Glycerol Phenylbutyrate
Glycerol Phenylbutyrate is a nitrogen-binding agent used for the chronic management of urea cycle disorders (UCDs). It provides an alternative pathway for nitrogen excretion, helping to prevent toxic ammonia accumulation in patients with inherited deficiencies of urea cycle enzymes or transporters. This medication is typically used when dietary protein restriction alone is insufficient to control hyperammonemia.
Glycerol Phenylbutyrate treats urea cycle disorders by providing an alternative route for nitrogen removal to prevent dangerous ammonia buildup.
Key facts at a glance
- ATC
- A16AX09
- RxNorm
- 1368451
- Generic
- Glycerol Phenylbutyrate
- Class
- atc-a16
- Brands
- Ravicti
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- solution
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Chronic management of hyperammonemia in patients with urea cycle disorders (UCDs), including deficiencies of carbamoyl phosphate synthetase I, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinate lyase, arginase, and N-acetylglutamate synthetase. Used when dietary protein restriction and amino acid supplementation are insufficient.
Glycerol Phenylbutyrate is a prodrug that is metabolized by pancreatic lipases to phenylbutyrate, which then conjugates with glutamine to form phenylacetylglutamine. This conjugate is readily excreted in urine, providing an alternative pathway for nitrogen disposal that bypasses the defective urea cycle, thereby reducing ammonia levels in the blood and brain.
Must be used with dietary protein restriction and may require supplemental amino acids. Requires careful monitoring of ammonia levels. Common side effects may include gastrointestinal symptoms. Use with caution in patients with hepatic or renal impairment. Not indicated for acute hyperammonemic crises requiring immediate ammonia-lowering interventions.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy