Benzoate / Phenylacetate
Sodium benzoate and sodium phenylacetate is a combination medication used to treat chronic hyperammonemia (elevated blood ammonia levels) in patients with urea cycle disorders. These genetic disorders impair the body's ability to convert ammonia into urea for excretion. This medication provides an alternative pathway for nitrogen removal by conjugating with amino acids and eliminating them through urine.
Combination therapy for managing chronic high ammonia levels in patients with urea cycle disorders.
Key facts at a glance
- RxNorm
- 1008811
- Generic
- Benzoate / Phenylacetate
- Class
- multi-ingredient
- Brands
- Ammonul
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- 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 associated with urea cycle disorders, including carbamoyl phosphate synthetase deficiency, ornithine transcarbamylase deficiency, citrullinemia, and argininosuccinic aciduria.
Sodium benzoate conjugates with glycine to form hippuric acid, while sodium phenylacetate conjugates with glutamine to form phenylacetylglutamine—both compounds are excreted in urine, providing an alternative route for nitrogen elimination when the urea cycle is defective.
Must be used alongside dietary protein restriction. May cause gastrointestinal side effects, drowsiness, or dizziness. Requires regular monitoring of ammonia and amino acid levels. Should be administered under close medical supervision as part of a comprehensive treatment program.
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 August 28, 2026. · Read our editorial policy