Idursulfase side effects: what 3,978 FDA adverse event reports show
Drug class
Hydrolytic Lysosomal Glycosaminoglycan-specific Enzyme
Brand names
Elaprase
Who reports
3,978 reports · 88% serious · 684 with death outcome · 1% female
Used for
ELAPRASE is indicated for patients with Hunter syndrome (Mucopolysaccharidosis II, MPS II). ELAPRASE has been shown to improve walking capacity in patients 5 years and older. In patients 16 months to 5 years of age, no data are available to demonstrate.
What it is
ELAPRASE is a formulation of idursulfase, a purified form of human iduronate-2-sulfatase, a lysosomal enzyme. Idursulfase is produced by recombinant DNA technology in a human cell line. Idursu.
Boxed warning
RISK OF ANAPHYLAXIS Life-threatening anaphylactic reactions have occurred in some patients during and up to 24 hours after ELAPRASE infusions. Anaphylaxis, presenting as respiratory distress, hypoxia, hypotension, ur.
Causality screen of the 40 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 188 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Poor venous access | 196 | 102.0 88.9–117.1ROR 107.2 · χ² 19,136 / p <1e-300 | 99.1 EB05 88.0 · IC025 +6.1 3/3 methods agree | Not in label — unassessed | serious n=181 | no trial data cached |
| Product availability issue | 199 | 47.2 41.2–54.1ROR 49.6 · χ² 8,880 / p <1e-300 | 46.6 EB05 41.4 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious PRR 60.4 · 76% consumer | no trial data cached |
| Carpal tunnel syndrome | 84 | 31.7 25.6–39.2ROR 32.4 · χ² 2,454 / p <1e-300 | 31.3 EB05 26.1 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 24.8 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 389 | 31.2 28.4–34.3ROR 34.5 · χ² 11,315 / p <1e-300 | 31.0 EB05 28.5 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 22.2 | no trial data cached |
| Insurance issue | 78 | 27.8 22.3–34.7ROR 28.3 · χ² 1,980 / p <1e-300 | 27.5 EB05 22.8 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious PRR 33.0 · 78% consumer | no trial data cached |
| Device related infection | 78 | 26.8 21.5–33.4ROR 27.3 · χ² 1,901 / p <1e-300 | 26.5 EB05 21.9 · IC025 +4.1 3/3 methods agree | Reporting / coding artifact | serious PRR 17.8 | no trial data cached |
| Cyanosis (blue skin from low oxygen) | 71 | 23.8 18.9–30.0ROR 24.3 · χ² 1,525 / p <1e-300 | 23.6 EB05 19.3 · IC025 +4.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 16.2 | no trial data cached |
| Body temperature increased | 88 | 22.7 18.5–28.0ROR 23.2 · χ² 1,802 / p <1e-300 | 22.6 EB05 18.9 · IC025 +4.0 3/3 methods agree | Lab value / disease marker | serious PRR 17.6 | no trial data cached |
| Secretion discharge | 53 | 22.7 17.4–29.7ROR 23.0 · χ² 1,074 / p 9e-236 | 22.4 EB05 17.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 24.2 | no trial data cached |
| Respiratory disorder | 126 | 22.2 18.7–26.4ROR 22.9 · χ² 2,525 / p <1e-300 | 22.1 EB05 19.0 · IC025 +4.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 17.3 | no trial data cached |
| Ear infection | 102 | 20.3 16.8–24.6ROR 20.8 · χ² 1,850 / p <1e-300 | 20.2 EB05 17.1 · IC025 +3.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 22.4 | no trial data cached |
| Bronchospasm (airway tightening) | 55 | 20.3 15.6–26.4ROR 20.6 · χ² 988 / p 4e-217 | 20.1 EB05 16.0 · IC025 +3.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 14.3 | no trial data cached |
| Respiratory distress | 106 | 20.3 16.8–24.5ROR 20.8 · χ² 1,921 / p <1e-300 | 20.2 EB05 17.1 · IC025 +3.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 13.4 | no trial data cached |
| Complication associated with device | 50 | 20.0 15.2–26.4ROR 20.2 · χ² 881 / p 8e-194 | 19.8 EB05 15.6 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 19.9 | no trial data cached |
| Respiratory tract infection | 95 | 19.3 15.9–23.6ROR 19.8 · χ² 1,631 / p <1e-300 | 19.2 EB05 16.2 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 14.9 | no trial data cached |
| Pharyngitis | 43 | 18.2 13.5–24.6ROR 18.4 · χ² 682 / p 1e-150 | 18.0 EB05 13.9 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious PRR 14.6 · 71% consumer | no trial data cached |
