Prescribing Information | Important Safety Information
Prescribing Information | Important Safety Information

The Network of Tyrosinemia Advocates

A resource for news and events in the community.

Learn More

National Organization for Rare Disorders

A patient advocacy organization dedicated to individuals with rare diseases.

Learn More

What is Tyrosinemia Type 1?

Tyrosinemia type 1 (HT-1) is a very rare hereditary disorder. People with HT-1 lack the proper enzymes needed to break down tyrosine, an amino acid. This deficiency leads to a toxic buildup of tyrosine in the body which can damage tissue and organs.

Learn More

How is HT-1 Treated?

Two important factors are diet and medication.

Read More

Get Help & Support

Discover resources for managing HT-1.

Read More

Stay Informed

Want to be alerted when new information is available? Sign up now.

I agree to receive communications from Sobi, Inc. about Orfadin (nitisinone) and related programs.

Indication and Usage

Orfadin is a synthetic reversible inhibitor of 4-hydroxyphenylpyruvate dioxygenase indicated for use as an adjunct to dietary restriction of tyrosine and phenylalanine in the treatment of hereditary tyrosinemia type 1 (HT-1).

Important Safety Information

    • Tyrosine levels can increase in the blood if you do not restrict tyrosine and phenylalanine in your diet while taking Orfadin. Too much tyrosine in the blood can cause serious eye problems or other complications.
    • Do not adjust your Orfadin dosage in order to lower the tyrosine levels in the blood.
    • A reduction in the number of white cells and platelets in the blood have been observed during treatment with Orfadin. Your platelet and white blood cell counts should be monitored regularly during Orfadin treatment.
    • The most common adverse reactions to taking Orfadin are liver cancer, liver failure, low platelets or white cells in the blood, and complaints related to the eyes, including conjunctivitis, corneal opacity, inflammation of the cornea, and extreme sensitivity to light.
    • Tell your physician promptly if you have unexplained eye symptoms, rash, jaundice (yellowing of the skin or whites of the eyes) or excessive bleeding.
    • Use Orfadin during pregnancy only if the potential benefit justifies the potential risk to the fetus.
    • Nursing women should discontinue either Orfadin or breast-feeding based on the recommendation of your healthcare professional.
      Please see full Prescribing Information