Rasburicase side effects: what 2,410 FDA adverse event reports show

Rasburicase · Elitek · 109 reaction terms · 2,840 drug–reaction co-reports · data 2026-09-14

Drug class

Recombinant urate-oxidase

FDA label, Indications wording

Brand names

Elitek

openFDA label

Who reports

2,410 reports · 91% serious · 659 with death outcome · 36% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Elitek is indicated for the initial management of plasma uric acid levels in pediatric and adult patients with leukemia, lymphoma, and solid tumor malignancies who are receiving anticancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid.

FDA label, Indications and Usage

What it is

Elitek (rasburicase) is a recombinant urate-oxidase produced by a genetically modified Saccharomyces cerevisiae strain. The cDNA coding for rasburicase was cloned from a strain of Aspergillus flavus. Rasburicase is a tetrameric protein with identical subunits.

FDA label, Description section

Boxed warning

HYPERSENSITIVITY REACTIONS, HEMOLYSIS, METHEMOGLOBINEMIA, AND INTERFERENCE WITH URIC ACID MEASUREMENTS WARNING: HYPERSENSITIVITY REACTIONS, HEMOLYSIS, METHEMOGLOBINEMIA, AND INTERFERENCE WITH URIC ACID MEASUREMENTS See full prescribing information for complete boxed warning .

FDA label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Labeled — boxed warning 1Labeled adverse reaction 2Labeled (related wording) 1Likely indication confounding 2Lab value / disease marker 2Not in label — unassessed 32

