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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Harliku
Generic Name
Nitisinone
Active Ingredient
NitisinoneCategory
4-Hydroxyphenyl-Pyruvate Dioxygenase Inhibitor [EPC]
Variants
1
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 2 mg/1 | TABLET | ORAL | 70709-112 |
Detailed information about Harliku
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Harliku, you must consult a qualified healthcare professional.
Nitisinone is a specialized 4-hydroxyphenylpyruvate dioxygenase inhibitor used to treat hereditary tyrosinemia type 1 (HT-1) and alkaptonuria. It works by preventing the buildup of toxic metabolites that cause liver and kidney damage.
For the treatment of Hereditary Tyrosinemia Type 1 (HT-1), the standard starting dose for adults is typically 1 mg/kg body weight per day, divided into two doses (morning and evening). Depending on the clinical response and the levels of succinylacetone in the blood or urine, the dose may be titrated upward. The maximum recommended dose is generally 2 mg/kg/day.
For Alkaptonuria (AKU), the dosage used in clinical trials (such as the SONIA 2 study) and approved by the EMA is 10 mg once daily. This is a much lower dose than that used for HT-1 because the goal is to reduce homogentisic acid without causing the extreme tyrosinemia seen at higher doses.
Nitisinone is approved for use in pediatric patients of all ages, including neonates. The dosing is strictly weight-based:
There are no specific dosage adjustment guidelines provided by the manufacturer for patients with renal impairment. However, since nitisinone is used to prevent renal damage in HT-1, and its primary clearance is not purely renal, standard doses are usually employed with close monitoring of kidney function markers.
Nitisinone has not been specifically studied in patients with pre-existing hepatic impairment unrelated to HT-1. In patients with HT-1 who have severe liver cirrhosis or failure, the drug is still used as it is the primary treatment for the underlying cause, but these patients require intensive monitoring by a hepatologist.
Clinical studies of nitisinone did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range.
Nitisinone should be taken exactly as prescribed by a specialist in metabolic diseases.
If a dose is missed, it should be taken as soon as the patient remembers. However, if it is nearly time for the next scheduled dose, the missed dose should be skipped. Do not double the dose to make up for a missed one, as this could lead to a temporary spike in tyrosine levels.
Data on nitisinone overdose in humans is limited. The most likely consequence of an acute overdose would be a significant increase in blood tyrosine levels, which could lead to eye irritation or skin lesions. In the event of an overdose, the patient should be monitored closely, and a low-tyrosine diet should be strictly enforced. Contact a Poison Control Center or seek emergency medical care immediately if an overdose is suspected.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance. Regular blood tests are the only way to ensure the dose is correct.
The most common side effects associated with nitisinone are actually related to the elevation of tyrosine levels rather than the drug itself.
These side effects may occur in up to 10% of patients:
> Warning: Stop taking Nitisinone and call your doctor immediately if you experience any of these.
The long-term use of nitisinone has been studied for over two decades. The primary long-term risk is the development of ocular complications if tyrosine levels are not kept within the recommended range (typically 200–500 micromol/L). There is also a theoretical risk of developmental delays if tyrosine levels are allowed to fluctuate wildly during critical periods of brain development in early childhood. However, when the diet is managed well, nitisinone is generally considered safe for lifelong use. Some studies have looked at the risk of cognitive impairment, but it is difficult to separate the effects of the underlying disease from the effects of the medication.
No FDA black box warnings for Nitisinone. However, the FDA-approved labeling includes a 'Precautions' section that is nearly as stringent, emphasizing the absolute necessity of dietary tyrosine restriction and regular ophthalmic examinations.
Report any unusual symptoms to your healthcare provider. Monitoring is a lifelong commitment for patients on nitisinone therapy.
