Ferumoxytol side effects: what 1,902 FDA adverse event reports show
Drug class
Parenteral Iron Replacement
Who reports
1,902 reports · 62% serious · 131 with death outcome · 70% female
Used for
Ferumoxytol is indicated for the treatment of iron deficiency anemia (IDA) in adult patients: • who have intolerance to oral iron or have had unsatisfactory response to oral iron or • who have chronic kidney disease (CKD). Ferumoxytol is an iron replac.
What it is
Ferumoxytol is an iron replacement product containing ferumoxytol for intravenous infusion. Ferumoxytol is a non-stoichiometric magnetite (superparamagnetic iron oxide) coated with polyglucose sorbitol carboxymethylether. The overall colloidal particle size is 17 to 31 nm in diameter.
Boxed warning
RISK FOR SERIOUS HYPERSENSITIVITY/ANAPHYLAXIS REACTIONS Fatal and serious hypersensitivity reactions including anaphylaxis have occurred in patients receiving ferumoxytol. Initial symptoms may include hypotension, syncope, unresponsiveness, cardiac/cardiorespiratory arrest.
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. 14 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 |
|---|---|---|---|---|---|---|
| Unresponsive to stimuli | 139 | 59.9 51.0–70.3ROR 64.5 · χ² 7,956 / p <1e-300 | 59.1 EB05 51.3 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious PRR 56.9 · 92% clinician | no trial data cached |
| Anaphylactic reaction (severe allergic reaction) | 183 | 36.8 32.1–42.3ROR 40.7 · χ² 6,342 / p <1e-300 | 36.6 EB05 32.4 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 33.9 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 203 | 34.0 29.8–38.7ROR 37.9 · χ² 6,466 / p <1e-300 | 33.8 EB05 30.1 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 34.3 | no trial data cached |
| Flushing | 228 | 24.7 21.8–27.9ROR 27.9 · χ² 5,167 / p <1e-300 | 24.6 EB05 22.0 · IC025 +4.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 38.9 | no trial data cached |
| Chest discomfort | 173 | 18.7 16.2–21.6ROR 20.5 · χ² 2,895 / p <1e-300 | 18.7 EB05 16.4 · IC025 +3.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 16.2 | no trial data cached |
| Cyanosis (blue skin from low oxygen) | 26 | 18.2 12.4–26.7ROR 18.5 · χ² 406 / p 2e-90 | 17.9 EB05 12.7 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 18.0 · 92% clinician | no trial data cached |
| Throat tightness | 40 | 16.3 12.0–22.2ROR 16.7 · χ² 561 / p 3e-124 | 16.1 EB05 12.3 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 15.9 | no trial data cached |
| Oxygen saturation decreased | 71 | 14.0 11.2–17.6ROR 14.5 · χ² 848 / p 9e-187 | 13.9 EB05 11.3 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious PRR 12.8 | no trial data cached |
| Cardio-respiratory arrest | 53 | 13.9 10.7–18.1ROR 14.3 · χ² 622 / p 1e-137 | 13.7 EB05 10.8 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 12.8 · ♀ 46% (drug 70%) · 94% clinician | no trial data cached |
| Pallor | 34 | 13.8 9.9–19.2ROR 14.0 · χ² 390 / p 5e-87 | 13.4 EB05 9.8 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 15.3 · 97% clinician | no trial data cached |
| Hypotension (low blood pressure) | 205 | 11.3 9.9–12.9ROR 12.5 · χ² 1,930 / p <1e-300 | 11.2 EB05 10.0 · IC025 +3.2 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 10.8 · ♀ 48% (drug 70%) | no trial data cached |
| Adverse reaction | 13 | 10.8 6.3–18.6ROR 10.9 · χ² 106 / p 3e-25 | 9.2 EB05 5.3 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious n=3 | no trial data cached |
| Bronchospasm (airway tightening) | 13 | 10.0 5.8–17.2ROR 10.1 · χ² 97 / p 4e-23 | 8.4 EB05 4.9 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.2 | no trial data cached |
| Back pain | 210 | 10.0 8.8–11.3ROR 11.1 · χ² 1,703 / p <1e-300 | 9.9 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.8 | no trial data cached |
| Infusion site pain | 11 | 9.5 5.3–17.1ROR 9.6 · χ² 75 / p 2e-18 | 7.6 EB05 4.3 · IC025 +1.8 3/3 methods agree | Labeled (related wording) related wording | serious n=4 | no trial data cached |
| Hyperhidrosis (excessive sweating) | 108 | 9.2 7.7–11.1ROR 9.7 · χ² 790 / p 5e-174 | 9.0 EB05 7.7 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.6 | no trial data cached |
