BUPHENYL® (sodium phenylbutyrate) Tablets and Powder


Approved Uses for BUPHENYL®
BUPHENYL (sodium phenylbutyrate) Tablets is a prescription medicine that can be taken by mouth and BUPHENYL (sodium phenylbutyrate) Powder is a prescription medicine that can be taken by mouth or feeding tube for the long-term management of high blood levels of ammonia (hyperammonemia) caused by a condition called a urea cycle disorder (UCD). BUPHENYL should be used if the UCD cannot be managed with a low-protein diet and dietary supplements alone.

BUPHENYL only treats high blood levels of ammonia in patients with the following enzyme deficiencies:

  • Carbamylphosphate synthetase (CPS)
  • Ornithine transcarbamylase (OTC)
  • Argininosuccinic acid synthetase (ASS)

BUPHENYL can be used in infants up to 28 days old who have a complete enzyme deficiency (an enzyme in the urea cycle that does not work at all). It can also be used in people 1 month of age and up who have a partial enzyme deficiency (an enzyme in the urea cycle that only works partially) and have a history of brain damage from high blood levels of ammonia (hyperammonemia). It is important to have a healthcare provider diagnose this condition and prescribe a medication as early as possible to improve chance of survival.

BUPHENYL must be used along with a low-protein diet and, in some cases, dietary supplements.
Any episode related to acute hyperammonemia should be treated as a life-threatening emergency.

Important Safety Information (ISI)
Do not take BUPHENYL if you are allergic to phenylbutyrate, or for the treatment of acute hyperammonemia in people with UCDs.

Use of BUPHENYL may cause serious side effects to the nervous system due to phenylacetate, a breakdown product of BUPHENYL. Call your doctor or get medical help right away if you experience any of the following symptoms while taking BUPHENYL: sleepiness, weakness, lightheadedness, problems with memory, worsening neuropathy (numbness, tingling, or burning in your hands or feet), change in taste, problems with hearing, confusion, and headache.

Talk to your doctor before taking BUPHENYL if you have heart failure or decreased kidney function, which may lead to retention of the sodium content of BUPHENYL with potentially serious consequences such as worsening heart failure, high blood pressure, and swelling. You and your doctor should decide if you will take BUPHENYL if you have these medical conditions. Do not take BUPHENYL if you have liver or kidney problems, have any other medical conditions, if your child is 20kg or less, or if you are planning to become pregnant or breastfeed, as it is unknown if BUPHENYL will harm your unborn baby or will pass into your breastmilk.

The most common side effects of BUPHENYL include absent or irregular periods in women, decreased appetite, body odor, and bad taste.

The most common side effects of BUPHENYL® seen in a laboratory setting include changes to blood pH and electrolyte levels (such as chloride and phosphate), low protein levels in the blood, high levels of certain bone and liver enzymes (such as alkaline phosphatase and transaminases), and decreased red and white blood cell and platelet count.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit http://www.fda.gov/medwatch, or call 1-800-FDA-1088.

This information is not intended to replace discussions with your doctor. For additional information about BUPHENYL®, please consult the Full Prescribing Information and the Information for the Patient/Caregiver and talk to your doctor. BUPHENYL® is available by prescription only.

Please see the Prescribing Information, including Patient Package Insert, for more information.