Drug · FAERS side-effect profile with label screen
Chlorambucil side effects: what 3,917 FDA adverse event reports show
Brand names
Leukeran
openFDA label
Who reports
3,917 reports · 93% serious · 925 with death outcome · 36% female
openFDA FAERS counts, all years, deduplication not applied
Used for
LEUKERAN (chlorambucil) is indicated in the treatment of chronic lymphatic (lymphocytic) leukemia, malignant lymphomas including lymphosarcoma, giant follicular lymphoma, and Hodgkin’s disease. It is not curative in any of these disorders but may produce clinically useful palliation.
FDA label, Indications and Usage
What it is
DESCRIPTION LEUKERAN (chlorambucil) was first synthesized by Everett et al. It is a bifunctional alkylating agent of the nitrogen mustard type that has been found active against selected human neoplastic diseases.
FDA label, Description section
Boxed warning
LEUKERAN (chlorambucil) can severely suppress bone marrow function. Chlorambucil is a carcinogen in humans. Chlorambucil is probably mutagenic and teratogenic in humans. Chlorambucil produces human infertility (see WARNINGS and PRECAUTIONS).
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 6Labeled (related wording) 2Likely indication confounding 3Reporting / coding artifact 4Lab value / disease marker 2Not in label — unassessed 22
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.
- 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. 97 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 |
|---|---|---|---|---|---|---|
| Acute myeloid leukaemia | 131 | 45.4 38.3–53.8ROR 46.9 · χ² 5,602 / p <1e-300 | 44.8 EB05 38.7 · IC025 +5.0 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 28.0 · ♀ 7% (drug 36%) · 92% clinician | no trial data cached |
| Myelodysplastic syndrome | 100 | 37.2 30.7–45.2ROR 38.2 · χ² 3,468 / p <1e-300 | 36.7 EB05 31.1 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 23.1 · 96% clinician | no trial data cached |
| Lymphopenia | 58 | 22.2 17.2–28.6ROR 22.5 · χ² 1,147 / p 1e-251 | 21.9 EB05 17.6 · IC025 +3.8 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 14.7 · 96% clinician | no trial data cached |
| Cytopenia | 46 | 20.7 15.5–27.6ROR 20.9 · χ² 839 / p 8e-185 | 20.4 EB05 15.9 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.6 · 96% clinician | no trial data cached |
| Squamous cell carcinoma | 31 | 17.7 12.4–25.1ROR 17.8 · χ² 469 / p 2e-104 | 17.4 EB05 12.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 10.9 | no trial data cached |
| Device related infection | 40 | 13.9 10.2–18.9ROR 14.0 · χ² 466 / p 1e-103 | 13.6 EB05 10.3 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 8.8 · ♀ 6% (drug 36%) · 98% clinician | no trial data cached |
| Febrile neutropenia | 162 | 13.1 11.3–15.3ROR 13.6 · χ² 1,804 / p <1e-300 | 13.0 EB05 11.4 · IC025 +3.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.1 · 95% clinician | no trial data cached |
| Respiratory tract infection | 61 | 12.6 9.8–16.2ROR 12.8 · χ² 639 / p 2e-141 | 12.4 EB05 9.9 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 · 98% clinician | no trial data cached |
| Blood lactate dehydrogenase increased | 33 | 11.1 7.9–15.6ROR 11.2 · χ² 293 / p 6e-66 | 10.5 EB05 7.6 · IC025 +2.7 3/3 methods agree | Lab value / disease marker | serious PRR 7.3 · ♀ 64% (drug 36%) | no trial data cached |
| Splenomegaly | 24 | 11.0 7.4–16.4ROR 11.1 · χ² 208 / p 2e-47 | 10.2 EB05 6.9 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Cytomegalovirus infection | 34 | 11.0 7.8–15.3ROR 11.0 · χ² 298 / p 6e-67 | 10.4 EB05 7.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 · 100% clinician | no trial data cached |
| Lung infection | 32 | 10.9 7.7–15.4ROR 11.0 · χ² 277 / p 1e-62 | 10.3 EB05 7.4 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.2 · ♀ 6% (drug 36%) · 97% clinician | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 275 | 10.9 9.7–12.2ROR 11.6 · χ² 2,470 / p <1e-300 | 10.8 EB05 9.8 · IC025 +3.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.8 · 92% clinician | no trial data cached |
| Thrombocytopenia (low platelets) | 192 | 9.2 8.0–10.6ROR 9.7 · χ² 1,406 / p <1e-300 | 9.1 EB05 8.1 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.7 · 93% clinician | no trial data cached |
