Idursulfase: uses, dosing, side effects & brands
Idursulfase is a medicine sold in the U.S. under one brand, for mucopolysaccharidosis ii. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats
- Mucopolysaccharidosis II
- Available as
- Solution
- Sold as
- Elaprase
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Boxed warning
- Boxed warning
How idursulfase is dosed
From the FDA label for Elaprase (application BLA125151). Other idursulfase products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended dosage is 0.5 mg per kg of body weight administered once every week as an intravenous infusion ( 2 ). 2.1 Recommended Dose The recommended dosage regimen of ELAPRASE is 0.5 mg per kg of body weight administered once weekly as an intravenous infusion. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. 2.2 Preparation Instructions Prepare and use ELAPRASE according to the following steps using aseptic technique: Determine the total volume of ELAPRASE to be administered and the number of vials needed based on the patient's weight and the recommended dose of 0.5 mg/kg. Patient's weight (kg) × 0.5 mg per kg of ELAPRASE ÷ 2 mg per mL = Total mL of ELAPRASE Total mL of ELAPRASE ÷ 3 mL per vial = Total number of vials Round up to the next whole vial to determine the total number of vials needed. Remove the required number of vials from the refrigerator to allow them to reach room temperature. Before withdrawing the ELAPRASE solution from the vial, visually inspect each vial for particulate matter and discoloration. The ELAPRASE solution should be clear to slightly opalescent and colorless. Do not use if the solution is discolored or if there is particulate matter in the solution. Do not shake the ELAPRASE solution. Withdraw the calculated volume of ELAPRASE from…
Idursulfase side effects
The most common adverse reactions occurring in at least three patients (≥9%) aged five years and older were headache, pruritus, musculoskeletal pain, urticaria, diarrhea, and cough. The most common adverse reactions occurring in at least three patients (≥10%) aged seven years and younger were pyrexia, rash, vomiting, and urticaria. In all clinical trials, the most common adverse reactions requiring medical intervention were hypersensitivity reactions, and included rash, urticaria, pruritus, flushing, pyrexia, and headache ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Takeda Pharmaceuticals U.S.A., Inc. at 1-877-TAKEDA-7 (1-877-825-3327) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 practice. The following serious adverse reactions are described below and elsewhere in the labeling: Hypersensitivity Reactions Including Anaphylaxis [see Warnings and Precautions (5.1) ] In clinical trials, the most common adverse reactions (>10%) following ELAPRASE treatment were hypersensitivity reactions, and included rash, urticaria, pruritus, flushing, pyrexia, and headache. Most hypersensitivity…
Who shouldn’t take idursulfase
None. None. ( 4 )
Every idursulfase product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Elaprase.
Idursulfase and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for idursulfase: levels in milk, effects in breastfed infants, and the drugs it would consider insteadNo information is available on the clinical use of idursulfase during breastfeeding. Because it is a large protein molecule with a molecular weight of about 76,000 Da, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant's gastrointestinal tract. If idursulfase is required by the mother, it is not a reason to discontinue breastfeeding. Until more data are available, idursulfase should be used with infant careful monitoring during breastfeeding.
National Institute of Child Health and Human Development, record revised April 15, 2026. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about idursulfase
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 2,205 reports naming idursulfase, and the FDA flagged 96% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- pyrexia445 reports
- inappropriate schedule of product administration344 reports
- cough236 reports
- pneumonia203 reports
- product availability issue190 reports
- influenza185 reports
- covid-19178 reports
- weight increased167 reports
Read these as a signal, not a rate. A report does not mean idursulfase caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
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Frequently asked questions
What is idursulfase?
Elaprase (Idursulfase) is a medication used to treat Mucopolysaccharidosis II.
Can you take idursulfase with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run idursulfase against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does idursulfase come in?
Across the brands we track, idursulfase is currently marketed as solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic idursulfase?
We do not currently list a generic-labelled idursulfase product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Idursulfase: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/idursulfase
- MLA
- “Idursulfase: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/idursulfase.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for idursulfase on DailyMed (NIH) ↗ — including its boxed warning in full.