Pegloticase side effects: what 3,686 FDA adverse event reports show
Drug class
Uric Acid-specific Enzyme
Brand names
Krystexxa
Who reports
3,686 reports · 47% serious · 123 with death outcome · 20% female
Used for
KRYSTEXXA ® (pegloticase) is indicated, for the treatment of chronic gout in adult patients refractory to conventional therapy. Gout refractory to conventional therapy occurs in patients who have failed to normalize serum uric acid and whose signs and symptoms are inadequately controlled with xanthine oxidase inhibitors at the maximum medically appropriate dose or for whom these drugs are contraindicated.
What it is
Pegloticase is a uric acid specific enzyme which is a PEGylated product that consists of recombinant modified mammalian urate oxidase (uricase) produced by a genetically modified strain of Escherichia coli. Uricase is covalently conjugated to monomethoxypoly (ethylene glycol) [mPEG] (10 kDa molecular weight).
Boxed warning
ANAPHYLAXIS and INFUSION REACTIONS, G6PD DEFICIENCY ASSOCIATED HEMOLYSIS and METHEMOGLOBINEMIA Anaphylaxis and infusion reactions have been reported to occur during and after administration of KRYSTEXXA. ( 5.1 , 5.2 ) Anaphylaxis may occur with any infusion, and generally manifests within 2 hours of the infusion.
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. 21 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 |
|---|---|---|---|---|---|---|
| Gout | 562 | 183.7 170.0–198.6ROR 216.6 · χ² 98,810 / p <1e-300 | 176.9 EB05 164.9 · IC025 +7.1 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 129.7 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 365 | 31.6 28.7–34.8ROR 35.0 · χ² 10,760 / p <1e-300 | 31.4 EB05 28.8 · IC025 +4.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 28.5 | no trial data cached |
| Therapeutic response decreased | 240 | 22.7 20.1–25.7ROR 24.2 · χ² 4,957 / p <1e-300 | 22.6 EB05 20.3 · IC025 +4.2 3/3 methods agree | Reporting / coding artifact | serious PRR 24.9 | no trial data cached |
| Anaphylactic reaction (severe allergic reaction) | 102 | 10.6 8.7–12.8ROR 10.9 · χ² 876 / p 8e-193 | 10.4 EB05 8.8 · IC025 +3.0 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 13.0 | no trial data cached |
| Throat tightness | 36 | 7.6 5.5–10.5ROR 7.7 · χ² 199 / p 1e-45 | 7.0 EB05 5.3 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 | no trial data cached |
| Glomerular filtration rate decreased | 14 | 6.6 3.9–11.1ROR 6.6 · χ² 61 / p 3e-15 | 5.5 EB05 3.5 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 7.1 | no trial data cached |
| Pharyngeal swelling | 11 | 6.5 3.6–11.8ROR 6.6 · χ² 46 / p 5e-12 | 5.3 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious n=7 | no trial data cached |
| Unresponsive to stimuli | 27 | 6.0 4.1–8.7ROR 6.0 · χ² 107 / p 2e-25 | 5.5 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.4 | no trial data cached |
| Circumstance or information capable of leading to medication error | 33 | 5.6 4.0–7.9ROR 5.6 · χ² 120 / p 3e-28 | 5.2 EB05 3.9 · IC025 +1.8 3/3 methods agree | Labeled (related wording) related wording | serious n=1 | no trial data cached |
| Chest discomfort | 100 | 5.6 4.6–6.8ROR 5.7 · χ² 373 / p 2e-83 | 5.4 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.7 | no trial data cached |
| Blood pressure decreased | 65 | 5.6 4.4–7.1ROR 5.7 · χ² 240 / p 2e-54 | 5.4 EB05 4.4 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.3 | no trial data cached |
| Urticaria (hives) | 144 | 4.9 4.2–5.8ROR 5.1 · χ² 450 / p 4e-100 | 4.8 EB05 4.2 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.2 | no trial data cached |
| Dialysis | 12 | 4.8 2.7–8.5ROR 4.8 · χ² 32 / p 6e-9 | 4.1 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 | no trial data cached |
| Flushing | 83 | 4.6 3.7–5.7ROR 4.7 · χ² 233 / p 6e-53 | 4.5 EB05 3.8 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 8.3 | no trial data cached |
| Hypoaesthesia oral | 11 | 4.2 2.3–7.5ROR 4.2 · χ² 23 / p 7e-7 | 3.6 EB05 2.2 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 | no trial data cached |
