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Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





Nitisinone is used, along with dietary restriction of certain amino acids (tyrosine and phenylalanine), to treat a genetic metabolism disorder called hereditary tyrosinemia type 1 (HT-1). This condition, usually seen in children, is caused by a deficiency in an enzyme that metabolizes tyrosine.

How To Use

Take this medication by mouth usually twice daily on an empty stomach (at least 1 hour before meals); or as directed by your doctor. The dosage is based on your weight, medical condition, and response to therapy. If you have difficulty swallowing this medication, the capsules may be opened and the contents sprinkled into a small amount of water, formula, or applesauce immediately before use. Do not make up a supply in advance.

Side Effects

Headache, diarrhea, or increased thirst may occur. If any of these effects persist or worsen, notify your doctor. Tell your doctor immediately if any of these serious side effects occur: stomach pain, dark urine, yellowing eyes or skin. Tell your doctor immediately if any of these unlikely but serious side effects occur: eye problems (e.g., redness, swelling, burning, vision changes, light sensitivity, or pain). Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: rash, persistent sore throat or fever, easy bruising or bleeding, seizures. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor your medical history, especially of: other metabolism problems (e.g., porphyria), any allergies. Limit your intake of foods that have a high amount of tyrosine and phenylalanine (e.g., high protein, aspartame). Consult your doctor or a dietician for details on a low protein diet and for information on products that may contain aspartame. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known whether this drug passes into breast milk. Because of the potential risk to the infant, breast-feeding while using this drug is not recommended.

Drug Interactions

Tell your doctor of all prescription and nonprescription medication you may use. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately.


Do not share this medication with others. Laboratory and/or medical tests (e.g., blood counts, eye exams, alpha-fetoprotein levels, tyrosine levels) may be performed to monitor your progress or side effects. It is very important to keep all regularly scheduled medical and laboratory appointments.

Missed Dose

If you miss a dose, use 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 a refrigerator between 36 and 46 degrees F (2 and 8 degrees C) away from light and moisture.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).