutyrate Oral Liquid on the FDA drug-shortage database →
Where does this data come from?
/drug/shortages) — drug, manufacturer & contact, NDC/product, status, availability, reason, therapeutic category and posting/update dates. Current / To Be Discontinued = active; Resolved is kept for history. The Supply-Risk rating is assessed per active ingredient and adds the FDA NDC Directory (still-marketed manufacturers by ingredient & form); same-medicine and equivalent products use First Databank classification + CMS NADAC pricing; Medicaid use + most-affected states come from CMS Medicaid State Drug Utilization Data. Reference only — confirm current status with the manufacturer or FDA before acting on it.