Drug · FAERS side-effect profile with label screen
Bendamustine Hydrochloride side effects: what 8,443 FDA adverse event reports show
Drug class
Alkylating drug
FDA label, Indications wording of the closest related product
Label matched
Bendamustine Hydrochloride (Bendamustine Hydrochloride)
closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match
Who reports
8,443 reports · 92% serious · 1,603 with death outcome · 40% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Bendamustine Hydrochloride Injection is an alkylating drug indicated for treatment of adult patients with: • Chronic lymphocytic leukemia (CLL). Efficacy relative to first line therapies other than chlorambucil has not been established. ( 1.1 ) • Indolent B-cell non-Hodgkin lymphoma (NHL) that has progressed during or within six months of treatment with rituximab or a rituximab-containing regimen.
FDA label, Indications and Usage
What it is
Bendamustine hydrochloride is an alkylating agent.
FDA label, Description section
Boxed warning
None in the current 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 adverse reaction 4Labeled (related wording) 5Likely indication confounding 11Lab value / disease marker 2Not in label — unassessed 18
What the badges mean
- 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. 959 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Mantle cell lymphoma recurrent | 58 | 276.0 209.3–363.9ROR 277.4 · χ² 13,478 / p <1e-300 | 221.0 EB05 177.3 · IC025 +5.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=30 | no trial data cached |
| Infusion site phlebitis | 27 | 235.7 157.7–352.1ROR 236.2 · χ² 5,351 / p <1e-300 | 181.2 EB05 130.8 · IC025 +4.8 3/3 methods agree | Labeled (related wording) related wording | – | no trial data cached |
| Lymphoma transformation | 36 | 195.4 138.5–275.7ROR 196.0 · χ² 6,085 / p <1e-300 | 160.9 EB05 121.4 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=29 · 93% clinician | no trial data cached |
| Erythropoiesis abnormal | 25 | 157.3 104.5–236.8ROR 157.7 · χ² 3,419 / p <1e-300 | 130.2 EB05 92.8 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=23 | no trial data cached |
| Coronavirus pneumonia | 13 | 155.7 88.3–274.6ROR 155.9 · χ² 1,695 / p <1e-300 | 118.6 EB05 73.7 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Cytomegalovirus enterocolitis | 44 | 107.9 79.7–146.3ROR 108.3 · χ² 4,289 / p <1e-300 | 97.5 EB05 75.6 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=41 | no trial data cached |
| Follicular lymphoma | 47 | 102.7 76.6–137.7ROR 103.1 · χ² 4,373 / p <1e-300 | 93.4 EB05 73.1 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=46 · 98% clinician | no trial data cached |
| Injection site phlebitis | 12 | 94.3 52.8–168.6ROR 94.4 · χ² 964 / p 5e-212 | 78.7 EB05 48.0 · IC025 +3.3 3/3 methods agree | Labeled (related wording) related wording | – | no trial data cached |
| Cytomegalovirus chorioretinitis | 88 | 84.2 68.0–104.2ROR 84.8 · χ² 6,819 / p <1e-300 | 79.0 EB05 66.1 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious n=82 | no trial data cached |
| Breakthrough covid-19 | 10 | 79.0 41.9–148.8ROR 79.0 · χ² 663 / p 1e-146 | 66.4 EB05 38.6 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Vasogenic cerebral oedema | 28 | 72.6 49.8–105.9ROR 72.8 · χ² 1,830 / p <1e-300 | 66.7 EB05 48.4 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=28 · ♀ 100% (drug 40%) · 93% clinician | no trial data cached |
| Cd4 lymphocytes decreased | 81 | 68.6 55.0–85.6ROR 69.1 · χ² 5,129 / p <1e-300 | 65.1 EB05 54.0 · IC025 +5.2 3/3 methods agree | Lab value / disease marker | serious n=76 | no trial data cached |
| Diffuse large b-cell lymphoma recurrent | 77 | 65.5 52.2–82.1ROR 65.9 · χ² 4,649 / p <1e-300 | 62.2 EB05 51.4 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=76 · 95% clinician | no trial data cached |
| Humoral immune defect | 13 | 63.8 36.7–110.9ROR 63.9 · χ² 716 / p 6e-158 | 56.7 EB05 35.3 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Mantle cell lymphoma | 52 | 62.5 47.4–82.4ROR 62.8 · χ² 2,979 / p <1e-300 | 59.1 EB05 46.8 · IC025 +4.8 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=45 | no trial data cached |