Nitisinone is a highly specialized medication that must only be prescribed by physicians experienced in the treatment of Hereditary Tyrosinemia Type 1 or Alkaptonuria. The most critical safety point is that nitisinone is NOT a cure; it is a metabolic block that requires a strict, lifelong low-protein diet. Failure to adhere to the diet while taking nitisinone can lead to toxic levels of tyrosine in the blood, causing irreversible damage to the eyes.
No FDA black box warnings for Nitisinone.
Patients on nitisinone require intensive laboratory monitoring, especially during the first six months of life or the first few months of treatment:
Nitisinone itself does not typically cause drowsiness or impairment. However, if a patient develops eye symptoms (photophobia or blurred vision) due to high tyrosine levels, they should not drive or operate heavy machinery until the symptoms resolve and their vision is cleared by an ophthalmologist.
There is no known direct chemical interaction between nitisinone and alcohol. However, many alcoholic beverages (like beer) contain significant amounts of protein or amino acids that could interfere with the strict dietary management required for HT-1 patients. Alcohol should be discussed with a metabolic specialist.
Nitisinone should never be stopped suddenly without medical supervision. In patients with HT-1, stopping the medication will lead to the immediate return of toxic succinylacetone production, which can trigger an acute 'tyrosinemia crisis' characterized by liver failure and neurological crises (similar to porphyria). There is no 'withdrawal' in the traditional sense, but the return of the disease state is rapid and life-threatening.
> Important: Discuss all your medical conditions with your healthcare provider before starting Nitisinone.
There are currently no drugs that are strictly contraindicated for use with nitisinone based on chemical incompatibility alone. However, any medication that is known to be highly hepatotoxic (damaging to the liver) should be avoided if possible, as the liver in HT-1 patients is already compromised and sensitive.
Nitisinone is a moderate inhibitor of the enzyme CYP2C9. This enzyme is responsible for breaking down several common medications. Taking nitisinone with these drugs can cause their levels to rise, increasing the risk of toxicity:
Nitisinone also inhibits transporters known as OAT1 and OAT3 (Organic Anion Transporters). These transporters help the kidneys clear certain drugs from the blood. Interactions may occur with:
Food is the most significant 'interaction' for nitisinone patients.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. The inhibition of CYP2C9 is the most clinically significant pathway for drug interactions with nitisinone.
There are no other drugs in the 4-hydroxyphenylpyruvate dioxygenase inhibitor class commonly used in humans, so cross-sensitivity with other medications is not well-documented. However, patients should be cautious if they have had reactions to other 'triketone' herbicides, as nitisinone was originally developed from this chemical family.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Nitisinone. Dietary compliance is the most important factor in the safe use of this drug.
Nitisinone is classified as Pregnancy Category C (under the old FDA system). There are no adequate and well-controlled studies in pregnant women. Animal reproduction studies have shown that nitisinone is embryotoxic and can cause fetal abnormalities in rabbits and mice at doses similar to human clinical doses. However, in women with HT-1, untreated disease poses a significant risk of liver failure and death during pregnancy. Therefore, nitisinone is typically continued during pregnancy under the strict supervision of a metabolic specialist and an obstetrician specializing in high-risk pregnancies. Tyrosine levels must be monitored even more frequently to protect the developing fetus from hypertyrosinemia.
It is not known whether nitisinone is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants (specifically the risk of high tyrosine levels affecting the infant's development), a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Most experts recommend against breastfeeding while taking nitisinone.
Nitisinone is approved for use in the pediatric population, from birth onwards. It is the standard of care for children with HT-1. The safety and effectiveness have been well-established in clinical trials and long-term registries. The primary concern in children is ensuring that the dose is adjusted frequently as the child grows and that the restrictive diet does not lead to protein malnutrition, which can stunt growth. Specialized 'medical formulas' are used to ensure these children receive adequate nutrition.
There is very little data on the use of nitisinone in patients over age 65. Most patients with HT-1 are in the pediatric or young adult demographic. For older adults with Alkaptonuria, nitisinone is used, but clinicians should be mindful of the increased likelihood of decreased renal function and the presence of other comorbidities that might increase the risk of drug interactions (especially with CYP2C9 substrates like Warfarin).