| Lymphadenopathy | 59 | 8.9 6.9–11.5ROR 9.0 · χ² 407 / p 7e-91 | 8.6 EB05 6.8 · IC025 +2.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 6.6 | no trial data cached |
| Pneumocystis jirovecii pneumonia | 16 | 8.6 5.3–14.0ROR 8.6 · χ² 100 / p 9e-24 | 7.3 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Bone marrow failure | 32 | 8.4 5.9–11.8ROR 8.4 · χ² 201 / p 7e-46 | 7.7 EB05 5.6 · IC025 +2.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.2 · 90% clinician | no trial data cached |
| Infusion related reaction (reaction during infusion) | 101 | 8.2 6.8–9.9ROR 8.4 · χ² 632 / p 9e-140 | 8.0 EB05 6.7 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 · 98% clinician | no trial data cached |
| Skin infection | 16 | 7.7 4.7–12.5ROR 7.7 · χ² 86 / p 7e-21 | 6.5 EB05 4.2 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 | no trial data cached |
| Pancytopenia (all blood cells low) | 75 | 7.2 5.8–9.0ROR 7.3 · χ² 396 / p 2e-88 | 6.9 EB05 5.7 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.4 | no trial data cached |
| Disease progression | 156 | 7.1 6.1–8.3ROR 7.3 · χ² 813 / p 3e-179 | 7.0 EB05 6.1 · IC025 +2.5 3/3 methods agree | Reporting / coding artifact | serious PRR 4.8 · 92% clinician | no trial data cached |
| Leukocytosis | 21 | 6.2 4.1–9.5ROR 6.3 · χ² 87 / p 6e-21 | 5.5 EB05 3.8 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Basal cell carcinoma | 18 | 6.2 3.9–9.8ROR 6.2 · χ² 73 / p 7e-18 | 5.4 EB05 3.6 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Agranulocytosis (severe loss of white cells) | 21 | 6.1 4.0–9.3ROR 6.1 · χ² 84 / p 2e-20 | 5.4 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.8 | no trial data cached |
| Septic shock | 49 | 6.1 4.6–8.0ROR 6.1 · χ² 203 / p 2e-46 | 5.8 EB05 4.5 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 · 96% clinician | no trial data cached |
| Covid-19 pneumonia | 13 | 5.9 3.4–10.1ROR 5.9 · χ² 48 / p 3e-12 | 4.9 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 | no trial data cached |
| Haematotoxicity | 10 | 5.8 3.1–10.7ROR 5.8 · χ² 35 / p 2e-9 | 4.7 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 | no trial data cached |
| Haemorrhage intracranial | 16 | 5.7 3.5–9.3ROR 5.7 · χ² 58 / p 2e-14 | 5.0 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Tenderness | 11 | 5.6 3.1–10.2ROR 5.7 · χ² 37 / p 5e-10 | 4.7 EB05 2.8 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Lymphoma | 16 | 5.5 3.4–9.0ROR 5.6 · χ² 55 / p 6e-14 | 4.8 EB05 3.2 · IC025 +1.4 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 3.5 | no trial data cached |
| Nephropathy toxic | 11 | 5.3 2.9–9.5ROR 5.3 · χ² 34 / p 3e-9 | 4.4 EB05 2.6 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 | no trial data cached |
| Leukopenia (low white blood cells) | 49 | 5.3 4.0–7.0ROR 5.3 · χ² 165 / p 4e-38 | 5.0 EB05 3.9 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.3 | no trial data cached |
| Body temperature increased | 20 | 5.2 3.4–8.1ROR 5.3 · χ² 64 / p 5e-16 | 4.7 EB05 3.2 · IC025 +1.5 3/3 methods agree | Lab value / disease marker | serious PRR 4.0 · 95% clinician | no trial data cached |
| Incorrect product storage | 13 | 5.2 3.0–9.0ROR 5.2 · χ² 40 / p 1e-10 | 4.5 EB05 2.8 · IC025 +1.2 3/3 methods agree | Reporting / coding artifact | – | no trial data cached |
| Pneumonitis | 26 | 5.2 3.5–7.6ROR 5.2 · χ² 83 / p 4e-20 | 4.7 EB05 3.4 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 | no trial data cached |
| Transaminases increased | 21 | 5.1 3.3–7.8ROR 5.1 · χ² 64 / p 5e-16 | 4.6 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 · 100% clinician | no trial data cached |
| Neoplasm progression | 31 | 4.7 3.3–6.7ROR 4.8 · χ² 88 / p 4e-21 | 4.4 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 · ♀ 13% (drug 36%) · 94% clinician | no trial data cached |
| Cardiomyopathy | 13 | 4.7 2.7–8.1ROR 4.7 · χ² 34 / p 2e-9 | 4.1 EB05 2.6 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | no trial data cached |
| Intentional product use issue | 77 | 4.7 3.8–5.9ROR 4.8 · χ² 221 / p 3e-50 | 4.6 EB05 3.8 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 4.3 · 92% clinician | no trial data cached |
| Infection | 124 | 4.6 3.9–5.5ROR 4.7 · χ² 349 / p 4e-78 | 4.5 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.6 | 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 |