| Product prescribing error | 76 | 17.0 13.6–21.2ROR 17.3 · χ² 1,124 / p 1e-246 | 16.8 EB05 13.9 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious PRR 21.8 · 82% consumer | no trial data cached |
| Body temperature decreased | 31 | 16.5 11.6–23.4ROR 16.6 · χ² 435 / p 7e-97 | 16.2 EB05 11.8 · IC025 +3.1 3/3 methods agree | Lab value / disease marker | serious PRR 11.5 | no trial data cached |
| Obstructive airways disorder | 34 | 16.1 11.5–22.5ROR 16.2 · χ² 465 / p 2e-103 | 15.8 EB05 11.7 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 10.9 | no trial data cached |
| Aspiration | 29 | 14.1 9.8–20.3ROR 14.2 · χ² 340 / p 3e-76 | 13.7 EB05 9.8 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.4 | no trial data cached |
| Productive cough (cough with phlegm) | 118 | 13.2 11.0–15.7ROR 13.5 · χ² 1,314 / p 5e-288 | 13.1 EB05 11.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 12.5 | no trial data cached |
| Choking | 48 | 13.1 9.9–17.3ROR 13.2 · χ² 522 / p 1e-115 | 12.8 EB05 9.9 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 10.0 | no trial data cached |
| Inappropriate schedule of product administration | 415 | 12.4 11.3–13.6ROR 13.7 · χ² 4,363 / p <1e-300 | 12.3 EB05 11.4 · IC025 +3.4 3/3 methods agree | Reporting / coding artifact | serious PRR 18.4 | no trial data cached |
| Restlessness | 83 | 12.0 9.7–14.8ROR 12.2 · χ² 822 / p 4e-181 | 11.8 EB05 9.7 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 10.6 | no trial data cached |
| Salivary hypersecretion | 22 | 11.6 7.7–17.6ROR 11.7 · χ² 203 / p 3e-46 | 10.8 EB05 7.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 10.3 | no trial data cached |
| Viral infection | 73 | 11.6 9.2–14.6ROR 11.8 · χ² 696 / p 1e-153 | 11.4 EB05 9.3 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.7 | no trial data cached |
| Rhinorrhoea (runny nose) | 141 | 11.6 9.8–13.6ROR 11.9 · χ² 1,350 / p 9e-296 | 11.4 EB05 9.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 17.1 | no trial data cached |
| Pallor | 59 | 11.4 8.9–14.7ROR 11.6 · χ² 550 / p 6e-122 | 11.1 EB05 8.8 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.2 | no trial data cached |
| Tachypnoea | 29 | 11.3 7.9–16.2ROR 11.4 · χ² 262 / p 4e-59 | 10.7 EB05 7.5 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Influenza | 232 | 11.0 9.7–12.4ROR 11.6 · χ² 2,095 / p <1e-300 | 10.9 EB05 9.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 11.4 | no trial data cached |
| Respiratory tract congestion | 33 | 11.0 7.8–15.4ROR 11.0 · χ² 288 / p 6e-65 | 10.4 EB05 7.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 16.5 | no trial data cached |
| Epilepsy | 63 | 10.9 8.5–13.9ROR 11.1 · χ² 556 / p 3e-123 | 10.6 EB05 8.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 | no trial data cached |
| Dental caries | 22 | 10.5 6.9–16.0ROR 10.6 · χ² 180 / p 3e-41 | 9.6 EB05 6.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 9.6 | no trial data cached |
| Oxygen saturation decreased | 111 | 10.5 8.7–12.6ROR 10.8 · χ² 945 / p 7e-208 | 10.3 EB05 8.8 · IC025 +3.0 3/3 methods agree | Lab value / disease marker | serious PRR 7.5 | no trial data cached |
| Seizure | 217 | 10.0 8.8–11.4ROR 10.5 · χ² 1,751 / p <1e-300 | 9.9 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.8 | no trial data cached |
| Treatment noncompliance | 102 | 9.9 8.2–12.0ROR 10.1 · χ² 809 / p 3e-178 | 9.7 EB05 8.2 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 9.6 · 82% consumer | no trial data cached |
| Device occlusion | 26 | 9.9 6.7–14.5ROR 9.9 · χ² 198 / p 3e-45 | 9.1 EB05 6.3 · IC025 +2.4 3/3 methods agree | Reporting / coding artifact | serious n=26 | no trial data cached |
| Poor quality sleep | 39 | 9.6 7.0–13.2ROR 9.7 · χ² 292 / p 7e-66 | 9.1 EB05 6.8 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious PRR 11.2 | no trial data cached |
| Pyrexia (fever) | 617 | 9.4 8.7–10.1ROR 10.9 · χ² 4,696 / p <1e-300 | 9.4 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.9 | no trial data cached |