| Feeling hot | 51 | 9.2 7.0–12.0ROR 9.4 · χ² 364 / p 2e-81 | 8.8 EB05 6.8 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 13.2 · 91% clinician | no trial data cached |
| Blood pressure decreased | 55 | 9.1 7.1–11.9ROR 9.4 · χ² 392 / p 1e-87 | 8.8 EB05 6.9 · IC025 +2.6 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 9.7 · ♀ 47% (drug 70%) | no trial data cached |
| Wheezing | 49 | 9.1 6.9–12.0ROR 9.4 · χ² 348 / p 7e-78 | 8.7 EB05 6.8 · IC025 +2.6 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 10.1 | no trial data cached |
| Respiratory arrest | 23 | 9.1 6.1–13.7ROR 9.2 · χ² 158 / p 1e-36 | 8.2 EB05 5.6 · IC025 +2.3 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 8.2 · ♀ 41% (drug 70%) · 96% clinician | no trial data cached |
| Dyspnoea (shortness of breath) | 462 | 9.0 8.3–9.8ROR 11.6 · χ² 3,371 / p <1e-300 | 9.0 EB05 8.3 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.2 | no trial data cached |
| Urinary incontinence | 24 | 8.9 6.0–13.3ROR 9.0 · χ² 162 / p 3e-37 | 8.1 EB05 5.5 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 11.2 · 91% clinician | no trial data cached |
| Hypersensitivity (allergic reaction) | 150 | 8.9 7.7–10.4ROR 9.6 · χ² 1,057 / p 4e-232 | 8.8 EB05 7.6 · IC025 +2.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 9.6 | no trial data cached |
| Blood pressure systolic increased | 15 | 8.4 5.1–14.0ROR 8.5 · χ² 91 / p 7e-22 | 7.1 EB05 4.4 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious PRR 8.6 | no trial data cached |
| Paraesthesia oral | 11 | 8.4 4.7–15.2ROR 8.5 · χ² 65 / p 4e-16 | 6.7 EB05 3.9 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 10.2 | no trial data cached |
| Throat irritation | 34 | 8.4 6.0–11.7ROR 8.5 · χ² 214 / p 8e-49 | 7.8 EB05 5.7 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 11.8 · ♀ 90% (drug 70%) · 91% clinician | no trial data cached |
| Sneezing | 17 | 8.4 5.2–13.5ROR 8.5 · χ² 103 / p 1e-24 | 7.2 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 11.5 | no trial data cached |
| Chest pain | 137 | 8.1 6.9–9.6ROR 8.7 · χ² 858 / p 6e-189 | 8.0 EB05 6.9 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.6 · 91% clinician | no trial data cached |
| Retching | 15 | 7.8 4.7–12.9ROR 7.8 · χ² 82 / p 7e-20 | 6.6 EB05 4.1 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 14.3 | no trial data cached |
| Skin discolouration | 29 | 7.0 4.9–10.0ROR 7.1 · χ² 142 / p 4e-33 | 6.4 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 | no trial data cached |
| Anaphylactic shock | 16 | 6.9 4.2–11.2ROR 6.9 · χ² 75 / p 3e-18 | 5.9 EB05 3.8 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.1 | no trial data cached |
| Cold sweat | 11 | 6.9 3.8–12.4ROR 6.9 · χ² 50 / p 1e-12 | 5.5 EB05 3.3 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Loss of consciousness | 69 | 5.9 4.7–7.5ROR 6.1 · χ² 280 / p 4e-63 | 5.7 EB05 4.7 · IC025 +2.1 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.6 | no trial data cached |
| Presyncope (near-fainting) | 13 | 5.9 3.4–10.2ROR 6.0 · χ² 48 / p 2e-12 | 5.0 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 6.5 | no trial data cached |
| Chills | 62 | 5.8 4.6–7.4ROR 6.0 · χ² 244 / p 2e-55 | 5.6 EB05 4.5 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.5 | no trial data cached |
| Cardiac arrest (heart stopping) | 42 | 5.6 4.1–7.5ROR 5.7 · χ² 154 / p 1e-35 | 5.3 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.2 · ♀ 42% (drug 70%) · 95% clinician | no trial data cached |
| Blood pressure increased | 71 | 5.1 4.1–6.4ROR 5.3 · χ² 232 / p 1e-52 | 5.0 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.2 | no trial data cached |
| Syncope (fainting) | 46 | 5.1 3.8–6.7ROR 5.2 · χ² 147 / p 4e-34 | 4.8 EB05 3.8 · IC025 +1.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.8 · 90% clinician | no trial data cached |
| Feeling cold | 12 | 4.7 2.7–8.3ROR 4.8 · χ² 32 / p 8e-9 | 4.1 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.8 | no trial data cached |
| Lip swelling | 14 | 4.6 2.8–7.8ROR 4.7 · χ² 37 / p 7e-10 | 4.1 EB05 2.6 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.0 | 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 |
