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Other drug names: A-Am An-Az B C-Ch Ci-Cz D-Dh Di-Dz E F G H I-J K-L M-Mh Mi-Mz N-Nh Ni-Nz O P-Pl Pm-Pz Q-R S-Sn So-Sz T-To Tp-Tz U-V W-Z 0-9   

Sodium Phenylbutyrate (Systemic)

Brand Names

In the U.S.-

  • Buphenyl


  • Antihyperammonemic


Sodium phenylbutyrate (SOE-dee-um fen-il-BYOO-ti-rate) is used to help treat a deficiency of enzymes that help remove ammonia from your body.

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.

Sodium phenylbutyrate is available only with your doctor's prescription, in the following dosage forms:

  • Powder for solution (U.S.)
  • Tablets (U.S.)

Before Using This Medicine

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 sodium phenylbutyrate, the following should be considered:

Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to sodium phenylbutyrate. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy- Studies on effects in pregnancy have not been done in either humans or animals.

Breast-feeding- It is not known whether sodium phenylbutyrate passes into breast milk.

Children- This medicine has been reported to cause unwanted side effects in children. Also, nerve problems and brain damage associated with your condition may continue to worsen despite treatment.

Older adults- Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing the use of sodium phenylbutyrate in the elderly with use in other age groups.

Other 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 sodium phenylbutyrate, it is especially important that your health care professional know if you are taking the following:

  • Probenecid-Probenecid may increase the effects of sodium phenylbutyrate

Other medical problems- The presence of other medical problems may affect the use of sodium phenylbutyrate. Make sure you tell your doctor if you have any other medical problems, especially:
  • Edema (swelling) or
  • Heart disease or
  • Kidney disease, severe-Increased retention of water may make these conditions worse
  • Kidney disease or
  • Liver disease-Higher blood levels of sodium phenylbutyrate may result and increase the risk of side effects

Proper Use of This Medicine

For patients taking the powder form of this medicine:

  • Sodium phenylbutyrate should be mixed with solid food or a liquid. However, it should not be mixed with acidic beverages such as coffee, tea, or grapefruit, orange, or tomato juice.

Take this medicine with meals or feedings.

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 sodium phenylbutyrate 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 sodium phenylbutyrate. If your dose is different, do not change it unless your doctor tells you to do so.

  • For too much ammonia in the body:
    • For oral dosage form (powder for solution):
      • Adults, teenagers, and children weighing 20 kilograms (kg) (44 pounds) or more-The dose is based on body size and must be determined by your doctor. It is usually given four to six times a day with meals or feedings. The dose is usually not more than 20 grams a day.
      • Children weighing up to 20 kg (44 pounds)-The dose is based on body weight. The usual dose is 450 to 600 milligrams (mg) per kg (205 to 273 mg per pound) of body weight a day. The dose is given four to six times a day with meals or feedings. The dose is usually not more than 20 grams a day.
    • For oral dosage form (tablets):
      • Adults, teenagers, and children weighing 20 kg (44 pounds) or more-The dose is based on body size and must be determined by your doctor. It is usually given three times a day with meals or feedings. The dose is usually not more than 20 grams (40 tablets) a day.
      • Children weighing up to 20 kg (44 pounds)-Use of the tablets is not recommended.

Missed dose-

If you miss a dose of this medicine, take it as soon as possible. It is important to take the full amount every day as prescribed by your doctor.


To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down. However, a strong, musty odor is normal for your medicine.
  • Keep the medicine from freezing. Do not refrigerate.
  • Keep container tightly closed.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

Your doctor should check your progress at regular visits to make sure that this medicine is working properly.

Side Effects of This Medicine

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 as soon as possible if any of the following side effects occur :

  • More common
    • Change in frequency of breathing;  lack of or irregular menstruation;  mood or mental changes ;  muscle pain or twitching;  nausea or vomiting;  nervousness or restlessness;  lower back, side, or stomach pain;  swelling of feet or lower legs;  unpleasant taste ;  unusual tiredness or weakness 

  • Less common
    • Chills;  fever;  joint pain;  sore throat;  unusual bleeding or bruising 

  • Rare
    • Convulsions (seizures);  dizziness;  dryness of mouth;  fast, slow, or irregular heartbeat;  increased blood pressure;  increased thirst;  irritability;  muscle cramps;  rectal bleeding;  swelling of face;  unusual weight gain ;  weak pulse 

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

  • Less common
    • Changes in taste;  decreased appetite ;  strong body odor 

  • Rare
    • Abdominal or stomach pain;  constipation ;  fainting;  headache;  mental depression;  skin rash 

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

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT