Nitisinone is used to treat a certain inherited disorder (hereditary tyrosinemia type 1, also known as HT-1). HT-1 is usually discovered in infants and needs lifelong treatment. This condition is caused by a shortage of a certain natural substance that is needed to break down a nutrient (tyrosine) found in food. This effect causes a build-up of too much tyrosine and related substances in the liver. Nitisinone works by helping to prevent the formation and build-up of several toxic substances that cause damage to the liver, kidneys, and nervous system. This drug must be used along with a diet low in protein, tyrosine, and phenylalanine.
For children who are unable to swallow capsules, the capsules may be opened and the contents mixed in a small amount of water immediately before use. Make sure the child swallows the entire dose.
The dosage is based on weight, medical condition, and response to treatment.
Take this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.
It is very important that patients taking this medication follow a special diet low in protein, tyrosine, and phenylalanine. Consult your doctor, pharmacist, or dietician for more details. (See also Drug Interactions and Precautions sections.)
Nitisinone can increase tyrosine levels and cause eye problems. Patients should have an eye test (slit-lamp examination) before using this medication so that later the doctor can see whether there have been changes. (See also Side Effects and Precautions sections.)
Remember that the doctor has prescribed this medication because he or she has judged that the benefit is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may rarely cause a low number of blood cells such as white cells and platelets. This effect can decrease your body's ability to fight an infection or cause easy bruising/bleeding. Tell your doctor immediately if you develop any of the following unlikely symptoms: signs of infection (such as fever, chills, persistent sore throat), easy bruising/bleeding.
Your condition and this medication can cause liver problems. Tell the doctor immediately if any of these symptoms of liver problems occur: severe stomach/abdominal pain, persistent nausea or vomiting, yellowing eyes/skin, dark urine.
Your condition and this medication can cause high levels of tyrosine in the blood. Therefore, it is very important to follow the low protein/low tyrosine diet recommended by your doctor. See also Precautions section. Too much tyrosine may cause skin, eye, or brain problems. Tell the doctor immediately if any of these symptoms occur: eye redness/itching/discharge, vision changes, eye pain, eye sensitivity (especially to light), dry/itchy skin, sores on palms of hands/soles of feet, developmental delays (such as holding head up, rolling over, crawling).
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact the doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before giving nitisinone, tell the doctor or pharmacist if your child is allergic to it; or if your child has any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell the doctor or pharmacist your child's medical history, especially of: eye problems (such as cataracts, corneal ulcers).
Patients taking this medication are at risk for developing high levels of tyrosine in the blood, possibly leading to eye, skin, and nervous system problems. (See Side effects section.) To decrease the risk of high tyrosine levels, patients should follow a diet low in tyrosine and phenylalanine. Avoid foods and beverages that contain aspartame or are high in tyrosine or phenylalanine. Foods high in tyrosine include soy products, turkey, fish, avocados, bananas, yogurt, and lima beans. Foods high in phenylalanine include milk, chicken, eggs, cheese, peanut butter. (See also Drug Interactions section.)
It is not known whether this drug passes into breast milk. If you are taking this medication and wish to breast-feed, consult your doctor first.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Many foods, drugs, or supplements may contain aspartame, tyrosine, or phenylalanine, which must be limited in patients taking this drug. Check the labels on all products (especially artificially sweetened products) for aspartame, tyrosine and phenylalanine content. Consult your doctor, pharmacist, or dietician for more details.
If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Laboratory and/or medical tests (such as compete blood count, liver function tests, blood and urine tests for tyrosine and related substances) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store in the refrigerator. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised May 2014. Copyright(c) 2014 First Databank, Inc.
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