| Cytomegalovirus test positive | 57 | 58.6 45.0–76.2ROR 58.8 · χ² 3,064 / p <1e-300 | 55.7 EB05 44.6 · IC025 +4.8 3/3 methods agree | Lab value / disease marker | serious n=56 | no trial data cached |
| Infusion site irritation | 38 | 55.5 40.2–76.6ROR 55.7 · χ² 1,919 / p <1e-300 | 52.5 EB05 39.9 · IC025 +4.5 3/3 methods agree | Labeled (related wording) related wording | – | no trial data cached |
| Therapy responder | 15 | 55.2 33.0–92.3ROR 55.3 · χ² 722 / p 2e-159 | 50.3 EB05 32.4 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| B-cell lymphoma recurrent | 14 | 46.7 27.5–79.3ROR 46.7 · χ² 566 / p 2e-125 | 43.0 EB05 27.2 · IC025 +3.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=12 | no trial data cached |
| Chronic lymphocytic leukaemia recurrent | 17 | 44.3 27.4–71.6ROR 44.3 · χ² 660 / p 9e-146 | 41.4 EB05 27.3 · IC025 +3.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=9 | no trial data cached |
| Encephalitis cytomegalovirus | 10 | 41.7 22.3–78.0ROR 41.7 · χ² 349 / p 4e-78 | 38.0 EB05 22.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Diffuse large b-cell lymphoma | 174 | 41.1 35.4–47.7ROR 41.7 · χ² 6,611 / p <1e-300 | 40.0 EB05 35.2 · IC025 +4.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 33.4 | no trial data cached |
| Post-acute covid-19 syndrome | 28 | 40.8 28.1–59.3ROR 40.9 · χ² 1,024 / p 6e-225 | 38.9 EB05 28.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=28 · 93% clinician | no trial data cached |
| Chronic lymphocytic leukaemia | 108 | 40.8 33.7–49.3ROR 41.2 · χ² 4,059 / p <1e-300 | 39.6 EB05 33.7 · IC025 +4.8 3/3 methods agree | Likely indication confounding term in indications | serious n=62 | no trial data cached |
| Extravasation | 93 | 40.5 33.0–49.7ROR 40.8 · χ² 3,459 / p <1e-300 | 39.3 EB05 33.0 · IC025 +4.7 3/3 methods agree | Labeled adverse reaction exact term | serious n=5 | no trial data cached |
| Metastases to bone marrow | 11 | 39.3 21.6–71.4ROR 39.4 · χ² 365 / p 1e-81 | 36.3 EB05 21.6 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Cerebral aspergillosis | 13 | 38.1 22.0–66.0ROR 38.1 · χ² 424 / p 2e-94 | 35.5 EB05 22.1 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Granuloma skin | 17 | 36.9 22.8–59.6ROR 36.9 · χ² 546 / p 4e-121 | 34.8 EB05 23.0 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Skin neoplasm excision | 16 | 36.8 22.4–60.4ROR 36.9 · χ² 511 / p 2e-113 | 34.7 EB05 22.7 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Hypogammaglobulinaemia | 127 | 35.6 29.9–42.4ROR 35.9 · χ² 4,149 / p <1e-300 | 34.7 EB05 29.9 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=116 | no trial data cached |
| Pneumonia cytomegaloviral | 36 | 33.6 24.2–46.8ROR 33.7 · χ² 1,087 / p 1e-238 | 32.5 EB05 24.5 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=28 · ♀ 12% (drug 40%) | no trial data cached |
| Cytomegalovirus infection reactivation | 73 | 30.6 24.3–38.6ROR 30.8 · χ² 2,027 / p <1e-300 | 29.9 EB05 24.6 · IC025 +4.3 3/3 methods agree | Labeled (related wording) related wording | serious n=73 · 97% clinician | no trial data cached |
| Aplasia pure red cell | 58 | 30.2 23.3–39.1ROR 30.3 · χ² 1,580 / p <1e-300 | 29.4 EB05 23.6 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=48 | no trial data cached |
| Tumour lysis syndrome | 147 | 30.1 25.6–35.4ROR 30.5 · χ² 4,042 / p <1e-300 | 29.5 EB05 25.7 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 17.5 | no trial data cached |
| Plasma cell leukaemia | 10 | 29.9 16.0–55.8ROR 29.9 · χ² 247 / p 6e-56 | 27.9 EB05 16.0 · IC025 +2.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=10 | no trial data cached |
| Infusion site reaction | 48 | 29.6 22.2–39.3ROR 29.7 · χ² 1,274 / p 2e-279 | 28.8 EB05 22.6 · IC025 +4.0 3/3 methods agree | Labeled adverse reaction exact term | serious n=5 | no trial data cached |
| Cytomegalovirus infection | 271 | 29.2 25.9–32.8ROR 29.8 · χ² 7,225 / p <1e-300 | 28.6 EB05 25.9 · IC025 +4.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 23.1 · 93% clinician | no trial data cached |
| Progressive multifocal leukoencephalopathy | 128 | 27.7 23.3–33.0ROR 28.0 · χ² 3,222 / p <1e-300 | 27.2 EB05 23.5 · IC025 +4.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 20.9 · 91% clinician | no trial data cached |
