Nitisinone: uses, dosing, side effects & brands
Nitisinone is a 4-hydroxyphenyl-pyruvate dioxygenase inhibitor sold in the U.S. under 3 brand and generic names, for tyrosinemias. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- 4-Hydroxyphenyl-Pyruvate Dioxygenase Inhibitor
- Treats (across its forms)
- Tyrosinemias
- Available as
- Tablet · Capsule · Suspension
- Sold as
- 3 products — Harliku, Nityr and Orfadin
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Half-life
- about 54 hours (mean terminal half-life)
How Harliku is dosed
From the FDA label for Harliku (application NDA209449). Other nitisinone products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended starting dosage is 0.5 mg/kg (actual body weight) administered orally twice daily. ( 2.1 ) Administer NITYR with or without food. ( 2.1 ) Maintain dietary restriction of tyrosine and phenylalanine when administering NITYR. ( 2.1 ) The recommended maintenance dosage of NITYR 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, is 1 to 2 mg/kg once daily. ( 2.1 ) See the full prescribing information for dosage titration and monitoring. ( 2.2 ) See the full prescribing information for preparation and administration instructions. ( 2.2 ) 2.1 Recommended Dosage The recommended starting dosage of NITYR is 0.5 mg/kg (actual body weight) administered orally twice daily. Titrate the dose in each individual patient based on biochemical and/or clinical response. Administer NITYR with or without food [see Clinical Pharmacology ( 12.3 )] . Maintain dietary restriction of tyrosine and phenylalanine when administering NITYR. Maintenance Dosage The recommended maintenance dosage of NITYR 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, is 1 to 2 mg/kg once daily [see Clinical Pharmacology ( 12.2 )] . A maximum total daily dosage of 2 mg/kg may be…
Everything below is the FDA label for Harliku (tablet). Nitisinone is also sold as capsule and suspension, and those are different medicines to take — follow the label for the one you were prescribed.
Harliku side effects
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. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Cycle Pharmaceuticals Ltd. at 1-855-831-5413 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Serious and or clinically significant adverse reactions described elsewhere in labeling include: Ocular Symptoms, Developmental Delay and Hyperkeratotic Plaques Due To Elevated Plasma Tyrosine Levels [see Warnings and Precautions ( 5.1 )] Leukopenia and Severe Thrombocytopenia [see Warnings and Precautions ( 5.2 )] 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of NITYR has been established based on studies of another oral formulation of nitisinone in patients with HT-1 [see Clinical Studies ( 14 )] . Below is a display of the adverse reactions of nitisinone in these studies. Nitisinone was studied in one open-label, uncontrolled study of 207 patients with HT-1, ages 0 to 22 years at…
Who shouldn’t take Harliku
None. None. ( 4 )
Harliku drug interactions
CYP2C9 Substrates : Increased systemic exposure of these co-administered drugs; reduce the dosage. Additional dosage adjustments may be needed to maintain therapeutic drug concentrations for narrow therapeutic index drugs. ( 7 ) OAT1/OAT3 Substrates : Increased systemic exposure of these co-administered drugs; monitor for potential adverse reactions. ( 7 ) Nitisinone is a moderate CYP2C9 inhibitor, a weak CYP2E1 inducer and an inhibitor of OAT1/OAT3. TABLE 2 includes drugs with clinically significant drug interactions when administered concomitantly with NITYR and instructions for preventing or managing them. TABLE 2. Clinically Significant 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. [see Clinical Pharmacology ( 12.3 )] Prevention or Management 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. OAT1/OAT3 Substrates (e.g., adefovir, ganciclovir, methotrexate) Clinical Impact Increased exposure of the interacting drug. [see Clinical Pharmacology ( 12.3 )] Prevention or Management Monitor for potential adverse reactions related to the co-administered drug.
Every nitisinone product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 2 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 3 | Not yet rated | Prescription | Capsule | No data | — | View → |
What nitisinone pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
Can you crush or split nitisinone?
The nitisinone labels that address it permit crushing or splitting in the terms they state — quoted per product, because the instruction belongs to the form.
What each nitisinone label says about crushing, splitting and chewingHow long nitisinone keeps
The date on a sealed pack is not the only one: some nitisinone labels start a second clock once the product is opened or mixed, as short as 2 hours.
Does nitisinone expire? The in-use limits and storage rules from its labelsWhat people report to the FDA about nitisinone
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 189 reports naming nitisinone, and the FDA flagged 90% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- liver transplant44 reports
- hepatocellular carcinoma24 reports
- amino acid level increased21 reports
- hepatic failure16 reports
- hepatic cirrhosis14 reports
- alpha 1 foetoprotein increased11 reports
- vitiligo9 reports
- keratitis6 reports
Read these as a signal, not a rate. A report does not mean nitisinone caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
How long nitisinone stays in your system
The elimination half-life of nitisinone is about 54 hours (mean terminal half-life). This is the terminal (elimination) half-life the ORFADIN label reports for a single dose in healthy male adults — roughly 2 days, which is why once-daily dosing works and why it takes about 2 weeks (steady state within 14 days) for levels to plateau after a change. The label does not describe an active metabolite, and nitisinone is not a prodrug: it is only minimally metabolized (in vitro, minor metabolism possibly via CYP3A4) and renal excretion is minor (about 3% of the dose unchanged in urine). The figure is formulation-specific: the NITYR tablet label reports a mean terminal half-life of 59.3 hours (SD 8.9) in healthy subjects. Populations: the label provides NO pharmacokinetic data in kidney impairment or liver impairment, and states that clinical studies included no subjects 65 or over and that no PK studies were done in geriatric patients (it only advises cautious dose selection in the elderly) — so how the half-life shifts in those groups is not established on the label.
ORFADIN (nitisinone) capsules/oral suspension — FDA label via DailyMed, §12.3 Pharmacokinetics (Elimination) ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Related calculators
Frequently asked questions
What is Harliku?
NITYR (nitisinone) is a hydroxyphenyl-pyruvate dioxygenase inhibitor. Nitisinone occurs as a white to yellowish-white, crystalline powder. It is practically insoluble in water, soluble in 2M sodium hydroxide and in methanol, and sparingly soluble in alcohol.
What kind of drug is nitisinone?
The FDA classifies nitisinone as a 4-hydroxyphenyl-pyruvate dioxygenase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
How long does nitisinone stay in your system?
The elimination half-life of nitisinone is about 54 hours (mean terminal half-life) — that is how long the body takes to clear half of a dose. This is the terminal (elimination) half-life the ORFADIN label reports for a single dose in healthy male adults — roughly 2 days, which is why once-daily dosing works and why it takes about 2 weeks (steady state within 14 days) for levels to plateau after a change. The label does not describe an active metabolite, and nitisinone is not a prodrug: it is only minimally metabolized (in vitro, minor metabolism possibly via CYP3A4) and renal excretion is minor (about 3% of the dose unchanged in urine). The figure is formulation-specific: the NITYR tablet label reports a mean terminal half-life of 59.3 hours (SD 8.9) in healthy subjects. Populations: the label provides NO pharmacokinetic data in kidney impairment or liver impairment, and states that clinical studies included no subjects 65 or over and that no PK studies were done in geriatric patients (it only advises cautious dose selection in the elderly) — so how the half-life shifts in those groups is not established on the label. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take nitisinone with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run nitisinone against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is nitisinone sold under?
We track 3 nitisinone-containing products in the U.S.: Harliku, Nityr and Orfadin. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does nitisinone come in?
Across the brands we track, nitisinone is currently marketed as tablet, capsule and suspension, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic nitisinone?
We do not currently list a generic-labelled nitisinone product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Nitisinone: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/nitisinone
- MLA
- “Nitisinone: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/nitisinone.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for nitisinone on DailyMed (NIH) ↗.