Orfadin Side Effects Center

Last updated on RxList: 5/9/2022
Orfadin Side Effects Center

What Is Orfadin?

Orfadin (nitisinone) is a hydroxyphenyl-pyruvate dioxygenase inhibitor used to treat a rare genetic condition called hereditary tyrosinemia type 1 (HT-1). HT-1 is a metabolic disorder that occurs when the body does not produce enough of an enzyme that breaks down proteins from certain foods. This condition occurs most often in babies. Orfadin works by helping to prevent the formation and build-up of several toxic substances that cause damage to the liver, kidneys, and nervous system. Many people using Orfadin do not have serious side effects.

What Are Side Effects of Orfadin?

Side effects of Orfadin may include:

  • cough
  • muscle aches
  • itching or peeling of your skin
  • diarrhea
  • nausea
  • constipation
  • nervousness
  • trouble sleeping
  • thirst
  • mild stomach pain, or
  • diarrhea

Orfadin may rarely cause the side effect of a low number of blood cells such as white cells and platelets. Tell your doctor if you have signs of infection (such as fever, chills, persistent sore throat), or easy bruising/bleeding.

Dosage for Orfadin

The recommended dose of Orfadin is 1 to 2 mg/kg divided into two daily doses. The initial dose is 1 mg/kg/day divided for morning and evening administration.

What Drugs, Substances, or Supplements Interact with Orfadin?

Other drugs may interact with Orfadin. Tell your doctor all medications and supplements you use.

Orfadin During Pregnancy or Breastfeeding

During pregnancy, Orfadin should be used only when prescribed. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Orfadin (nitisinone) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


About how much does an adult human brain weigh? See Answer
Orfadin Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may result from not properly following your diet plan and consuming restricted foods or beverages.

Call your doctor at once if you have:

  • a sudden change in behavior, ability, or development (sitting up, crawling, walking, talking, etc);
  • easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
  • nausea, diarrhea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • vision problems;
  • eye pain, redness or swelling, burning, white or yellow patches on your eyes; or
  • calluses, peeling, or hardened skin on the palms of your hands or the soles of your feet.

Common side effects may include:

  • vision changes, your eyes may be more sensitive to light;
  • eye pain, red or puffy eyes;
  • nosebleeds;
  • increased sensitivity of your eyes to light;
  • rash or itching;
  • dry or peeling skin; or
  • thinning hair.

The liquid form of nitisinone may contain glycerol and can cause headache, upset stomach, or diarrhea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Orfadin (Nitisinone Capsules and Oral Suspension)


Digestive Disorders: Common Misconceptions See Slideshow
Orfadin Professional Information


Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

ORFADIN was studied in one open-label, uncontrolled study of 207 patients with HT-1, ages 0 to 22 years at enrollment (median age 9 months), who were diagnosed with HT-1 by the presence of succinylacetone in the urine or plasma. The starting dose of ORFADIN was 0.3 to 0.5 mg/kg twice daily, and the dose was increased in some patients to 1 mg/kg twice daily based on weight, biochemical, and enzyme markers. The recommended starting dosage of ORFADIN is 0.5 mg/kg twice daily [see DOSAGE AND ADMINISTRATION]. Median duration of treatment was 22 months (range 0.1 to 80 months).

The most serious adverse reactions reported during ORFADIN treatment were thrombocytopenia, leukopenia, porphyria, and ocular/visual complaints associated with elevated tyrosine levels [see WARNINGS AND PRECAUTIONS]. Fourteen patients experienced ocular/visual events. The duration of the symptoms varied from 5 days to 2 years. Six patients had thrombocytopenia, three of which had platelet counts 30,000/microL or lower. In 4 patients with thrombocytopenia, platelet counts gradually returned to normal (duration up to 47 days) without change in ORFADIN dose. No patients developed infections or bleeding as a result of the episodes of leukopenia and thrombocytopenia.

Patients with HT-1 are at increased risk of developing porphyric crises, hepatic neoplasms, and liver failure requiring liver transplantation. These complications of HT1 were observed in patients treated with nitisinone for a median of 22 months during the clinical trial (liver transplantation 13%, liver failure 7%, malignant hepatic neoplasms 5%, benign hepatic neoplasms 3%, porphyria 1%).

The most common adverse reactions reported in the clinical trial are summarized in Table 1.

TABLE 1: Most Common Adverse Reactions in Patients with HT-1 Treated with Nitisinone*

Elevated tyrosine levels >10%
Leukopenia 3%
Thrombocytopenia 3%
Conjunctivitis 2%
Corneal opacity 2%
Keratitis 2%
Photophobia 2%
Eye pain 1%
Blepharitis 1%
Cataracts 1%
Granulocytopenia 1%
Epistaxis 1%
Pruritus 1%
Exfoliative dermatitis 1%
Dry skin 1%
Maculopapular rash 1%
Alopecia 1%
*reported in at least 1% of patients

Adverse reactions reported in less than 1% of the patients, included death, seizure, brain tumor, encephalopathy, hyperkinesia, cyanosis, abdominal pain, diarrhea, enanthema, gastrointestinal hemorrhage, melena, elevated hepatic enzymes, liver enlargement, hypoglycemia, septicemia, and bronchitis.

Read the entire FDA prescribing information for Orfadin (Nitisinone Capsules and Oral Suspension)

© Orfadin Patient Information is supplied by Cerner Multum, Inc. and Orfadin Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

Health Solutions From Our Sponsors