Specialty Drug


IDURSULFASE is used to replace an enzyme that is missing in patients with Hunter syndrome. It is not a cure. Compare enzyme replacement therapies.

What is Idursulfase?

Commonly Used Brand Name(s)Elaprase

Therapeutic ClassificationsEnzyme Replacement

Pharmacologic ClassificationsEnzyme



Blackbox WarningTOP

Intravenous route (Solution)

Life-threatening anaphylactic reactions, presenting as respiratory distress, hypoxia, hypotension, urticaria, and/or angioedema of throat or tongue have occurred in some patients during and up to 24 hours after idursulfase infusions, regardless of duration of the course of treatment. Closely observe patients during and after idursulfase administration and be prepared to manage anaphylaxis. Inform patients of the signs and symptoms of anaphylaxis and have them seek immediate medical care should symptoms occur. Patients with compromised respiratory function or acute respiratory disease may be at risk of serious acute exacerbation of their respiratory compromise due to hypersensitivity reactions, and require additional monitoring .


Idursulfase injection is used to treat Hunter syndrome (Mucopolysaccharidosis II, MPS II), a rare condition that is most often seen in males. Hunter syndrome is an inherited disease in which the breakdown of a certain chemical in the body (mucopolysaccharide) is defective due to the lack or absence of an enzyme called iduronate-2-sulfatase.

Idursulfase improves signs and symptoms in patients, especially walking capacity, by replacing the missing enzyme in Hunter syndrome.

This medicine is available only with your doctor's prescription.

Proper UseTOP

A nurse or other trained health professional will give you or your child this medicine in a hospital. This medicine is given through a needle placed in one of your veins.

This medicine is usually given one time each week. The medicine is given slowly, so the needle will remain in place for a few hours. You or your child may also receive medicines to help prevent possible allergic reactions to the injection.

Before UsingTOP

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of idursulfase injection in children. However, safety and efficacy have not been established in children younger than 16 months of age.


Appropriate studies have not been performed on the relationship of age to the effects of idursulfase injection in the geriatric population. Safety and efficacy have not been established.


Pregnancy CategoryExplanation
All TrimestersCAnimal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast FeedingTOP

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug InteractionsTOP

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other InteractionsTOP

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical ProblemsTOP

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Fluid overload (too much fluid in the blood) or
  • Heart disease or
  • Illness with fever or
  • Lung disease or breathing problems—Use with caution. May increase risk of developing life-threatening complications.


It is very important that your doctor check your or your child's progress at regular visits. This will allow your doctor to see if the medicine is working properly and check you for unwanted effects that may be caused by this medicine.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Tell your doctor or nurse right away if you or your child have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after you or your child get the injection.

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