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Orfadin: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Orfadin - General Information

Orfadin is a synthetic reversible inhibitor of 4-hydroxyphenylpyruvate dioxygenase. It is used in the treatment of hereditary tyrosinemia type 1. It is sold under the brand name Orfadin. [Wikipedia]

 

Pharmacology of Orfadin

Hereditary tyrosinemia type 1 occurs due to a deficiency in fumarylacetoacetase (FAH), the final enzyme in the tyrosine catabolic pathway. Orfadin inhibits catabolism of tyrosine by preventing the catabolic intermediates. In patients with HT-1, these catabolic intermediates are converted to the toxic metabolites succinylacetone and succinylacetoacetate, which are responsible for the observed liver and kidney toxicity. Succinylacetone can also inhibit the porphyrin synthesis pathway leading to the accumulation of 5-aminolevulinate, a neurotoxin responsible for the porphyric crises characteristic of HT-1.

 

Additional information about Orfadin

Orfadin Indication: Used as an adjunct to dietary restriction of tyrosine and phenylalanine in the treatment of hereditary tyrosinemia type 1. Mechanism Of Action: Orfadin is a competitive inhibitor of 4-hydroxyphenyl-pyruvate dioxygenase, an enzyme upstream of fumarylacetoacetate hydrolyase (FAH) in the tyrosine catabolic pathway. By inhibiting the normal catabolism of tyrosine in patients with hereditary tyrosinemia type 1 (HT-1), nitisinone prevents the accumulation of the catabolic intermediates maleylacetoacetate and fumarylacetoacetate. Drug Interactions: Not Available Food Interactions: Not Available Generic Name: Nitisinone Synonyms: Not Available Drug Category: Enzyme Inhibitors Drug Type: Small Molecule; Approved Other Brand Names containing Nitisinone: Orfadin; Absorption: The capsule and liquid formulations are bioequivalent in both the plasma concentration-time curve and maximum plasma concentration (Cmax). Toxicity (Overdose): Side effects include elevated plasma levels of this amino acid, hepatic and liver failure. Protein Binding: Not Available Biotransformation: Not Available Half Life: ~54 hours Dosage Forms of Orfadin: Capsule Oral Chemical IUPAC Name: 2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione Chemical Formula: C14H10F3NO5 Nitisinone on Wikipedia: https://en.wikipedia.org/wiki/Nitisinone Organisms Affected: Humans and other mammals