| Acute respiratory failure | 34 | 9.4 6.7–13.1ROR 9.4 · χ² 246 / p 1e-55 | 8.7 EB05 6.4 · IC025 +2.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.1 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Pyrexia (fever) | 617 | 9.4 8.7–10.1ROR 10.9 · χ² 4,696 / p <1e-300 | 9.4 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.9 | no trial data cached |
| Product dose omission issue | 494 | 9.2 8.4–9.9ROR 10.3 · χ² 3,625 / p <1e-300 | 9.1 EB05 8.4 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 20.6 | no trial data cached |
| Inappropriate schedule of product administration | 415 | 12.4 11.3–13.6ROR 13.7 · χ² 4,363 / p <1e-300 | 12.3 EB05 11.4 · IC025 +3.4 3/3 methods agree | Reporting / coding artifact | serious PRR 18.4 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 389 | 31.2 28.4–34.3ROR 34.5 · χ² 11,315 / p <1e-300 | 31.0 EB05 28.5 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 22.2 | no trial data cached |
| Cough | 311 | 5.9 5.3–6.5ROR 6.3 · χ² 1,265 / p 2e-277 | 5.8 EB05 5.3 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.3 | no trial data cached |
| Pneumonia (lung infection) | 300 | 4.9 4.4–5.5ROR 5.2 · χ² 939 / p 1e-206 | 4.9 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.3 | no trial data cached |
| Death | 271 | 1.7 1.5–1.9ROR 1.7 · χ² 73 / p 6e-18 | 1.7 EB05 1.5 · IC025 +0.5 | Outcome field, not a reaction | serious PRR 1.1 | no trial data cached |
| Influenza | 232 | 11.0 9.7–12.4ROR 11.6 · χ² 2,095 / p <1e-300 | 10.9 EB05 9.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 11.4 | no trial data cached |
| Seizure | 217 | 10.0 8.8–11.4ROR 10.5 · χ² 1,751 / p <1e-300 | 9.9 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.8 | no trial data cached |
| Covid-19 | 207 | 6.2 5.4–7.0ROR 6.5 · χ² 898 / p 1e-197 | 6.1 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 | no trial data cached |
| Malaise (feeling unwell) | 199 | 2.4 2.1–2.7ROR 2.5 · χ² 162 / p 2e-37 | 2.4 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Product availability issue | 199 | 47.2 41.2–54.1ROR 49.6 · χ² 8,880 / p <1e-300 | 46.6 EB05 41.4 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious PRR 60.4 · 76% consumer | no trial data cached |
| Poor venous access | 196 | 102.0 88.9–117.1ROR 107.2 · χ² 19,136 / p <1e-300 | 99.1 EB05 88.0 · IC025 +6.1 3/3 methods agree | Not in label — unassessed | serious n=181 | no trial data cached |
| Weight increased (weight gain) | 192 | 4.5 4.0–5.2ROR 4.7 · χ² 533 / p 4e-118 | 4.5 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Nasopharyngitis (common cold) | 185 | 5.3 4.6–6.1ROR 5.5 · χ² 643 / p 4e-142 | 5.2 EB05 4.6 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 7.4 | no trial data cached |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Poor venous access — n=196, PRR 102.0
- Carpal tunnel syndrome — n=84, PRR 31.7
- Infusion related reaction — n=389, PRR 31.2
- Insurance issue — n=78, PRR 27.8
- Secretion discharge — n=53, PRR 22.7
- Pharyngitis — n=43, PRR 18.2
- Obstructive airways disorder — n=34, PRR 16.1
- Aspiration — n=29, PRR 14.1
- Productive cough — n=118, PRR 13.2
- Choking — n=48, PRR 13.1
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Idursulfase?
In FDA FAERS, the most frequently co-reported reaction terms for Idursulfase are pyrexia, infusion related reaction, cough, pneumonia, influenza, seizure. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Idursulfase have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: RISK OF ANAPHYLAXIS Life-threatening anaphylactic reactions have occurred in some patients during and up to 24 hours after ELAPRASE infusions. Anaphylaxis, presenting as respiratory distress, hypoxia, hypotension, ur.
Do FAERS signals prove that Idursulfase causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 60cba843-5aab-4dd7-96dc-66648d413be3, effective 20250415; matched on
openfda.generic_name.exact:"IDURSULFASE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 228 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.