| Therapy partial responder | 11 | 4.2 2.3–7.5ROR 4.2 · χ² 23 / p 7e-7 | 3.6 EB05 2.2 · IC025 +0.8 3/3 methods agree | Reporting / coding artifact | serious PRR 0.6 | no trial data cached |
| Gait inability | 24 | 4.1 2.8–6.1ROR 4.1 · χ² 54 / p 1e-13 | 3.8 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 · 71% consumer | no trial data cached |
| Cold sweat | 12 | 3.9 2.2–6.8ROR 3.9 · χ² 23 / p 9e-7 | 3.4 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Osteomyelitis | 12 | 3.8 2.1–6.6ROR 3.8 · χ² 22 / p 2e-6 | 3.4 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Therapy non-responder | 28 | 3.6 2.5–5.2ROR 3.6 · χ² 49 / p 1e-12 | 3.4 EB05 2.5 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 1.5 | no trial data cached |
| Loss of consciousness | 80 | 3.6 2.9–4.4ROR 3.6 · χ² 145 / p 1e-33 | 3.5 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Chest pain | 115 | 3.5 2.9–4.2ROR 3.6 · χ² 207 / p 3e-47 | 3.5 EB05 3.0 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Blood potassium increased | 10 | 3.5 1.9–6.5ROR 3.5 · χ² 16 / p 4e-5 | 3.1 EB05 1.8 · IC025 +0.6 | Lab value / disease marker | serious PRR 5.5 | no trial data cached |
| Feeling hot | 37 | 3.4 2.5–4.7ROR 3.5 · χ² 61 / p 2e-15 | 3.3 EB05 2.5 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 | no trial data cached |
| Product storage error | 52 | 3.4 2.6–4.5ROR 3.5 · χ² 87 / p 6e-21 | 3.3 EB05 2.6 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | – | no trial data cached |
| Blood pressure increased | 91 | 3.4 2.8–4.1ROR 3.4 · χ² 151 / p 5e-35 | 3.3 EB05 2.8 · IC025 +1.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.1 | no trial data cached |
| Chromaturia | 13 | 3.3 1.9–5.6ROR 3.3 · χ² 18 / p 9e-6 | 3.0 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
| Hyperhidrosis (excessive sweating) | 71 | 3.1 2.5–3.9ROR 3.2 · χ² 102 / p 3e-24 | 3.1 EB05 2.5 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Contraindicated product administered | 16 | 3.0 1.9–4.9ROR 3.0 · χ² 20 / p 5e-6 | 2.8 EB05 1.9 · IC025 +0.7 | Reporting / coding artifact | serious PRR 4.0 | no trial data cached |
| Swollen tongue | 16 | 2.9 1.8–4.7ROR 2.9 · χ² 18 / p 1e-5 | 2.7 EB05 1.8 · IC025 +0.6 | Not in label — unassessed | serious PRR 4.0 | no trial data cached |
| Presyncope (near-fainting) | 12 | 2.8 1.6–5.0ROR 2.8 · χ² 12 / p 2e-4 | 2.6 EB05 1.6 · IC025 +0.4 | Not in label — unassessed | serious PRR 3.7 | no trial data cached |
| Throat irritation | 22 | 2.8 1.8–4.2ROR 2.8 · χ² 24 / p 6e-7 | 2.7 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Lip swelling | 16 | 2.7 1.7–4.5ROR 2.7 · χ² 16 / p 3e-5 | 2.6 EB05 1.7 · IC025 +0.5 | Labeled (related wording) related wording | serious PRR 3.0 | no trial data cached |
| Inappropriate schedule of product administration | 85 | 2.7 2.2–3.4ROR 2.8 · χ² 93 / p 3e-22 | 2.7 EB05 2.3 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 4.4 | no trial data cached |
| Peripheral swelling | 73 | 2.7 2.2–3.4ROR 2.7 · χ² 77 / p 7e-19 | 2.7 EB05 2.2 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.5 · 71% consumer | no trial data cached |
| Therapeutic product effect decreased | 21 | 2.7 1.8–4.1ROR 2.7 · χ² 21 / p 3e-6 | 2.6 EB05 1.8 · IC025 +0.6 | Reporting / coding artifact | serious PRR 1.5 | no trial data cached |
| Cardiac failure congestive | 36 | 2.5 1.8–3.5ROR 2.5 · χ² 32 / p 9e-9 | 2.5 EB05 1.9 · IC025 +0.8 | Labeled (related wording) related wording | serious PRR 2.9 | no trial data cached |
| Intentional dose omission | 12 | 2.5 1.4–4.4ROR 2.5 · χ² 9 / p 0.001 | 2.4 EB05 1.5 · IC025 +0.3 | Reporting / coding artifact | serious PRR 3.1 | no trial data cached |
| Localised infection | 10 | 2.4 1.3–4.4ROR 2.4 · χ² 6 / p 0.005 | 2.2 EB05 1.3 · IC025 +0.1 | Not in label — unassessed | serious PRR 3.0 | no trial data cached |
| Therapy interrupted | 28 | 2.3 1.6–3.3ROR 2.3 · χ² 20 / p 5e-6 | 2.3 EB05 1.6 · IC025 +0.5 | Reporting / coding artifact | serious PRR 1.1 | 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 |