|---|---|---|---|---|---|---|
| Dyspnoea (shortness of breath) | 462 | 9.0 8.3–9.8ROR 11.6 · χ² 3,371 / p <1e-300 | 9.0 EB05 8.3 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.2 | no trial data cached |
| Flushing | 228 | 24.7 21.8–27.9ROR 27.9 · χ² 5,167 / p <1e-300 | 24.6 EB05 22.0 · IC025 +4.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 38.9 | no trial data cached |
| Back pain | 210 | 10.0 8.8–11.3ROR 11.1 · χ² 1,703 / p <1e-300 | 9.9 EB05 8.8 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.8 | no trial data cached |
| Hypotension (low blood pressure) | 205 | 11.3 9.9–12.9ROR 12.5 · χ² 1,930 / p <1e-300 | 11.2 EB05 10.0 · IC025 +3.2 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 10.8 · ♀ 48% (drug 70%) | no trial data cached |
| Infusion related reaction (reaction during infusion) | 203 | 34.0 29.8–38.7ROR 37.9 · χ² 6,466 / p <1e-300 | 33.8 EB05 30.1 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 34.3 | no trial data cached |
| Anaphylactic reaction (severe allergic reaction) | 183 | 36.8 32.1–42.3ROR 40.7 · χ² 6,342 / p <1e-300 | 36.6 EB05 32.4 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 33.9 | no trial data cached |
| Chest discomfort | 173 | 18.7 16.2–21.6ROR 20.5 · χ² 2,895 / p <1e-300 | 18.7 EB05 16.4 · IC025 +3.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 16.2 | no trial data cached |
| Hypersensitivity (allergic reaction) | 150 | 8.9 7.7–10.4ROR 9.6 · χ² 1,057 / p 4e-232 | 8.8 EB05 7.6 · IC025 +2.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 9.6 | no trial data cached |
| Unresponsive to stimuli | 139 | 59.9 51.0–70.3ROR 64.5 · χ² 7,956 / p <1e-300 | 59.1 EB05 51.3 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious PRR 56.9 · 92% clinician | no trial data cached |
| Chest pain | 137 | 8.1 6.9–9.6ROR 8.7 · χ² 858 / p 6e-189 | 8.0 EB05 6.9 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.6 · 91% clinician | no trial data cached |
| Hyperhidrosis (excessive sweating) | 108 | 9.2 7.7–11.1ROR 9.7 · χ² 790 / p 5e-174 | 9.0 EB05 7.7 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.6 | no trial data cached |
| Erythema (skin redness) | 79 | 4.2 3.4–5.3ROR 4.4 · χ² 194 / p 2e-44 | 4.1 EB05 3.4 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Blood pressure increased | 71 | 5.1 4.1–6.4ROR 5.3 · χ² 232 / p 1e-52 | 5.0 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.2 | no trial data cached |
| Oxygen saturation decreased | 71 | 14.0 11.2–17.6ROR 14.5 · χ² 848 / p 9e-187 | 13.9 EB05 11.3 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious PRR 12.8 | no trial data cached |
| Loss of consciousness | 69 | 5.9 4.7–7.5ROR 6.1 · χ² 280 / p 4e-63 | 5.7 EB05 4.7 · IC025 +2.1 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 5.6 | 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.
- Unresponsive to stimuli — n=139, PRR 59.9
- Infusion related reaction — n=203, PRR 34.0
- Throat tightness — n=40, PRR 16.3
- Cardio-respiratory arrest — n=53, PRR 13.9
- Pallor — n=34, PRR 13.8
- Hyperhidrosis — n=108, PRR 9.2
- Feeling hot — n=51, PRR 9.2
- Urinary incontinence — n=24, PRR 8.9
- Throat irritation — n=34, PRR 8.4
- Skin discolouration — n=29, PRR 7.0
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 Ferumoxytol?
In FDA FAERS, the most frequently co-reported reaction terms for Ferumoxytol are dyspnoea, flushing, back pain, hypotension, infusion related reaction, anaphylactic reaction. 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 Ferumoxytol have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: RISK FOR SERIOUS HYPERSENSITIVITY/ANAPHYLAXIS REACTIONS Fatal and serious hypersensitivity reactions including anaphylaxis have occurred in patients receiving ferumoxytol. Initial symptoms may include hypotension, syncope, unresponsiveness, cardiac/cardiorespiratory arrest.
Do FAERS signals prove that Ferumoxytol 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 cf94c7fc-13a0-4ac9-bb85-9c38aa704d35, effective 20260814; matched on
openfda.generic_name.exact:"FERUMOXYTOL") - 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, 54 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.