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Nitisinone Brand Names- NITYR | Orfadin

What is Nitisinone

Nitisinone inhibits the breakdown of tyrosine in patients with hereditary tyrosinemia type I (HT-1).

Patients with HT-1 are deficient in fumarylacetoacetate hydrolase (FAH), the final enzyme in the tyrosine catabolism pathway.

Fewer than 100 children in the US are affected by this condition. Nitisinone was originally developed as a weed killer, but was unsuccessful. Swedish scientists then discovered its use in the treatment of HT-1.

Prior to the introduction of nitisinone, the only treatments for HT-1 were dietary restriction of tyrosine and phenylalanine and liver transplantation.

The 2- and 4-year survival probabilities for patients presenting with HT-1 under 2 months of age and treated with dietary restriction and nitisinone are 88% and 88%, respectively, as compared to historical controls treated with dietary restriction alone, 29% and 29%, respectively.

The clinical trial of nitisinone also suggests a decreased incidence of porphyric crisis in these patients.

Because nitisinone inhibits the breakdown of tyrosine, treatment with nitisinone requires restriction of dietary intake of tyrosine and phenylalanine to prevent toxicity.

During dosage titration, monitor plasma and/or urine succinylacetone concentrations, liver function parameters, and alpha-fetoprotein levels. Due to the potential for thrombocytopenia or leukopenia, monitor platelet and white blood cell counts during therapy.


  • hereditary tyrosinemia type I

For the treatment of hereditary tyrosinemia type I

NOTE: Nitisinone has been designated an orphan drug by the FDA for this indication.

Side Effects

  1. abdominal pain
  2. alopecia
  3. blepharitis
  4. cataracts
  5. conjunctivitis
  6. corneal opacification
  7. diarrhea
  8. epistaxis
  9. exfoliative dermatitis
  10. headache
  11. hepatic failure
  12. keratitis
  13. leukopenia
  14. maculopapular rash
  15. ocular pain
  16. photophobia
  17. porphyria
  18. pruritus
  19. thrombocytopenia
  20. xerosis

Monitoring Parameters

  • LFTs
  • serum alpha-fetoprotein
  • serum phenylalanine (Phe) concentrations
  • serum tyrosine
  • urinary succinylacetone


  • breast-feeding
  • hepatic disease
  • leukopenia
  • neoplastic disease
  • ocular disease
  • porphyria
  • pregnancy
  • thrombocytopenia
  • tyrosinemia


  • Adefovir
  • Amlodipine; Celecoxib
  • Aspirin, ASA; Pravastatin
  • Bictegravir; Emtricitabine; Tenofovir Alafenamide
  • Celecoxib
  • Cidofovir
  • Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide
  • Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide
  • Emtricitabine; Rilpivirine; Tenofovir alafenamide
  • Emtricitabine; Tenofovir alafenamide
  • food
  • Fosphenytoin
  • Furosemide
  • Ganciclovir
  • Glimepiride
  • Glimepiride; Pioglitazone
  • Glimepiride; Rosiglitazone
  • Methadone
  • Methotrexate
  • Penicillin G
  • Penicillin G Benzathine
  • Penicillin G Benzathine; Penicillin G Procaine
  • Penicillin G Procaine
  • Phenytoin
  • Pravastatin
  • Tenofovir Alafenamide
  • Tenofovir Alafenamide
  • Tolbutamide
  • Warfarin

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