What are the side effects of Ammonul (sodium phenylacetate / sodium benzoate)?

The most common side effects of Ammonul (sodium phenylacetate / sodium benzoate) are vomiting, high blood sugar, [low potassium](https://medlineplus.gov/ency/article/000479.htm), involuntary muscle contractions, and problems with thinking.

sodium phenylacetate/sodium benzoate

Q: What is a urea cycle disorder (UCD)?

[Urea cycle disorders (UCDs)](https://www.ncbi.nlm.nih.gov/books/NBK482363/) are rare, genetic conditions that are passed down from members of your family. UCDs affect about 1 in 35,000 births in the U.S. They happen when proteins that turn ammonia into a waste product called urea either don't work correctly or are missing. This leads to a toxic buildup of ammonia in the blood. Symptoms can begin to appear shortly after birth and can include poor appetite, vomiting, irritability, and low energy. If left untreated, UCDs can cause coma and even death. Providers can check for UCDs through blood work. Treatments include medications that help lower ammonia levels in the blood.

Q: How is Ammonul (sodium phenylacetate / sodium benzoate) given?

Ammonul (sodium phenylacetate / sodium benzoate) is typically given in a healthcare setting by a provider. It should only be given through a tube inserted into a large vein in the neck, upper chest, or groin. This is known as a [central line](https://www.goodrx.com/health-topic/procedures/central-line). It's different from a peripheral line, which is usually inserted into a small vein in the hand or arm. Ammonul (sodium phenylacetate / sodium benzoate) should never be given through a peripheral line, because it can cause burns. The dose of Ammonul (sodium phenylacetate / sodium benzoate) that you receive is determined by your healthcare provider based on your weight or body size. You'll typically receive an initial dose that's given over one and a half to two hours. Then, you'll receive another dose that's given over a longer period of time (usually 24 hours). This dose is continued until your ammonia levels are back within normal range or when you're able to tolerate food and medications taken by mouth.

Q: Does Ammonul (sodium phenylacetate / sodium benzoate) have any serious side effects?

Yes, Ammonul (sodium phenylacetate / sodium benzoate) can cause damage to the brain, especially if taken for a long period of time or if doses need to be repeated often. This might result in tiredness, lightheadedness, headaches, confusion, hearing loss, and problems with memory. These side effects usually go away once you stop receiving the medication. Ammonul (sodium phenylacetate / sodium benzoate) might also cause too much sodium to build up in your blood. This can cause your body to hold onto water and lead to swelling, which might result in high blood pressure and worsening heart problems. People with heart or kidney problems are especially at risk for this side effect. Your provider will monitor your labs while you're receiving treatment with Ammonul (sodium phenylacetate / sodium benzoate) to make sure it's safe for you.

Generic Ammonul

Used for Urea Cycle Disorders

Ammonul (sodium phenylacetate / sodium benzoate) is a medication that's used as part of a treatment plan for people with urea cycle disorders (UCDs). It helps lower the amount of ammonia in the blood. This medication must be injected into a large vein, so it's typically only given in a hospital setting.

Reviewed by:

Sarah Lobello Pearson, PharmD

Kristianne Hannemann, PharmD

Last reviewed on May 31, 2022

What is Ammonul (sodium phenylacetate / sodium benzoate)?

What is Ammonul (sodium phenylacetate / sodium benzoate) used for?

High ammonia levels in the blood caused by certain types of urea cycle disorders (UCDs)

Are you looking for information on sodium phenylbutyrate (Buphenyl) instead?

Drug facts

Common Brands	Ammonul
Drug Class	Urea cycle disorder agent
Controlled Substance Classification	Not a controlled medication
Generic Status	No lower-cost generic available
Availability	Prescription only

Common Brands

Ammonul

Drug Class

Urea cycle disorder agent

Controlled Substance Classification

Not a controlled medication

Generic Status

No lower-cost generic available

Availability

Prescription only

Common questions about Sodium Phenylacetate/Sodium Benzoate

Sodium Phenylacetate/Sodium Benzoate is a medication that's used to treat children and adults with urea cycle disorders (UCDs) who have dangerously high ammonia levels in the blood. Normally, proteins in the liver turn ammonia into a waste product known as urea. The kidneys then get rid of urea by passing it in your urine. In people with UCDs, the proteins that turn ammonia into urea either don't work correctly or are missing. This means that excess ammonia builds up, and the body can't get rid of it. Too much ammonia in the blood is very toxic, especially to the brain. So, Sodium Phenylacetate/Sodium Benzoate helps the body break down ammonia to lower its levels in the blood.

Urea cycle disorders (UCDs) are rare, genetic conditions that are passed down from members of your family. UCDs affect about 1 in 35,000 births in the U.S. They happen when proteins that turn ammonia into a waste product called urea either don't work correctly or are missing. This leads to a toxic buildup of ammonia in the blood. Symptoms can begin to appear shortly after birth and can include poor appetite, vomiting, irritability, and low energy. If left untreated, UCDs can cause coma and even death. Providers can check for UCDs through blood work. Treatments include medications that help lower ammonia levels in the blood.

Sodium Phenylacetate/Sodium Benzoate is typically given in a healthcare setting by a provider. It should only be given through a tube inserted into a large vein in the neck, upper chest, or groin. This is known as a central line. It's different from a peripheral line, which is usually inserted into a small vein in the hand or arm. Sodium Phenylacetate/Sodium Benzoate should never be given through a peripheral line, because it can cause burns. The dose of Sodium Phenylacetate/Sodium Benzoate that you receive is determined by your healthcare provider based on your weight or body size. You'll typically receive an initial dose that's given over one and a half to two hours. Then, you'll receive another dose that's given over a longer period of time (usually 24 hours). This dose is continued until your ammonia levels are back within normal range or when you're able to tolerate food and medications taken by mouth.

The most common side effects of Sodium Phenylacetate/Sodium Benzoate are vomiting, high blood sugar, low potassium, involuntary muscle contractions, and problems with thinking.

Yes, Sodium Phenylacetate/Sodium Benzoate can cause damage to the brain, especially if taken for a long period of time or if doses need to be repeated often. This might result in tiredness, lightheadedness, headaches, confusion, hearing loss, and problems with memory. These side effects usually go away once you stop receiving the medication. Sodium Phenylacetate/Sodium Benzoate might also cause too much sodium to build up in your blood. This can cause your body to hold onto water and lead to swelling, which might result in high blood pressure and worsening heart problems. People with heart or kidney problems are especially at risk for this side effect. Your provider will monitor your labs while you're receiving treatment with Sodium Phenylacetate/Sodium Benzoate to make sure it's safe for you.

Ammonul (sodium phenylacetate / sodium benzoate) dosage

Typical dosage for Ammonul (sodium phenylacetate / sodium benzoate)

What are alternatives to Ammonul (sodium phenylacetate / sodium benzoate)?

There are a number of medications that your doctor can prescribe in place of Ammonul (sodium phenylacetate / sodium benzoate). Compare a few possible alternatives below.

Ammonul (sodium phenylacetate / sodium benzoate)

Used for: