nitisinone at a glance
Medicine class
Inhibitor of 4-hydroxyphenylpyruvate dioxygenase, an enzyme in tyrosine metabolism.
Licensed uses
Hereditary tyrosinaemia type 1 in adults and children, and alkaptonuria in adults.
Diet
People with hereditary tyrosinaemia type 1 also need specialist dietary restriction of tyrosine and phenylalanine.
Available forms
Hard capsules and an oral suspension are represented by the selected products.
What is nitisinone used for?
The selected products are licensed for:
Confirmed hereditary tyrosinaemia type 1 in adults and children of any age, together with dietary restriction of tyrosine and phenylalanine.
Alkaptonuria in adults; use for alkaptonuria in children is not established in the selected product information.
How does nitisinone work?
Nitisinone competitively blocks 4-hydroxyphenylpyruvate dioxygenase, an early enzyme in tyrosine breakdown. This prevents formation of toxic succinylacetone-related metabolites in hereditary tyrosinaemia type 1 and reduces homogentisic acid formation in alkaptonuria. Blocking the pathway also raises tyrosine, which explains the need for dietary and eye monitoring.
nitisinone preparations and strengths
Capsule
Route: Oral
Strengths: 2 mg, 5 mg, 10 mg, 20 mg
Oral suspension
Route: Oral
Strengths: 4 mg/mL
How to take nitisinone
Take nitisinone exactly as prescribed by the specialist team. Do not change or stop treatment without discussing it with them.
Shake the oral suspension vigorously before measuring it with the supplied oral syringe.
Give the suspension directly into the mouth without dilution and empty the syringe slowly to reduce choking risk.
The oral suspension should be taken with food.
A capsule may be opened and mixed with a small amount of water, apple juice, suitable soft food or formula immediately before taking.
If capsules are started with food, keep taking them in the same way consistently.
nitisinone side effects
Common or expected effects
- Raised blood tyrosine levels.
- Eye pain, light sensitivity, conjunctivitis, corneal inflammation or clouding; eye effects are particularly frequent in alkaptonuria.
- Reduced platelet or white-cell counts in hereditary tyrosinaemia type 1.
- Itching or rash; bronchitis and pneumonia were also reported in the alkaptonuria study.
Get urgent medical advice
- New eye pain, red eyes, light sensitivity or visual disturbance requires prompt eye assessment.
- Severe or peeling skin inflammation requires urgent medical assessment.
nitisinone in pregnancy
Human pregnancy evidence is limited and consists largely of case reports, so safety is not established. Product information states that nitisinone should be used during pregnancy only when the woman's clinical condition requires it; it crosses the placenta. Pregnancy planning or a confirmed pregnancy requires prompt review by specialist metabolic and maternity teams, without abruptly stopping treatment.
nitisinone while breastfeeding
The selected product information states that people receiving nitisinone must not breastfeed because transfer into human milk is uncertain and risk to the infant cannot be excluded. Discuss feeding plans with specialist and maternity teams before birth where possible.
nitisinone interactions
Tell the specialist team about all prescribed, over-the-counter and herbal products. Important product-specific interactions include:
Warfarin and other narrow-therapeutic-index CYP2C9 substrates
Nitisinone can increase exposure, so closer clinical or laboratory monitoring and adjustment by the prescriber may be required.
Phenytoin
Nitisinone can increase phenytoin exposure; monitoring and prescriber-led adjustment may be required.
Common questions about nitisinone
Answers are fully visible for fast scanning and source review.
Why is a special diet needed with nitisinone for hereditary tyrosinaemia type 1?
Nitisinone blocks tyrosine breakdown and therefore raises tyrosine. Restricting tyrosine and phenylalanine helps control this rise and reduce eye and other toxicity.
Why can nitisinone cause eye problems?
Raised tyrosine can deposit in or irritate the cornea, causing pain, redness, light sensitivity, inflammation or blurred vision.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.