No specific dose adjustments are provided for patients with renal impairment. However, succinylacetone causes 'Fanconi Syndrome' (a type of kidney tubule damage). Nitisinone typically improves renal function in HT-1 patients by stopping the production of this toxin. If a patient has end-stage renal disease, nitisinone is not known to be cleared by dialysis, and dosing should be managed by a specialist.
In HT-1, hepatic impairment is a feature of the disease. Nitisinone is used to treat this. However, if hepatic impairment is so severe that the liver's synthetic function is lost (e.g., very low albumin), the protein binding of nitisinone may be affected, potentially increasing the free fraction of the drug. These patients require close monitoring in a transplant center.
> Important: Special populations require individualized medical assessment and frequent laboratory monitoring.
Nitisinone is a competitive inhibitor of the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD). HPPD is a copper-containing oxygenase that catalyzes the conversion of 4-hydroxyphenylpyruvate (4-HPP) to homogentisic acid (HGA) in the catabolic pathway of tyrosine. By binding to the active site of HPPD, nitisinone prevents the formation of HGA. In Tyrosinemia Type 1, this prevents the subsequent formation of maleylacetoacetate and fumarylacetoacetate, which would otherwise spontaneously convert to the toxic succinylacetone. In Alkaptonuria, the inhibition of HPPD directly reduces the accumulation of HGA, which is the primary driver of ochronotic pathology.
The primary pharmacodynamic marker for nitisinone efficacy in HT-1 is the concentration of succinylacetone. In effective treatment, succinylacetone should become undetectable in both plasma and urine. This effect is usually achieved within 24 to 48 hours of the first dose. The secondary effect is the elevation of plasma tyrosine, which is a direct consequence of the metabolic block. The relationship between nitisinone concentration and HPPD inhibition is very potent; even low plasma concentrations are sufficient to achieve near-complete enzymatic blockade.
| Parameter | Value |
|---|---|
| Bioavailability | ~90% (estimated) |
| Protein Binding | >95% (primarily Albumin) |
| Half-life | ~54 hours (range 30-86h) |
| Tmax | 1-4 hours |
| Metabolism | Minimal hepatic CYP metabolism |
| Excretion | Primarily Renal (slow) |
Nitisinone is the first and primary member of the 4-hydroxyphenylpyruvate dioxygenase inhibitor [EPC] class used in human medicine. It is therapeutically categorized as an 'Alimentary Tract and Metabolism' product (ATC code: A16AX04). There are currently no other drugs in this specific class approved for these indications, making it a unique orphan medication.
Common questions about Harliku
Nitisinone is primarily used to treat a rare genetic condition called hereditary tyrosinemia type 1 (HT-1) in both children and adults. It works by blocking the breakdown of the amino acid tyrosine at a specific point, which prevents the body from creating toxic chemicals like succinylacetone that damage the liver and kidneys. Additionally, it is approved in many regions for the treatment of Alkaptonuria, a condition where the body accumulates homogentisic acid, leading to severe joint and heart problems. Because it blocks the tyrosine pathway, it must always be used alongside a very specific low-protein diet. Without this medication, HT-1 is often fatal in early childhood due to liver failure.
The most common side effects are actually related to high levels of tyrosine in the blood, which happens if the patient does not follow their strict diet while taking the drug. These 'tyrosine-related' side effects mostly affect the eyes and include eye pain, redness, sensitivity to light, and blurred vision caused by crystals forming in the cornea. Other common side effects can include a decrease in white blood cell counts (leukopenia) or platelets (thrombocytopenia), which might make you more prone to infections or bruising. Some patients also report skin rashes or headaches during the start of treatment. Regular blood tests and eye exams are necessary to manage these risks effectively.