|---|---|---|---|---|---|---|
| Neutropenia (low neutrophils (infection-fighting cells)) | 275 | 10.9 9.7–12.2ROR 11.6 · χ² 2,470 / p <1e-300 | 10.8 EB05 9.8 · IC025 +3.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.8 · 92% clinician | no trial data cached |
| Pneumonia (lung infection) | 265 | 4.4 3.9–4.9ROR 4.6 · χ² 701 / p 9e-155 | 4.4 EB05 3.9 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.8 | no trial data cached |
| Pyrexia (fever) | 237 | 3.7 3.2–4.1ROR 3.8 · χ² 464 / p 3e-103 | 3.6 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.8 | no trial data cached |
| Thrombocytopenia (low platelets) | 192 | 9.2 8.0–10.6ROR 9.7 · χ² 1,406 / p <1e-300 | 9.1 EB05 8.1 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.7 · 93% clinician | no trial data cached |
| Febrile neutropenia | 162 | 13.1 11.3–15.3ROR 13.6 · χ² 1,804 / p <1e-300 | 13.0 EB05 11.4 · IC025 +3.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.1 · 95% clinician | no trial data cached |
| Anaemia (low red blood cells) | 157 | 4.4 3.8–5.1ROR 4.5 · χ² 413 / p 3e-92 | 4.4 EB05 3.8 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 | no trial data cached |
| Disease progression | 156 | 7.1 6.1–8.3ROR 7.3 · χ² 813 / p 3e-179 | 7.0 EB05 6.1 · IC025 +2.5 3/3 methods agree | Reporting / coding artifact | serious PRR 4.8 · 92% clinician | no trial data cached |
| Acute myeloid leukaemia | 131 | 45.4 38.3–53.8ROR 46.9 · χ² 5,602 / p <1e-300 | 44.8 EB05 38.7 · IC025 +5.0 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 28.0 · ♀ 7% (drug 36%) · 92% clinician | no trial data cached |
| Infection | 124 | 4.6 3.9–5.5ROR 4.7 · χ² 349 / p 4e-78 | 4.5 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Infusion related reaction (reaction during infusion) | 101 | 8.2 6.8–9.9ROR 8.4 · χ² 632 / p 9e-140 | 8.0 EB05 6.7 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 · 98% clinician | no trial data cached |
| Myelodysplastic syndrome | 100 | 37.2 30.7–45.2ROR 38.2 · χ² 3,468 / p <1e-300 | 36.7 EB05 31.1 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 23.1 · 96% clinician | no trial data cached |
| Sepsis (blood infection) | 89 | 4.3 3.5–5.2ROR 4.3 · χ² 221 / p 3e-50 | 4.2 EB05 3.5 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 · 91% clinician | no trial data cached |
| Malignant neoplasm progression | 83 | 4.4 3.5–5.4ROR 4.4 · χ² 213 / p 2e-48 | 4.3 EB05 3.6 · IC025 +1.7 3/3 methods agree | Reporting / coding artifact | serious PRR 2.7 · 93% clinician | no trial data cached |
| Cardiac disorder | 78 | 4.4 3.6–5.5ROR 4.5 · χ² 206 / p 5e-47 | 4.3 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 · ♀ 6% (drug 36%) | no trial data cached |
| Intentional product use issue | 77 | 4.7 3.8–5.9ROR 4.8 · χ² 221 / p 3e-50 | 4.6 EB05 3.8 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 4.3 · 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.
- Myelodysplastic syndrome — n=100, PRR 37.2
- Squamous cell carcinoma — n=31, PRR 17.7
- Respiratory tract infection — n=61, PRR 12.6
- Splenomegaly — n=24, PRR 11.0
- Cytomegalovirus infection — n=34, PRR 11.0
- Lung infection — n=32, PRR 10.9
- Infusion related reaction — n=101, PRR 8.2
- Leukocytosis — n=21, PRR 6.2
- Septic shock — n=49, PRR 6.1
- Pneumonitis — n=26, PRR 5.2
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 Chlorambucil?
In FDA FAERS, the most frequently co-reported reaction terms for Chlorambucil are neutropenia, pneumonia, pyrexia, thrombocytopenia, febrile neutropenia, anaemia. 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 Chlorambucil have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: LEUKERAN (chlorambucil) can severely suppress bone marrow function. Chlorambucil is a carcinogen in humans. Chlorambucil is probably mutagenic and teratogenic in humans. Chlorambucil produces human infertility (see WARNINGS and PRECAUTIONS).
Do FAERS signals prove that Chlorambucil 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 58a3c995-5ad6-465d-8437-5970c9088213, effective 20250108; matched on
openfda.generic_name.exact:"CHLORAMBUCIL") - 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, 137 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.