Bylvay (odevixibat) is an oral capsule that may be used to treat itching (pruritus) caused by progressive familial intrahepatic cholestasis (PFIC; a genetic disorder) in adults and children 3 months of age and older. A limitation of use is that it may not be effective in PFIC2, a subtype of PFIC caused by mutations in the ABCB11 gene.

Bylvay may also be used to treat cholestatic pruritus in patients 12 months of age and older with Alagille syndrome (ALGS).

Although the exact way Bylvay works to reduce itching in patients with PFIC or Alagille syndrome is unknown, it is thought to be due to a reduction in serum bile acids. Bylvay is an ileal bile acid transporter (IBAT) inhibitor that decreases the reabsorption of bile acids (mainly the salt forms) from the terminal ileum (this is the end segment of the small intestine). This results in lower levels of bile acids in the blood.

Progressive familial intrahepatic cholestasis (PFIC) and cholestatic pruritus due to Alagille syndrome are conditions caused by genetic mutations that cause impaired bile flow. The subsequent toxic build-up of bile acids can lead to pruritus, which can be severe and debilitating.

There are no contraindications to the use of Bylvay.

May not be effective in PFIC type 2 patients with ABCB11variants resulting in non-functional or complete absence of bile salt export pump protein (BSEP-3).

May cause liver test abnormalities. Your doctor will conduct liver tests before and during treatment with Bylvay. Dose reduction or treatment interruption may be required if abnormalities occur and treatment discontinuation should be considered for persistent or recurrent abnormalities.

Diarrhea may occur. Treat dehydration and withhold or discontinue treatment for persistent diarrhea.

Can cause fat-soluble vitamin (FSV) deficiency. Doctors should obtain baseline levels of fat-soluble vitamins and monitor them during treatment. Doctors should supplement if a deficiency is observed, but if the deficiency persists or worsens, then they should discontinue treatment.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your child's dose. Use the medicine exactly as directed.

Bylvay capsules or pellets should be taken once a day with each morning meal (breakfast).

• Bylvay oral pellets come in a capsule that must be opened. Empty the pellets into a small amount of soft food such as applesauce, chocolate or rice pudding, oatmeal, or pureed bananas or carrots. Stir and give the mixture to your child right away, then give the child a glass of water. Throw away the empty capsule.
• For Bylvay capsules, your child should swallow the capsule whole. Do not crush, chew, or break the capsule. If your child cannot swallow a capsule whole, open the capsule and mix the medicine with soft food as directed above for the oral pellets.

Do not mix Bylvay pellets or capsules with liquids.

Your child will need frequent blood tests to check his or her liver function.

Call your doctor if your child's symptoms do not improve after 3 months.

Your doctor may recommend giving certain vitamin supplements to your child while using Bylvay. Use only the types and amounts of vitamins your doctor prescribes.

• Recommended dosage for PFIC for patients 3 months and older: 40 mcg/kg taken once a day.
• Recommended dosage for ALGS for patients 12 months and older: 120 mcg/kg once a day.

Doses are based on weight. Your child's dose may change if the child gains or loses weight.

You should not give Bylvay to a child who is on a liquid diet.

Tell your child's doctor if the child has ever had cirrhosis.

There is a pregnancy safety study that collects pregnancy outcome data in women taking Bylvay during pregnancy. Pregnant women exposed to Bylvay, or their healthcare providers, should report exposure by calling 1-855-252-4736.

Skip the missed dose and give your child the next dose at the regular time. Do not use two doses at one time.

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

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

Get emergency medical help if your child has signs of an allergic reaction: hives; difficulty breathing; swelling of the face, lips, tongue, or throat.

Call your doctor at once if your child has:

• severe or ongoing diarrhea, black or bloody stools
• rapid weight gain, stomach pain, and bloating
• vomiting large amounts of blood
• confusion, trouble concentrating, sleep problems, feeling anxious or irritable
• slurred speech, problems with balance or coordination
• uncontrolled muscle movement in the hands
• increased thirst, decreased urination or sweating
• a light-headed feeling
• changes in mood or behavior or
• new or worsening liver problems--loss of appetite, stomach pain (upper right side), tiredness, bruising or bleeding, increased itching, jaundice (yellowing of the skin or eyes).

Common side effects of Bylvay may include:

• stomach pain, diarrhea, vomiting
• abnormal liver function tests or
• deficiency in vitamins A, D, E, or K.

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 the FDA at 1-800-FDA-1088.

Give the Bylvay dose 4 hours before or 4 hours after giving any of the following:

• cholestyramine
• colesevelam or
• colestipol.

Other drugs may affect Bylvay, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.