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Generic Name: sodium phenylbutyrate (SOE dee um FEN il BUE ti rate)
Brand Name: Buphenyl

What is Buphenyl?

Buphenyl is converted to a substance in the body that helps the kidneys eliminate waste substances from the body. These waste substances can produce ammonia, which is toxic if it builds up in your blood.

Buphenyl is used to treat urea cycle disorders in people who lack certain liver enzymes needed to properly eliminate waste substances from the body. This medicine helps prevent a build-up of ammonia in the blood.

Buphenyl may also be used for other purposes not listed in this medication guide.

Important Information

Seek emergency medical attention if you notice any signs of ammonia build-up, including mood or behavior changes, memory loss, thinking problems, muscle twitching, back and forth movement of the eyes, vomiting, increasing weakness, slurred speech, seizure (convulsions), and fainting.

Buphenyl will not treat immediate symptoms of an ammonia build-up.

Before taking this medicine

You should not use Buphenyl if you are allergic to it. This medicine will not treat immediate symptoms of an ammonia build-up.

To make sure Buphenyl is safe for you, tell your doctor if you have:

FDA pregnancy category C. It is not known whether Buphenyl will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

It is not known whether Buphenyl passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give this medicine to a child who weighs less than 44 pounds unless your doctor tells you to.

How should I take Buphenyl?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Take this medicine with each meal. Divide your total daily dose among all of your meals for the day.

Buphenyl powder should be mixed with food before consuming.

Shake the powder lightly before mixing it with food.

Use Buphenyl regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely. You may need to take this medicine for the rest of your life.

Call your doctor right away if you have any signs of infection such as fever, chills, redness, swelling, body aches, or weakness. An infection may cause your condition to go out of control even while you are taking Buphenyl.

While using Buphenyl, you may need frequent blood tests.

Buphenyl is only part of a treatment program that may also include diet, dialysis, and other medications. Follow your doctor's instructions very closely.

Keep using this medicine even if you feel well. Your condition may have no symptoms. If the urea cycle disorder is not under control, you may have a build-up of ammonia, which can cause life-threatening side effects.

Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Be sure to take this medicine with food.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Buphenyl?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Buphenyl side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Even with treatment, urea cycle disorders can cause a build-up of ammonia in the blood which can result in life-threatening side effects. Seek emergency medical attention if you notice any signs of ammonia build-up, including mood or behavior changes, memory loss, thinking problems, muscle twitching, back and forth movement of the eyes, vomiting, increasing weakness, slurred speech, seizure (convulsions), and fainting.

Call your doctor at once if you have:

  • severe drowsiness, confusion;

  • swelling, rapid weight gain;

  • a light-headed feeling, like you might pass out; or

  • pale skin, feeling short of breath, rapid heart rate.

Common side effects may include:

  • missed menstrual periods, changes in your regular cycle;

  • loss of appetite;

  • headache; or

  • unusual or unpleasant taste in your mouth.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect Buphenyl?

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with Buphenyl, especially:

This list is not complete. Other drugs may interact with sodium phenylbutyrate, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

  • Your pharmacist can provide more information about Buphenyl.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 3.01.

Date modified: March 06, 2018
Last reviewed: July 16, 2014