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.
Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
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. 69 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Cytokine release syndrome	128	58.8 49.7–69.7ROR 62.1 · χ² 7,177 / p <1e-300	58.0 EB05 50.0 · IC025 +5.3 3/3 methods agree	Not in label — unassessed	serious PRR 36.9 · 98% clinician	no trial data cached
Multiple organ dysfunction syndrome	87	27.2 22.1–33.5ROR 28.2 · χ² 2,166 / p <1e-300	27.0 EB05 22.6 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious PRR 17.2 · 98% clinician	no trial data cached
Febrile neutropenia	202	26.6 23.3–30.4ROR 29.0 · χ² 4,955 / p <1e-300	26.5 EB05 23.6 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 16.9 · 97% clinician	no trial data cached
Hyperbilirubinaemia	30	25.4 17.8–36.3ROR 25.7 · χ² 677 / p 1e-149	25.0 EB05 18.3 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 15.3 · ♀ 4% (drug 36%) · 97% clinician	no trial data cached
Disseminated intravascular coagulation	38	23.5 17.1–32.2ROR 23.8 · χ² 794 / p 6e-175	23.2 EB05 17.6 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 14.9 · 95% clinician	no trial data cached
Hypercalcaemia	23	16.3 10.8–24.4ROR 16.4 · χ² 314 / p 2e-70	15.8 EB05 10.8 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 11.0 · 96% clinician	no trial data cached
Toxic epidermal necrolysis (severe skin peeling reaction)	26	15.0 10.2–22.0ROR 15.2 · χ² 326 / p 3e-73	14.6 EB05 10.2 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 9.5 · 96% clinician	no trial data cached
Hepatocellular injury	24	14.7 9.9–21.9ROR 14.8 · χ² 293 / p 6e-66	14.2 EB05 9.7 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 9.3 · 96% clinician	no trial data cached
Hyperkalaemia (high potassium)	57	14.2 11.0–18.4ROR 14.6 · χ² 688 / p 6e-152	14.1 EB05 11.2 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 9.2 · 91% clinician	no trial data cached
Blood lactate dehydrogenase increased	26	14.2 9.7–20.8ROR 14.4 · χ² 306 / p 9e-69	13.8 EB05 9.6 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious PRR 9.6 · 96% clinician	no trial data cached
Ventricular fibrillation	18	14.1 8.9–22.3ROR 14.2 · χ² 206 / p 6e-47	13.3 EB05 8.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.9	no trial data cached
Lymphopenia	21	13.0 8.5–19.9ROR 13.1 · χ² 221 / p 3e-50	12.3 EB05 8.0 · IC025 +2.6 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 8.9 · 90% clinician	no trial data cached
Hypoxia (low oxygen)	52	12.9 9.9–16.9ROR 13.2 · χ² 560 / p 4e-124	12.7 EB05 9.9 · IC025 +3.1 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 8.3 · 92% clinician	no trial data cached
Neurotoxicity	25	12.5 8.5–18.5ROR 12.7 · χ² 254 / p 2e-57	11.9 EB05 8.1 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 8.0 · 96% clinician	no trial data cached
Blood potassium increased	23	12.3 8.2–18.6ROR 12.5 · χ² 229 / p 6e-52	11.6 EB05 7.8 · IC025 +2.6 3/3 methods agree	Lab value / disease marker	serious PRR 9.3 · ♀ 67% (drug 36%) · 100% clinician	no trial data cached
Acute myeloid leukaemia	21	11.7 7.7–18.0ROR 11.8 · χ² 196 / p 9e-45	10.9 EB05 7.1 · IC025 +2.5 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 7.5 · 100% clinician	no trial data cached
Respiratory failure	91	10.9 8.9–13.3ROR 11.2 · χ² 807 / p 9e-178	10.7 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.8 · 94% clinician	no trial data cached
Mucosal inflammation	32	10.7 7.6–15.1ROR 10.8 · χ² 272 / p 3e-61	10.1 EB05 7.3 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 7.2 · 91% clinician	no trial data cached
Bacteraemia	14	10.4 6.1–17.5ROR 10.4 · χ² 109 / p 8e-26	8.9 EB05 5.2 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 6.6	no trial data cached
Toxic skin eruption	12	10.3 5.9–18.2ROR 10.4 · χ² 92 / p 4e-22	8.6 EB05 4.8 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 7.1	no trial data cached
Haematotoxicity	11	10.3 5.7–18.6ROR 10.4 · χ² 84 / p 3e-20	8.4 EB05 4.6 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.7	no trial data cached
Encephalopathy	29	10.3 7.2–14.8ROR 10.4 · χ² 235 / p 3e-53	9.6 EB05 6.8 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 6.6 · ♀ 59% (drug 36%) · 100% clinician	no trial data cached
Posterior reversible encephalopathy syndrome	11	10.1 5.6–18.2ROR 10.1 · χ² 81 / p 1e-19	8.2 EB05 4.5 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 6.4	no trial data cached
Septic shock	49	9.9 7.5–13.0ROR 10.1 · χ² 382 / p 2e-85	9.5 EB05 7.3 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 6.1 · 92% clinician	no trial data cached
Clostridium difficile colitis	12	9.8 5.6–17.3ROR 9.9 · χ² 87 / p 7e-21	8.1 EB05 4.6 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.4	no trial data cached
Cytopenia	13	9.5 5.5–16.3ROR 9.5 · χ² 90 / p 1e-21	7.9 EB05 4.6 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.2	no trial data cached
Pancytopenia (all blood cells low)	60	9.4 7.3–12.0ROR 9.6 · χ² 441 / p 3e-98	9.0 EB05 7.2 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.9 · 93% clinician	no trial data cached
Cardiogenic shock	15	9.2 5.5–15.2ROR 9.2 · χ² 101 / p 5e-24	7.8 EB05 4.8 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.8	no trial data cached
Multi-organ failure	18	8.9 5.6–14.2ROR 9.0 · χ² 119 / p 5e-28	7.8 EB05 5.0 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 5.4	no trial data cached
Candida infection (yeast infection)	17	8.9 5.5–14.3ROR 8.9 · χ² 111 / p 3e-26	7.7 EB05 4.9 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.1	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	132	8.5 7.2–10.0ROR 8.9 · χ² 869 / p 3e-191	8.3 EB05 7.2 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 5.5 · 96% clinician	no trial data cached
Electrolyte imbalance	11	8.3 4.6–15.0ROR 8.4 · χ² 64 / p 7e-16	6.6 EB05 3.8 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 5.5	no trial data cached
Acute kidney injury (sudden kidney damage)	142	8.1 6.9–9.5ROR 8.6 · χ² 885 / p 1e-194	8.0 EB05 6.9 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.2 · 98% clinician	no trial data cached
Sinus tachycardia	13	8.0 4.6–13.7ROR 8.0 · χ² 73 / p 8e-18	6.6 EB05 4.0 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.2	no trial data cached
Sepsis (blood infection)	102	8.0 6.6–9.6ROR 8.3 · χ² 616 / p 2e-136	7.7 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.1 · 98% clinician	no trial data cached
Hypocalcaemia (low calcium)	16	7.4 4.5–12.0ROR 7.4 · χ² 82 / p 7e-20	6.3 EB05 4.0 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 5.0	no trial data cached
Subdural haematoma	12	7.3 4.1–12.8ROR 7.3 · χ² 59 / p 9e-15	5.9 EB05 3.5 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.6	no trial data cached
Respiratory distress	23	7.3 4.8–10.9ROR 7.3 · χ² 118 / p 9e-28	6.5 EB05 4.5 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 4.7 · 100% clinician	no trial data cached
Hepatic failure	25	7.2 4.9–10.6ROR 7.3 · χ² 127 / p 7e-30	6.5 EB05 4.6 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 4.4 · ♀ 58% (drug 36%) · 100% clinician	no trial data cached
Hepatotoxicity (liver damage)	18	7.1 4.5–11.2ROR 7.1 · χ² 88 / p 4e-21	6.1 EB05 4.1 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.6	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

