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

About 1 in every 100,000 babies born will have tyrosinemia.

Tyrosinemia is an extremely rare but treatable hereditary disorder that must be inherited from both parents. Boys and girls are affected in equal numbers. When a child has tyrosinemia, their bodies lack the enzymes needed to break down tyrosine.

Tyrosine comes from food. It is one of the 20 amino acids, the building blocks of protein. When the body cannot break down tyrosine, high levels build up in the blood and form a toxic substance (knows as succinylacetone) in the liver, kidneys, and central nervous system. This means that if tyrosinemia isn't treated, it may cause liver and kidney damage and brain-related problems, such as problems with learning.

The most severe form of the disorder is type 1.

There are three types of tyrosinemia. The type a child has depends on which enzyme they are lacking. Children with tyrosinemia type 1 (HT-1) are deficient in an enzyme called fumarylacetoacetate hydrolase. If not recognized and treated right away, the condition could be fatal for a child at an early age. However, with treatment, tyrosine levels in the blood can be managed.

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.
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