| Cytomegalovirus viraemia | 67 | 27.4 21.5–34.8ROR 27.5 · χ² 1,650 / p <1e-300 | 26.8 EB05 21.8 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=64 · 95% clinician | no trial data cached |
| Diffuse large b-cell lymphoma refractory | 14 | 26.9 15.9–45.6ROR 26.9 · χ² 319 / p 1e-71 | 25.6 EB05 16.1 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=14 | 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 |
|---|---|---|---|---|---|---|
| Off label use (used outside approved label) | 1,133 | 2.3 2.2–2.4ROR 2.4 · χ² 867 / p 7e-191 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 3.3 | no trial data cached |
| Pyrexia (fever) | 861 | 4.4 4.1–4.7ROR 4.7 · χ² 2,281 / p <1e-300 | 4.4 EB05 4.1 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.1 | no trial data cached |
| Disease progression | 572 | 8.6 7.9–9.3ROR 9.0 · χ² 3,826 / p <1e-300 | 8.5 EB05 7.9 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 7.7 · 91% clinician | no trial data cached |
| Rash | 557 | 2.3 2.1–2.5ROR 2.3 · χ² 400 / p 3e-89 | 2.3 EB05 2.1 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Febrile neutropenia | 535 | 14.3 13.2–15.6ROR 15.0 · χ² 6,591 / p <1e-300 | 14.2 EB05 13.2 · IC025 +3.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.9 · 93% clinician | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 501 | 6.5 6.0–7.1ROR 6.8 · χ² 2,349 / p <1e-300 | 6.5 EB05 6.0 · IC025 +2.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 | no trial data cached |
| Pneumonia (lung infection) | 466 | 2.5 2.3–2.8ROR 2.6 · χ² 440 / p 5e-98 | 2.5 EB05 2.3 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Drug ineffective (drug did not work) | 448 | 0.6 0.5–0.7ROR 0.6 · χ² 128 / p 6e-30 | 0.6 EB05 0.6 · IC025 -0.9 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.3 · 92% clinician | no trial data cached |
| Platelet count decreased | 438 | 7.3 6.6–8.0ROR 7.5 · χ² 2,364 / p <1e-300 | 7.2 EB05 6.6 · IC025 +2.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.9 · 93% clinician | no trial data cached |
| Death | 424 | 0.9 0.8–1.0ROR 0.9 · χ² 9 / p 0.001 | 0.9 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Outcome field, not a reaction | serious PRR 0.5 | no trial data cached |
| Neutrophil count decreased | 422 | 18.5 16.9–20.4ROR 19.2 · χ² 6,921 / p <1e-300 | 18.3 EB05 16.9 · IC025 +4.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 14.8 · 94% clinician | no trial data cached |
| Product use in unapproved indication | 416 | 3.0 2.7–3.3ROR 3.1 · χ² 559 / p 6e-124 | 3.0 EB05 2.8 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 5.6 | no trial data cached |
| Covid-19 | 411 | 4.1 3.7–4.5ROR 4.2 · χ² 966 / p 3e-212 | 4.1 EB05 3.8 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 · 95% clinician | no trial data cached |
| Anaemia (low red blood cells) | 395 | 3.7 3.3–4.0ROR 3.7 · χ² 763 / p 3e-168 | 3.6 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.9 · 93% clinician | no trial data cached |
| Pancytopenia (all blood cells low) | 386 | 12.3 11.1–13.5ROR 12.7 · χ² 3,970 / p <1e-300 | 12.2 EB05 11.2 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.6 | 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.
- Erythropoiesis abnormal — n=25, PRR 157.3
- Cytomegalovirus enterocolitis — n=44, PRR 107.9
- Cytomegalovirus chorioretinitis — n=88, PRR 84.2
- Vasogenic cerebral oedema — n=28, PRR 72.6
- Post-acute covid-19 syndrome — n=28, PRR 40.8
- Hypogammaglobulinaemia — n=127, PRR 35.6
- Pneumonia cytomegaloviral — n=36, PRR 33.6
- Aplasia pure red cell — n=58, PRR 30.2
- Cytomegalovirus viraemia — n=67, PRR 27.4
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 Bendamustine?
In FDA FAERS, the most frequently co-reported reaction terms for Bendamustine are pyrexia, rash, febrile neutropenia, neutropenia, pneumonia, platelet count decreased. 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 Bendamustine have an FDA boxed warning?
No. The FDA label retrieved for Bendamustine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Bendamustine 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 766b73e2-49bb-47f9-bbb1-44cfa1a3197e, effective 20250210; matched on
openfda.generic_name.exact:"BENDAMUSTINE HYDROCHLORIDE") - 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, 999 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.