Nitisinone 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]
Indication
Used as an adjunct to dietary restriction of tyrosine and phenylalanine in the treatment of hereditary tyrosinemia type 1.
Pharmacology
Hereditary tyrosinemia type 1 occurs due to a deficiency in fumarylacetoacetase (FAH), the final enzyme in the tyrosine catabolic pathway. Nitisinone 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.
Toxicity
Side effects include elevated plasma levels of this amino acid, hepatic and liver failure.
Affected Organisms
Humans and other mammals
Absorption
The capsule and liquid formulations are bioequivalent in both the plasma concentration-time curve and maximum plasma concentration (Cmax).
Nitisinone is a herbicidal triketone that inhibits 4-hydroxyphenylpyruvate dioxygenase (HPPD), an enzyme involved in plastoquinone biosynthesis in plants and in tyrosine catabolism in mammals. It is used in treatment of inherited tyrosinemia type I.
References
PubChem Literature
From Data Sources
• Lindstedt, S., et al.: Lancet, 340, 813 (1992)
• Lock, E.A., et al.: J. Inherited Metab. Dis., 21, 498 (1992)
