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Idursulfase Side Effects

Commonly reported side effects of idursulfase include pruritus, dyspepsia, urticaria, pruritic rash, abscess, infusion related reaction, chest wall pain, and visual disturbance. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to idursulfase: intravenous solution

In addition to its needed effects, some unwanted effects may be caused by idursulfase. In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking idursulfase, check with your doctor or nurse immediately:

More common
  • Bone or muscle pain
  • chest pain
  • chills
  • cough
  • fast, pounding, or irregular heartbeat or pulse
  • feeling of warmth
  • fever
  • headache
  • hives or welts
  • itching
  • rash
  • redness of the face, neck, arms, and occasionally, upper chest
  • redness of the skin
  • sneezing
  • sore throat
  • tightness in the chest
  • unusual tiredness or weakness
Less common
  • Blurred vision
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • sweating
Incidence not known
  • Difficulty with swallowing
  • dilated neck veins
  • extreme fatigue
  • heart stops
  • irregular breathing
  • no breathing
  • no pulse or blood pressure
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • unconscious
  • weight gain

Some of the side effects that can occur with idursulfase may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Change in hearing
  • diarrhea
  • ear drainage
  • earache or pain in the ear
Less common
  • Nausea
  • vomiting

For Healthcare Professionals

Applies to idursulfase: intravenous solution


During clinical trials, the most common side effects were hypersensitivity reactions, and included rash, urticaria, pruritus, flushing, pyrexia, and headache. The most common serious side effects after idursulfase therapy included hypoxic episodes.[Ref]


Very common (10% or more): Hypersensitivity reactions (up to 69%)
Common (1% to 10%): Anaphylactic reactions (with symptoms of bronchospasm, cyanosis, dyspnea, erythema, edema [facial and peripheral], flushing, rash, respiratory distress, urticaria, vomiting, and wheezing; 10%)
Frequency not reported: Serious hypersensitivity reactions (including anaphylaxis, life-threatening reactions, respiratory distress, hypoxia, hypotension, urticaria, and/or angioedema of the throat or tongue)
Postmarketing reports: Late-emergent signs/symptoms of anaphylactic reactions, repeated anaphylaxis over 2- to 4-month period[Ref]

In clinical trials, 15% of patients had hypersensitivity reactions involving side effects in at least 2 of the following 3 body systems: cardiovascular, cutaneous, or respiratory. Such reactions occurred during 0.3% of infusions.

During the extension trial, common hypersensitivity reactions included rash (23%), pyrexia (9%), flushing (7%), erythema (7%), nausea (5%), dizziness (5%), vomiting (5%), and hypotension (5%).

Serious hypersensitivity reactions (including anaphylaxis) have been reported during and up to 24 hours after infusion. Some reactions were life-threatening and included respiratory distress, hypoxia, hypotension, urticaria, and/or angioedema of the throat or tongue, regardless of treatment duration.

During postmarketing experience, late-emergent signs/symptoms of anaphylactic reactions have been reported up to 24 hours after initial therapy and recovery from an initial anaphylactic reaction. Also, repeated anaphylaxis has been reported over a 2- to 4-month period, up to several years after the start of therapy.[Ref]


Forty-one percent of patients who tested positive for anti-idursulfase IgG antibodies also tested positive for uptake neutralizing antibodies or activity neutralizing antibodies (at least once).[Ref]

Very common (10% or more): Anti-idursulfase IgG antibodies (51%), uptake or activity neutralizing antibodies (21%)
Frequency not reported: Abscess[Ref]

Nervous system

Very common (10% or more): Headache (28%)
Common (1% to 10%): Dizziness (5%)
Rare (less than 0.1%): Seizure with loss of consciousness[Ref]

Respiratory distress, hypoxia, cyanosis, and seizure with loss of consciousness during idursulfase infusion were reported in a patient with a tracheostomy, severe airway disease, and acute febrile illness.[Ref]


Very common (10% or more): Pruritus (25%), rash (up to 23%), urticaria (16%)
Common (1% to 10%): Erythema (7%)
Frequency not reported: Superficial injury, skin disorders, pruritic rash[Ref]


Very common (10% or more): Flushing (up to 16%), fatigue (13%)
Common (1% to 10%): Chills (9%), pyrexia (9%)
Rare (less than 0.1%): Infection (at least 1 case)
Frequency not reported: Malaise, adverse events resulting from injury[Ref]


Very common (10% or more): Musculoskeletal pain (13%)
Frequency not reported: Arthralgia, limb pain, musculoskeletal dysfunction, chest wall musculoskeletal pain[Ref]


During postmarketing experience, serious side effects that resulted in death included cardiorespiratory arrest and cardiac failure.[Ref]

Common (1% to 10%): Tachycardia (9%), hypotension (5%)
Rare (less than 0.1%): Cardiac arrhythmia (at least 1 case)
Frequency not reported: Hypertension, atrial abnormality
Postmarketing reports: Cardiorespiratory arrest, cardiac failure[Ref]


Common (1% to 10%): Cough (9%)
Rare (less than 0.1%): Pulmonary embolism (at least 1 case)
Frequency not reported: Hypoxia, cyanosis, wheezing
Postmarketing reports: Respiratory failure, respiratory distress, pneumonia[Ref]

Respiratory distress, hypoxia, cyanosis, and seizure with loss of consciousness during idursulfase infusion were reported in a patient with a tracheostomy, severe airway disease, and acute febrile illness.

During postmarketing experience, serious side effects that resulted in death included respiratory failure, respiratory distress, and pneumonia.[Ref]


Common (1% to 10%): Diarrhea (9%), nausea (5%), vomiting (5%)
Frequency not reported: Dyspepsia[Ref]


Frequency not reported: Anxiety/irritability[Ref]


Frequency not reported: Visual disturbances[Ref]


Frequency not reported: Infusion site edema[Ref]


1. "Product Information. Elaprase (idursulfase)." Shire US Inc, Florence, KY.

Not all side effects for idursulfase may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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