Nityr 10mg Tablets
Overview
What is this medicine?
How to Use This Medicine
To ensure you get the most benefit from your medication, follow these steps:
Take your medication exactly as directed by your doctor. Read all the information provided with your prescription and follow the instructions carefully.
You can take your medication with or without food.
Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start feeling well.
If you have difficulty swallowing the tablet whole, you can dissolve it in room temperature water using an oral syringe. Alternatively, if you can swallow soft foods, you can crush the tablet and mix it with applesauce. However, do not mix the medication with any other liquids or foods.
Before mixing your medication, wash your hands thoroughly.
If you dissolve the tablet in water, take it within 24 hours of mixing. If you mix it with applesauce, take it within 2 hours of mixing. Do not store the mixture for future use.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication:
Store the tablets in their original container at room temperature, keeping the cap tightly closed.
Keep the container in a dry place, away from the bathroom.
If you have mixed the medication with water or applesauce, store it at room temperature, away from direct sunlight.
What to Do If You Miss a Dose
If you miss a dose, follow these guidelines:
Take the missed dose as soon as you remember.
If it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule.
Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Adhere strictly to a low-tyrosine and low-phenylalanine diet as prescribed by your doctor or dietitian. This diet is crucial for preventing high tyrosine levels and associated side effects.
- Take the medication consistently at the same time each day.
- Do not stop taking nitisinone without consulting your doctor, as this can lead to a rapid increase in toxic metabolites and severe complications.
- Attend all scheduled appointments for blood tests and eye exams.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
Side Effects
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Changes in eyesight, eye pain, or severe eye irritation
Sensitivity to bright light
Confusion, difficulty focusing, or changes in behavior
Redness, irritation, pain, or thick skin on the palms of the hands or soles of the feet
Signs of infection, such as:
+ Fever
+ Chills
+ Sore throat (may indicate a low white blood cell count)
Unexplained bruising or bleeding (may indicate a low platelet count)
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any side effects that bother you or do not go away, contact your doctor or seek medical help.
Reporting Side Effects
If you have questions about side effects or want to report any, you can:
Call your doctor for medical advice
Contact the FDA at 1-800-332-1088
* Report side effects online at https://www.fda.gov/medwatch
Seek Immediate Medical Attention If You Experience:
- Changes in vision (e.g., sensitivity to light, eye pain, blurry vision, white spots on eyes)
- Skin changes (e.g., thickening of skin, rash, itching)
- Unexplained fever, chills, or signs of infection (may indicate low white blood cell count)
- Unusual bleeding or bruising (may indicate low platelet count)
- Yellowing of skin or eyes (jaundice)
- Dark urine or pale stools
- Swelling in legs or abdomen
- Increased fatigue or weakness
Before Using This Medicine
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
Potential interactions with other medications or health conditions. This medication may affect or be affected by other drugs or health problems, so it is crucial to disclose all relevant information.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products, such as herbal supplements
Vitamins
Any existing health problems
Carefully review your medications and health conditions to confirm that it is safe to take this medication in conjunction with them. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions you have with your doctor.
Additionally, your doctor may recommend regular urine tests to check for any potential issues.
To monitor for any potential eye problems, follow your doctor's instructions for scheduling an eye exam.
Adhere to the personalized diet plan that your doctor has recommended for you.
If you are pregnant, planning to become pregnant, or are breastfeeding, notify your doctor immediately. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Exaggerated side effects, particularly severe hypertyrosinemia symptoms (e.g., severe ocular symptoms, neurological changes, skin lesions)
- Increased risk of liver or kidney dysfunction
What to Do:
Seek immediate medical attention. Contact a poison control center (Call 1-800-222-1222). Management is supportive, focusing on managing symptoms and monitoring blood levels.
Drug Interactions
Moderate Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir): May increase nitisinone levels. Monitor for increased adverse effects.
- Strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin, St. John's Wort): May decrease nitisinone levels. Monitor for decreased efficacy.
Monitoring
Baseline Monitoring
Rationale: To confirm diagnosis and establish baseline for therapeutic efficacy.
Timing: Prior to initiation of therapy
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy
Rationale: To establish baseline and monitor for hypertyrosinemia, a common side effect.
Timing: Prior to initiation of therapy
Rationale: To assess baseline hepatic function and monitor for potential hepatotoxicity.
Timing: Prior to initiation of therapy
Rationale: To assess baseline renal function.
Timing: Prior to initiation of therapy
Rationale: To assess baseline hematologic status and monitor for leukopenia/thrombocytopenia.
Timing: Prior to initiation of therapy
Rationale: To establish baseline and monitor for ocular symptoms associated with hypertyrosinemia.
Timing: Prior to initiation of therapy
Routine Monitoring
Frequency: Weekly for the first month, then monthly or as clinically indicated until stable, then every 3-6 months.
Target: Undetectable or normalized
Action Threshold: If elevated, consider dose adjustment or adherence issues.
Frequency: Weekly for the first month, then monthly or as clinically indicated until stable, then every 3-6 months.
Target: 40-90 micromol/L
Action Threshold: If outside range, adjust dose. If too low, consider increasing dose or adherence. If too high, consider decreasing dose.
Frequency: Weekly for the first month, then monthly or as clinically indicated until stable, then every 3-6 months.
Target: <500 micromol/L (or as per dietary guidelines)
Action Threshold: If persistently >500-700 micromol/L, consider dietary adjustments (tyrosine/phenylalanine restriction) or nitisinone dose adjustment.
Frequency: Monthly for the first 6 months, then every 3-6 months or as clinically indicated.
Target: Within normal limits
Action Threshold: Significant elevations may indicate liver dysfunction; investigate cause, consider dose adjustment.
Frequency: Every 3-6 months or as clinically indicated.
Target: Within normal limits
Action Threshold: Significant elevations may indicate renal dysfunction; investigate cause.
Frequency: Monthly for the first 6 months, then every 3-6 months or as clinically indicated.
Target: Within normal limits
Action Threshold: Significant decreases in WBC or platelets may indicate myelosuppression; investigate cause, consider dose adjustment.
Frequency: Every 6-12 months, or if visual symptoms develop.
Target: Normal findings
Action Threshold: Presence of corneal opacities, photophobia, or other ocular symptoms may indicate hypertyrosinemia; adjust diet/nitisinone dose.
Symptom Monitoring
- Visual disturbances (e.g., photophobia, eye pain, corneal opacities)
- Skin changes (e.g., hyperkeratosis, rash)
- Neurological symptoms (e.g., developmental delay, peripheral neuropathy)
- Signs of liver dysfunction (e.g., jaundice, ascites, easy bruising)
- Signs of renal dysfunction (e.g., edema, changes in urine output)
- Signs of infection (e.g., fever, sore throat) due to potential leukopenia
- Unusual bleeding or bruising due to potential thrombocytopenia
Special Patient Groups
Pregnancy
Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited human data are available. Animal studies have shown developmental toxicity (e.g., skeletal malformations, reduced fetal weight) at doses similar to or higher than clinical exposure.
Trimester-Specific Risks:
Lactation
It is unknown if nitisinone is excreted in human milk. Due to the potential for serious adverse reactions in a breastfed infant, a decision should be made whether to discontinue breastfeeding or to discontinue the drug, taking into account the importance of the drug to the mother.
Pediatric Use
Nitisinone is indicated for pediatric patients of all ages with HT-1. Dosing is weight-based (0.5 mg/kg/day initially) and adjusted based on succinylacetone and nitisinone levels. Close monitoring of growth, development, and tyrosine levels is essential.
Geriatric Use
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, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Clinical Information
Clinical Pearls
- Nitisinone therapy must always be accompanied by a strict low-tyrosine and low-phenylalanine diet to prevent hypertyrosinemia and its associated complications (e.g., ocular symptoms, skin lesions, neurological issues).
- Regular monitoring of plasma succinylacetone, nitisinone, and tyrosine levels is critical for guiding dose adjustments and ensuring therapeutic efficacy and safety.
- Patients should be educated on the importance of adherence to both medication and diet, as non-adherence can lead to severe and rapid clinical deterioration.
- Ophthalmologic examinations are essential to monitor for corneal opacities and other ocular symptoms related to elevated tyrosine levels.
- Nitisinone is an orphan drug and is very expensive; patient assistance programs are often available through the manufacturer.
Alternative Therapies
- Liver transplantation (curative, but associated with significant risks and lifelong immunosuppression; typically reserved for patients who fail medical management or develop hepatocellular carcinoma).