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Buphenyl (Oral)

Generic name: sodium phenylbutyrateSOE-dee-um-fen-il-BUE-ti-rate ]
Brand names: Buphenyl, Olpruva, Pheburane, SPB11
Drug class: Urea cycle disorder agents

Medically reviewed by Last updated on Nov 11, 2023.

Uses for Buphenyl

Sodium phenylbutyrate is used together with a proper diet to help treat urea cycle disorders, including carbamylphosphate synthetase deficiency (CPS), ornithine transcarbamylase deficiency (OTC), or argininosuccinate synthetase (AS).

Ammonia is formed from the breakdown of protein in the body. If the ammonia cannot be removed by the body, then a buildup may cause serious unwanted effects. This medicine works by helping to reduce high levels of ammonia in the blood.

This medicine is available only with your doctor's prescription.

Before using Buphenyl

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of Olpruva™ in children weighing 20 kilograms (kg) or more and with a body surface area (BSA) of 1.2 square meter (m). Safety and efficacy have been established. Use is not recommended to treat acute hyperammonemia in children, in children weighing less than 20 kg, and in children weighing 20 kg or more with a BSA of less than 1.2 m.

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of Pheburane® in children. Safety and efficacy have been established. Use is not recommended to treat acute hyperammonemia in children.

Because of Buphenyl® s toxicity, use in children weighing less than 20 kilograms (44 pounds) is not recommended.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of Pheburane® and Olpruva™ in the elderly. However, elderly patients are more likely to have age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving this medicine.

No information is available on the relationship of age to the effects of Buphenyl® in geriatric patients.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of Buphenyl

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects. Also, do not stop using this medicine without checking first with your doctor.

This medicine comes with a patient information leaflet. Read and follow the instructions in the insert carefully. Ask your doctor if you have any questions.

For patients taking the powder form of this medicine:

Take this medicine with food.

To use the Olpruva™ oral liquid:

To use the Pheburane® oral pellets:

It is important that you follow any special instructions from your doctor, such as following a low-protein diet. Also, your doctor may recommend that you take amino acid supplements. If you have any questions about this, check with your doctor.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Pheburane® oral pellets: If you have less than 3 hours before your next scheduled dose, skip the missed dose and go back to your regular dosing schedule.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Throw away unused Pheburane® oral pellets 45 days after opening the bottle.

Precautions while using Buphenyl

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

This medicine may cause nervous system problems. Check with your doctor right away if you have confusion, headache, lightheadedness, nausea, sleepiness, tiredness, or vomiting.

In case of emergency—There may be a time when you need emergency help for a problem caused by your urea cycle disorders. You need to be prepared for these emergencies. It is a good idea to wear a Medic Alert tag at all times. Also, carry an ID card in your wallet or purse that says you have this disease and a list of all of your medicines.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of Buphenyl

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Less common


Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Incidence not known

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Endocrine-Metabolic Agent

Pharmacologic Class: Histone Deacetylase Inhibitor

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.