Buphenyl

(Sodium Phenylbutyrate)

The active ingredient in Buphenyl is sodium phenylbutyrate.

Sodium phenylbutyrate is a prodrug. After you take it, the body converts it into phenylacetate, which then joins with the amino acid glutamine to form phenylacetylglutamine. In simple terms, Buphenyl helps the body get rid of waste nitrogen in another way, lowering ammonia levels when the urea cycle is not working properly. This is why it is used in the management of urea cycle disorders.

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide before using Buphenyl. However, the following is a synopsis of the general guidelines for the use of Buphenyl:

• Buphenyl is for oral use only. It is available as sodium phenylbutyrate tablets and Buphenyl Powder.
• The total daily dose is divided into equal portions and taken with each meal or feeding, usually 3 to 6 times per day.
• Buphenyl must be taken together with dietary protein restriction and, in some cases, essential amino acid or other supplementation, as directed by a metabolic or genetics specialist.
• If you miss a dose, take it as soon as you remember on the same day. If it is nearly time for the next dose, skip the missed dose. Do not take extra doses to make up for a missed dose.
• Buphenyl is not used to manage acute hyperammonemia. Any suspected episode of acute hyperammonemia is a medical emergency and requires immediate hospital treatment.

Some mild or common side effects of Buphenyl include:

• Decreased appetite.
• Body odor.
• Bad taste.
• Nausea.
• Vomiting.
• Abdominal pain.
• Constipation.
• Headache
• Lightheadedness.
• Sleepiness.
• Weight gain or swelling due to fluid retention.
• Amenorrhea or menstrual irregularities in premenopausal women.

Some individuals may experience serious side effects while using Buphenyl. These side effects may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

• Signs of heart problems or heart failure, such as rapid weight gain, swelling in the legs or feet, or shortness of breath.
• Symptoms of low potassium or acidosis, such as muscle weakness, irregular heartbeat, leg cramps, extreme tiredness, or rapid breathing.
• Unusual bleeding or bruising, anemia, or other blood changes noted on lab tests.
• Severe or persistent stomach pain, rectal bleeding, peptic ulcer symptoms, or pancreatitis.
• Rash or other signs of allergic reaction, including hives, swelling, or difficulty breathing.
• New or worsening mood changes, depression, or other neurologic symptoms.

These are not all of the possible side effects of Buphenyl. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting Buphenyl, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including if you have:

• A history of hyperammonemic encephalopathy or recent episodes of acute hyperammonemia. Any acute episode should be treated as a life-threatening emergency.
• Heart failure, high blood pressure, or conditions that cause sodium retention and swelling, because Buphenyl contains a significant amount of sodium and may worsen edema and heart problems.
• Renal insufficiency or decreased kidney function, because phenylacetylglutamine and other metabolites are excreted by the kidneys.
• Hepatic insufficiency or liver disease, since Buphenyl is metabolized in the liver.
• Inborn errors of beta oxidation or other metabolic conditions that might affect the handling of fatty-acid–like molecules.
• A history of acidosis or electrolyte problems, including low potassium or other metabolic imbalances.
• Anemia or other blood disorders, as laboratory changes may occur and need monitoring.
• Any neurologic or psychiatric conditions.
• Any planned or recent use of medicines such as valproic acid, haloperidol, corticosteroids, or probenecid (see drug interactions).
• Buphenyl therapy requires regular monitoring of plasma ammonia levels, plasma amino acids (including glutamine), and general blood tests to check for metabolic or hematologic side effects. It is usually prescribed and followed by a healthcare professional experienced in managing urea cycle disorders.

Buphenyl should not be used in the following situations:

• To manage acute hyperammonemia, which is a medical emergency and requires rapid hospital-based treatment.

-In patients with known hypersensitivity to sodium phenylbutyrate or any component of the formulation.

When Buphenyl is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions.

When Buphenyl is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

• Valproic acid (Depakene and similar products) has been reported to increase blood ammonia levels and may worsen urea cycle disorders.
• Haloperidol (Haldol) has also been associated with increases in plasma ammonia.
• Corticosteroids may increase the breakdown of body protein and raise plasma ammonia levels.
• Probenecid can affect how the kidneys excrete Buphenyl’s metabolites and may alter drug levels.

Buphenyl does not give an immediate “symptom relief” feeling like some other medicines. Instead, it is part of the long-term management of urea cycle disorders. Once treatment and dietary changes are in place, your healthcare team will monitor plasma ammonia and glutamine levels over time.

Store at room temperature and keep out of reach of children.

Buphenyl (sodium phenylbutyrate) has been developed and marketed by companies associated with Ucyclyd Pharma and Horizon Therapeutics in North America.

Yes. Sodium phenylbutyrate is available in generic forms, including sodium phenylbutyrate tablets and powder.

Buphenyl is usually part of the long-term management of urea cycle disorders and is often needed for life, unless a liver transplant is performed. You should not stop taking Buphenyl on your own.

Talk to your doctor if you are already pregnant or if you have any plans to become pregnant. They will know or recommend what is best for you.

Talk to your doctor if you are already breastfeeding or if you have any plans to breastfeed. They will know or recommend what is best for you.