Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page:

Sodium Phenylbutyrate and Taurursodiol

pronounced as (soe' dee um fen" il bue' ti rate and taur ur" soe dye' ol )


Sodium phenylbutyrate and taurursodiol is no longer commercially available in the U.S. See the FDA website ( for information on drugs that have been discontinued.

Because this drug is no longer available in the U.S. market, this document is no longer updated by AHFS DI. If this drug is used in countries other than the U.S., it is essential that the manufacturers' labeling be consulted for more recently available information.

Why is this medication prescribed?

Sodium phenylbutyrate and taurursodiol is used for the treatment of amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease; a condition in which the nerves that control muscle movement slowly die, causing the muscles to shrink and weaken). Sodium phenylbutyrate is a histone deacetylase inhibitor. Taurursodiol is a bile acid. It is not known exactly how the combination of sodium phenylbutyrate and taurursodiol works, but it may reduce the breakdown and death of nerve cells associated with the worsening of ALS symptoms.

How should this medicine be used?

Sodium phenylbutyrate and taurursodiol comes as a powder to be mixed with water and taken by mouth or through a feeding tube. It is usually taken before a snack or a meal one time a day for 3 weeks then twice a day thereafter. Take sodium phenylbutyrate and taurursodiol at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take sodium phenylbutyrate and taurursodiol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Open 1 packet and place contents into a cup of 8 ounces of room temperature water and stir vigorously. All of the medication mixed in water must be administered within 1 hour if stored at room temperature. Any medication that remains after that, must be thrown out.

Sodium phenylbutyrate and taurursodiol controls ALS but does not cure it. Continue to take sodium phenylbutyrate and taurursodiol even if you feel well. Do not stop taking sodium phenylbutyrate and taurursodiol without talking to your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking sodium phenylbutyrate and taurursodiol,

  • tell your doctor and pharmacist if you are allergic to sodium phenylbutyrate or taurursodiol, any other medications, or any of the ingredients in sodium phenylbutyrate and taurursodiol powder. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while taking sodium phenylbutyrate and taurursodiol. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • if you are taking aluminum-based antacids such as Mylanta, Maalox, or AlaMag, talk to your doctor about using a different antacid as these medications can interfere with the absorption of sodium phenylbutyrate and taurursodiol.
  • tell your doctor if you have or have ever had pancreatic or gastrointestinal diseases, malabsorption (difficulty or trouble digesting food), gallbladder issues, surgery on your bowels or intestines, or liver disease.
  • tell your doctor if you have heart failure, high blood pressure, or kidney disease. Sodium phenylbutyrate and taurursodiol contains 928 mg of sodium and so people with these disease states may need to restrict sodium intake from their diet while receiving sodium phenylbutyrate and taurursodiol.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking sodium phenylbutyrate and taurursodiol, call your doctor.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Sodium phenylbutyrate may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • nausea
  • cough, fever, shortness of breath, runny nose, sneezing
  • fatigue
  • extra salivation or drooling
  • dizziness

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • diarrhea
  • abdominal pain

Sodium phenylbutyrate and taurursodiol may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Store packets out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( for more information if you do not have access to a take-back program.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What other information should I know?

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Relyvrio®
Last Revised - 06/20/2024