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. 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.

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. Other drugs may interact with Orfadin. Tell your doctor all medications and supplements you use. During pregnancy, Orfadin should be used only when prescribed. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

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

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;
  • red or puffy eyes;
  • nosebleeds;
  • increased sensitivity of your eyes to light;
  • mild rash or itching;
  • dry 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.