While there is no known direct chemical interaction between alcohol and nitisinone, drinking alcohol is generally discouraged for patients with tyrosinemia type 1. This is because alcohol can place additional stress on a liver that may already have underlying damage from the disease. Furthermore, many alcoholic beverages contain proteins or amino acids that could interfere with the very strict low-tyrosine diet required for the medication to work safely. If you are an adult being treated for Alkaptonuria, you should still consult your metabolic specialist before consuming alcohol. Always prioritize the dietary restrictions that have been set by your healthcare team.
Nitisinone is generally only used during pregnancy if the potential benefit to the mother outweighs the potential risk to the fetus. Animal studies have shown that high doses of the drug can cause fetal harm, but in women with HT-1, stopping the drug could lead to life-threatening liver failure. If a woman on nitisinone becomes pregnant, she must be managed by a high-risk obstetrician and a metabolic specialist. They will monitor her tyrosine levels very closely to try and keep them in a safe range for the baby's development. Breastfeeding is usually not recommended while taking this medication because it is unknown if the drug passes into breast milk.
Nitisinone begins to work very quickly after the first dose is administered. In patients with tyrosinemia type 1, the toxic metabolite succinylacetone typically drops significantly and may even become undetectable in the blood and urine within 24 to 48 hours. However, the physical improvements in liver and kidney function may take several weeks or months to become fully apparent. It is a lifelong medication, and its 'work' is a continuous process of preventing toxin buildup. Regular monitoring is required throughout the patient's life to ensure the drug remains effective and the dose is adjusted as the patient grows or their weight changes.
No, you should never stop taking nitisinone suddenly unless specifically directed by a metabolic specialist. For patients with HT-1, the medication is the only thing preventing the production of lethal toxins in the body. If the drug is stopped, these toxins (like succinylacetone) will return almost immediately, which can cause a rapid and severe 'tyrosinemia crisis.' This can lead to acute liver failure, intense nerve pain, and even paralysis or death. If you are having trouble with side effects or the cost of the medication, talk to your doctor immediately rather than stopping the dose on your own.
If you miss a dose of nitisinone, you should take it as soon as you remember. However, if it is almost time for your next scheduled dose, you should skip the missed dose and simply take the next one at the regular time. Do not take two doses at once to 'catch up,' as this could cause a temporary spike in your tyrosine levels, which may irritate your eyes. Because nitisinone has a very long half-life (it stays in your system for a long time), a single missed dose is rarely an emergency, but you should still try to be as consistent as possible to maintain stable levels.
Weight gain is not a commonly reported direct side effect of nitisinone itself. However, children with HT-1 often experience 'catch-up growth' and healthy weight gain once they start treatment because their bodies are finally able to process nutrients without being poisoned by toxic metabolites. If an adult experiences significant or unexplained weight gain while on nitisinone, it should be discussed with a doctor, as it could be related to other factors like diet or thyroid function. It is important to remember that the diet used with nitisinone is very specific and must be balanced by a specialized dietitian.
Nitisinone can interact with certain other medications because it inhibits an enzyme called CYP2C9. This means it can slow down the removal of drugs like warfarin (a blood thinner), phenytoin (for seizures), and some diabetes medications, potentially making them reach toxic levels in your blood. It also affects how the kidneys clear certain anti-inflammatory drugs (NSAIDs) like ibuprofen. You must provide your doctor and pharmacist with a complete list of all medications, over-the-counter drugs, and herbal supplements you are taking. They will monitor you closely and may need to adjust the doses of your other medications while you are on nitisinone.
Yes, nitisinone is available as a generic medication in several countries, including the United States. While it was originally sold only under the brand name Orfadin, there are now other versions available, such as Nityr (a tablet formulation) and various generic capsules. Generic versions are required by the FDA to be 'bioequivalent' to the brand-name drug, meaning they work the same way in the body. Because this is an orphan drug for a rare disease, you may need to obtain it through a specialized 'specialty pharmacy' rather than a standard local drugstore. Your doctor or insurance provider can help you find the most cost-effective version.
Other drugs with the same active ingredient (Nitisinone)