Sodium Phenylbutyrate-Taurursodiol

Sodium Phenylbutyrate-Taurursodiol is a prescription medication used for the treatment of amyotrophic lateral sclerosis.

• Sodium Phenylbutyrate-Taurursodiol is available under the following different brand names: Relyvrio

Common side effects of Sodium Phenylbutyrate-Taurursodiol include:

• diarrhea
• abdominal pain
• nausea
• upper respiratory tract infection

Serious side effects of Sodium Phenylbutyrate-Taurursodiol include:

• worsening diarrhea

Rare side effects of Sodium Phenylbutyrate-Taurursodiol include:

• none 

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Powder for oral suspension

• (3 g/1 g)/single-dose packet

Amyotrophic Lateral Sclerosis

Adult dosage

• Initial: 1 packet (3 g sodium phenylbutyrate/ 1 g taurursodiol) orally every day for the first 3 weeks
• Maintenance: 1 packet orally twice a day

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Sodium Phenylbutyrate-Taurursodiol has severe interactions with no other drugs.
• Sodium Phenylbutyrate-Taurursodiol has serious interactions with no other drugs.
• Sodium Phenylbutyrate-Taurursodiol has moderate interactions with no other drugs.
• Sodium Phenylbutyrate-Taurursodiol has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• None

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Sodium Phenylbutyrate-Taurursodiol?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Sodium Phenylbutyrate-Taurursodiol?”

Cautions

• Each initial daily dosage of 1 packet contains 464 mg of sodium; each maintenance dosage of 2 packets daily contains 928 mg of sodium; consider the daily sodium intake in patients sensitive to salt intake (eg, those with heart failure, hypertension, or renal impairment) and monitor appropriately
• Risk with enterohepatic circulation disorders, pancreatic disorders, or intestinal disorders
• Taurursodiol is a bile acid
• May increase the risk of worsening diarrhea in patients with disorders that interfere with bile acid circulation; monitor appropriately
• Pancreatic insufficiency, intestinal malabsorption, or intestinal diseases may alter bile acid concentration and may lead to decreased absorption of Sodium Phenylbutyrate-Taurursodiol
• Owing to different enterohepatic circulation, pancreatic and intestinal disorders have varying degrees of severity; consider consulting with a specialist
• Enterohepatic circulation disorders (eg, biliary infection, active cholecystitis), severe pancreatic disorders (eg, pancreatitis), and intestinal disorders that may alter bile acid concentrations (eg, ileal resection, regional ileitis) were not studied; inform patients with such conditions about risks and benefits with use and advise to notify their healthcare provider if new or worsening diarrhea occurs
• Drug interaction overview
  • In-vitro studies show Sodium Phenylbutyrate-Taurursodiol
  • Induces CYP1A2, CYP2B6, and CYP3A4 at clinically relevant concentrations
  • Inhibits CYP2C8 and CYP2B6 at clinically relevant concentrations
  • Inhibits OAT1, P-gP, and BCRP at clinically relevant concentrations
  • Substrate of OATP1B3, MATE2-K, OAT3, and BSEP
  • Bile acid sequestering agents
    • Avoid use; consider alternative cholesterol-lowering agents
    • Bile acid sequestering agents (eg, cholestyramine, colestipol, colesevelam) may interfere with taurursodiol absorption
    • Bile acid transport inhibitors
    • Avoid the use of strong bile salt export pump (BSEP) inhibitors (eg, cyclosporine)
    • If coadministration is necessary, exercise caution and monitor serum ALT/AST and bilirubin
    • Medications that inhibit canalicular membrane bile acid transporters such as BSEP may exacerbate the accumulation of conjugated bile salts in the liver and result in clinical symptoms
  • Aluminum-based antacids
    • Avoid use and consider alternants
    • Aluminum-based antacids have been shown to adsorb bile acids in vitro and may interfere with taurursodiol absorption
  • Probenecid
    • Avoid use
    • Probenecid may affect the renal excretion of sodium phenylbutyrate metabolites
  • Pan-histone deacetylase (HDAC) inhibitors
    • Avoid coadministration with other HDAC inhibitors
  • OATP1B3 inhibitors
    • Avoid use
    • OATP1B3 inhibitors may increase Sodium Phenylbutyrate-Taurursodiol
  • Sensitive OAT1 substrates
    • Avoid coadministration with sensitive OAT1 substrates
    • Sodium Phenylbutyrate-Taurursodiol may increase plasma concentrations of OAT1 substrates
  • Sensitive P-glycoprotein (P-gP) and Breast Cancer Resistance Protein (BCRP) substrates
    • Avoid coadministration with sensitive P-gP and BCRP substrates
    • Sodium Phenylbutyrate-Taurursodiol may increase plasma concentrations of P-gP and BCRP substrates
  • CYP2C8, CYP1A2, CYP2B6, and CYP3A4 substrates
    • Avoid coadministration of sensitive substrates of CYP2C8, CYP1A2, CYP2B6, and CYP3A4
    • Sodium Phenylbutyrate-Taurursodiol may change plasma concentrations of substrates for these enzymes

Pregnancy and Lactation

• No data are available for use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes
• Lactation
  • There are no data on the presence of sodium phenylbutyrate or taurursodiol in human milk, its effects on breastfed infants, or milk production