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
Febrile neutropenia	202	26.6 23.3–30.4ROR 29.0 · χ² 4,955 / p <1e-300	26.5 EB05 23.6 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 16.9 · 97% clinician	no trial data cached
Acute kidney injury (sudden kidney damage)	142	8.1 6.9–9.5ROR 8.6 · χ² 885 / p 1e-194	8.0 EB05 6.9 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.2 · 98% clinician	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	132	8.5 7.2–10.0ROR 8.9 · χ² 869 / p 3e-191	8.3 EB05 7.2 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 5.5 · 96% clinician	no trial data cached
Cytokine release syndrome	128	58.8 49.7–69.7ROR 62.1 · χ² 7,177 / p <1e-300	58.0 EB05 50.0 · IC025 +5.3 3/3 methods agree	Not in label — unassessed	serious PRR 36.9 · 98% clinician	no trial data cached
Sepsis (blood infection)	102	8.0 6.6–9.6ROR 8.3 · χ² 616 / p 2e-136	7.7 EB05 6.5 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.1 · 98% clinician	no trial data cached
Respiratory failure	91	10.9 8.9–13.3ROR 11.2 · χ² 807 / p 9e-178	10.7 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.8 · 94% clinician	no trial data cached
Multiple organ dysfunction syndrome	87	27.2 22.1–33.5ROR 28.2 · χ² 2,166 / p <1e-300	27.0 EB05 22.6 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious PRR 17.2 · 98% clinician	no trial data cached
Thrombocytopenia (low platelets)	79	6.2 5.0–7.7ROR 6.3 · χ² 338 / p 7e-76	6.0 EB05 4.9 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 4.0 · 92% clinician	no trial data cached
Renal failure (kidney failure)	77	5.0 4.0–6.2ROR 5.1 · χ² 245 / p 2e-55	4.9 EB05 4.0 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 3.2 · 96% clinician	no trial data cached
Pancytopenia (all blood cells low)	60	9.4 7.3–12.0ROR 9.6 · χ² 441 / p 3e-98	9.0 EB05 7.2 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.9 · 93% clinician	no trial data cached
Hyperkalaemia (high potassium)	57	14.2 11.0–18.4ROR 14.6 · χ² 688 / p 6e-152	14.1 EB05 11.2 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 9.2 · 91% clinician	no trial data cached
Disease progression	55	4.1 3.1–5.3ROR 4.1 · χ² 124 / p 3e-29	3.9 EB05 3.1 · IC025 +1.5 3/3 methods agree	Reporting / coding artifact	serious PRR 2.9 · 98% clinician	no trial data cached
White blood cell count decreased	53	4.3 3.3–5.5ROR 4.3 · χ² 129 / p 3e-30	4.1 EB05 3.3 · IC025 +1.6 3/3 methods agree	Lab value / disease marker	serious PRR 3.8 · 91% clinician	no trial data cached
Blood creatinine increased	52	6.9 5.3–9.1ROR 7.1 · χ² 258 / p 2e-58	6.6 EB05 5.2 · IC025 +2.3 3/3 methods agree	Lab value / disease marker	serious PRR 5.1	no trial data cached
Hypoxia (low oxygen)	52	12.9 9.9–16.9ROR 13.2 · χ² 560 / p 4e-124	12.7 EB05 9.9 · IC025 +3.1 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 8.3 · 92% clinician	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.

Cytokine release syndrome — n=128, PRR 58.8
Multiple organ dysfunction syndrome — n=87, PRR 27.2
Febrile neutropenia — n=202, PRR 26.6
Hyperbilirubinaemia — n=30, PRR 25.4
Disseminated intravascular coagulation — n=38, PRR 23.5
Hypercalcaemia — n=23, PRR 16.3
Toxic epidermal necrolysis — n=26, PRR 15.0
Hepatocellular injury — n=24, PRR 14.7
Hyperkalaemia — n=57, PRR 14.2
Neurotoxicity — n=25, PRR 12.5

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 Rasburicase?

In FDA FAERS, the most frequently co-reported reaction terms for Rasburicase are febrile neutropenia, acute kidney injury, neutropenia, cytokine release syndrome, sepsis, respiratory failure. 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 Rasburicase have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: HYPERSENSITIVITY REACTIONS, HEMOLYSIS, METHEMOGLOBINEMIA, AND INTERFERENCE WITH URIC ACID MEASUREMENTS WARNING: HYPERSENSITIVITY REACTIONS, HEMOLYSIS, METHEMOGLOBINEMIA, AND INTERFERENCE WITH URIC ACID MEASUREMENTS See full prescribing information for complete boxed warning .

Do FAERS signals prove that Rasburicase 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 0ae10bc4-6b65-402f-9db5-2d7753054922, effective 20260730; matched on openfda.generic_name.exact:"RASBURICASE")
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, field patient.drug.openfda.generic_name.exact, 109 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.