|---|---|---|---|---|---|---|
| Gout | 562 | 183.7 170.0–198.6ROR 216.6 · χ² 98,810 / p <1e-300 | 176.9 EB05 164.9 · IC025 +7.1 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 129.7 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 365 | 31.6 28.7–34.8ROR 35.0 · χ² 10,760 / p <1e-300 | 31.4 EB05 28.8 · IC025 +4.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 28.5 | no trial data cached |
| Therapeutic response decreased | 240 | 22.7 20.1–25.7ROR 24.2 · χ² 4,957 / p <1e-300 | 22.6 EB05 20.3 · IC025 +4.2 3/3 methods agree | Reporting / coding artifact | serious PRR 24.9 | no trial data cached |
| Urticaria (hives) | 144 | 4.9 4.2–5.8ROR 5.1 · χ² 450 / p 4e-100 | 4.8 EB05 4.2 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.2 | no trial data cached |
| Chest pain | 115 | 3.5 2.9–4.2ROR 3.6 · χ² 207 / p 3e-47 | 3.5 EB05 3.0 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Anaphylactic reaction (severe allergic reaction) | 102 | 10.6 8.7–12.8ROR 10.9 · χ² 876 / p 8e-193 | 10.4 EB05 8.8 · IC025 +3.0 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 13.0 | no trial data cached |
| Chest discomfort | 100 | 5.6 4.6–6.8ROR 5.7 · χ² 373 / p 2e-83 | 5.4 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.7 | no trial data cached |
| Blood pressure increased | 91 | 3.4 2.8–4.1ROR 3.4 · χ² 151 / p 5e-35 | 3.3 EB05 2.8 · IC025 +1.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.1 | no trial data cached |
| Inappropriate schedule of product administration | 85 | 2.7 2.2–3.4ROR 2.8 · χ² 93 / p 3e-22 | 2.7 EB05 2.3 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 4.4 | no trial data cached |
| Flushing | 83 | 4.6 3.7–5.7ROR 4.7 · χ² 233 / p 6e-53 | 4.5 EB05 3.8 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 8.3 | no trial data cached |
| Loss of consciousness | 80 | 3.6 2.9–4.4ROR 3.6 · χ² 145 / p 1e-33 | 3.5 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Peripheral swelling | 73 | 2.7 2.2–3.4ROR 2.7 · χ² 77 / p 7e-19 | 2.7 EB05 2.2 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.5 · 71% consumer | no trial data cached |
| Hyperhidrosis (excessive sweating) | 71 | 3.1 2.5–3.9ROR 3.2 · χ² 102 / p 3e-24 | 3.1 EB05 2.5 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Blood glucose increased | 66 | 2.0 1.6–2.5ROR 2.0 · χ² 32 / p 1e-8 | 2.0 EB05 1.6 · IC025 +0.6 | Labeled (related wording) related wording | serious PRR 5.0 · 74% consumer | no trial data cached |
| Blood pressure decreased | 65 | 5.6 4.4–7.1ROR 5.7 · χ² 240 / p 2e-54 | 5.4 EB05 4.4 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.3 | 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.
- Throat tightness — n=36, PRR 7.6
- Unresponsive to stimuli — n=27, PRR 6.0
- Flushing — n=83, PRR 4.6
- Gait inability — n=24, PRR 4.1
- Loss of consciousness — n=80, PRR 3.6
- Feeling hot — n=37, PRR 3.4
- Hyperhidrosis — n=71, PRR 3.1
- Throat irritation — n=22, PRR 2.8
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 Pegloticase?
In FDA FAERS, the most frequently co-reported reaction terms for Pegloticase are gout, infusion related reaction, urticaria, chest pain, anaphylactic reaction, chest discomfort. 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 Pegloticase have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: ANAPHYLAXIS and INFUSION REACTIONS, G6PD DEFICIENCY ASSOCIATED HEMOLYSIS and METHEMOGLOBINEMIA Anaphylaxis and infusion reactions have been reported to occur during and after administration of KRYSTEXXA. ( 5.1 , 5.2 ) Anaphylaxis may occur with any infusion, and generally manifests within 2 hours of the infusion.
Do FAERS signals prove that Pegloticase 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 6e566303-d93a-4130-b764-25749829aa95, effective 20260709; matched on
openfda.generic_name.exact:"PEGLOTICASE") - 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, 61 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.