Molecule
Nitisinone is a 4-hydroxyphenyl-pyruvate dioxygenase inhibitor indicated for the treatment of adult and pediatric patients with hereditary tyrosinemia type 1 (HT-1) in combination with dietary restriction of tyrosine and phenylalanine. MedsAcross supplies Nitisinone for export from India to licensed hospitals, importers and physicians acting for named patients, with the documents each country requires.
Information from the US FDA prescribing information, retrieved 12 November 2026. Not yet medically reviewed.How we review
From the regulator-approved product information. Each section names its source.
ORFADIN ® is indicated for the treatment of adult and pediatric patients with hereditary tyrosinemia type 1 (HT-1) in combination with dietary restriction of tyrosine and phenylalanine. ORFADIN is a hydroxy-phenylpyruvate dioxygenase inhibitor indicated for the treatment of adult and pediatric patients with hereditary tyrosinemia type 1 (HT-1) in combination with dietary restriction of tyrosine and phenylalanine.
Source: US FDA prescribing information
Nitisinone is a competitive inhibitor of 4-hydroxyphenyl-pyruvate dioxygenase, an enzyme upstream of fumarylacetoacetate hydrolase (FAH) in the tyrosine catabolic pathway. By inhibiting the normal catabolism of tyrosine in patients with HT-1, nitisinone prevents the accumulation of the catabolic intermediates maleylacetoacetate and fumarylacetoacetate. 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.
Source: US FDA prescribing information
Recommended Dosage: The recommended starting dosage is 0.5 mg/kg orally twice daily. In patients 5 years of age and older who have undetectable serum and urine succinylacetone concentrations after a minimum of 4 weeks on a stable dosage of nitisinone, the total daily dose may be given once daily. Titrate the dosage based on biochemical and/or clinical response, as described in the full prescribing information. The maximum total daily dosage is 2 mg/kg orally. Preparation and Administration Instructions: For instructions on preparing, measuring and administering the oral suspension, see the full prescribing information.
Source: US FDA prescribing information
None. None
Source: US FDA prescribing information
Elevated Plasma Tyrosine Levels, Ocular Symptoms, Developmental Delay and Hyperkeratotic Plaques: Inadequate restriction of tyrosine and phenylalanine intake can lead to elevations in plasma tyrosine, which at levels above 500 micromol/L can result in symptoms, intellectual disability and developmental delay or painful hyperkeratotic plaques on the soles and palms, do not adjust ORFADIN dosage in order to lower the plasma tyrosine concentration. Obtain slit-lamp examination prior to treatment, regularly during treatment, Reexamine patients if symptoms develop or tyrosine levels are > 500 micromol/L. Assess plasma tyrosine levels in patients with an abrupt change in neurologic status. Leukopenia and Severe Thrombocytopenia: Monitor platelet and white blood cell counts.
Source: US FDA prescribing information
Most common adverse reactions (>1%) are elevated tyrosine levels, thrombocytopenia, leukopenia, conjunctivitis, corneal opacity, keratitis, photophobia, eye pain, blepharitis, cataracts, granulocytopenia, epistaxis, pruritus, exfoliative dermatitis, dry skin, maculopapular rash and alopecia.
Source: US FDA prescribing information
Nitisinone is a moderate CYP2C9 inhibitor, a weak CYP2E1 inducer and an inhibitor of OAT1/OAT3. Table 2 includes drugs with clinically important drug interactions when administered concomitantly with ORFADIN and instructions for preventing or managing them. Table 2: Clinically Relevant Interactions Affecting Co-Administered Drugs Sensitive CYP2C9 Substrates (e.g., celecoxib, tolbutamide) or CYP2C9 Substrates with a Narrow Therapeutic Index (e.g., phenytoin, warfarin) Clinical Impact Increased exposure of the co-administered drugs metabolized by CYP2C9. Intervention Reduce the dosage of the co-administered drugs metabolized by CYP2C9 drug by half. Additional dosage adjustments may be needed to maintain therapeutic drug concentrations for narrow therapeutic index drugs. See prescribing information for those drugs.
Source: US FDA prescribing information
Store refrigerated at 2° to 8°C (36° to 46°F). Alternatively, patients/caregivers may store ORFADIN capsules at room temperature up to 25°C (77°F) for up to 45 days. Oral suspension 4 mg/mL, NDC 66658-204-90 Store refrigerated at 2°C to 8°C (36°F to 46°F) prior to first use. Do not freeze. Store upright. After first opening, store the product at room temperature (up to 25°C (77°F)) for up to 60 days.
Source: US FDA prescribing information
For healthcare professionals and buyers. This is not medical advice. Treatment decisions belong to the prescriber.
13 presentations of Nitisinone, sorted by availability.
| Medicine | Manufacturer | Register | Availability |
|---|---|---|---|
| Nitisinone 10 mg capsuleOral Cold chainGeneric name | — | US FDA | Available on request |
| Nitisinone 2 mg capsuleOralGeneric name | — | US FDA | Available on request |
| Nitisinone 5 mg capsuleOralGeneric name | — | US FDA | Available on request |
| Nitisinone 20 mg capsuleOralGeneric name | — | US FDA | Available on request |
| Harliku 2 mg tabletOral | Cycle Pharmaceuticals | US FDA | Available on request |
| Nityr 10 mg tabletOral | Cycle Pharmaceuticals | US FDA | Available on request |
| Nityr 2 mg tabletOral | Cycle Pharmaceuticals | US FDA | Available on request |
| Nityr 5 mg tabletOral | Cycle Pharmaceuticals | US FDA | Available on request |
| Orfadin 10 mg capsuleOral Cold chain | Swedish Orphan Biovitrum AB (publ) | US FDA | Available on request |
| Orfadin 2 mg capsuleOral Cold chain | Swedish Orphan Biovitrum AB (publ) | US FDA | Available on request |
| Orfadin 20 mg capsuleOral Cold chain | Swedish Orphan Biovitrum AB (publ) | US FDA | Available on request |
| Orfadin 4 mg/mL oral suspensionOral Cold chain | Swedish Orphan Biovitrum AB (publ) | US FDA | Available on request |
| Orfadin 5 mg capsuleOral Cold chain | Swedish Orphan Biovitrum AB (publ) | US FDA | Available on request |
3 brand names across 1 markets.
Approval facts from US FDA, EMA and CDSCO data, and registration status by country where we hold register data.
Conditions linked to Nitisinone in public data. This is not a list of approved uses, see the clinical information.
Yes, on request. MedsAcross lists 13 presentations of Nitisinone and sources them for licensed hospitals, importers and physicians against valid import documents.
The catalogue lists 3 brand names for Nitisinone, including Harliku, Nityr, Orfadin.
Yes. The US FDA first approved Nitisinone on 18 January 2002, according to Drugs@FDA.
Yes. Nitisinone has a central EU marketing authorisation (status: authorised), according to European Medicines Agency data.
At least one listed presentation of Nitisinone must be kept cold, so it is shipped in temperature-controlled packaging. Check the storage line on each presentation.
Nitisinone is classified under ATC code A16AX04 (Nitisinone).
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