Lomustine side effects: what 2,533 FDA adverse event reports show
Who reports
2,533 reports · 69% serious · 575 with death outcome · 43% female
Used for
Lomustine Capsules are an alkylating drug indicated for the treatment of patients with: Brain tumors, primary and metastatic, following appropriate surgical and/or radiotherapeutic procedures. (1) Hodgkin’s lymphoma in combination with other chemotherapies, following disease progression with initial chemotherapy.
What it is
Lomustine Capsules, USP (lomustine) is an alkylating drug for oral administration.
Boxed warning
DELAYED MYELOSUPPRESSION and RISK OF OVERDOSAGE DELAYED MYELOSUPPRESSION Lomustine Capsules cause myelosuppression including fatal myelosuppression. Myelosuppression is delayed, dose-related, and cumulative; occurring 4 to 6 weeks after drug administration and persisting for 1 to 2 weeks. Thrombocytopenia is generally more severe than leukopenia.
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.
- 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. 36 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 |
|---|---|---|---|---|---|---|
| Haematotoxicity | 27 | 24.2 16.6–35.2ROR 24.4 · χ² 575 / p 2e-127 | 23.7 EB05 17.1 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious PRR 20.7 · 96% clinician | no trial data cached |
| Acute myeloid leukaemia | 38 | 20.2 14.8–27.8ROR 20.5 · χ² 675 / p 4e-149 | 20.0 EB05 15.2 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 17.0 · 100% clinician | no trial data cached |
| Blood count abnormal | 37 | 20.0 14.5–27.5ROR 20.2 · χ² 647 / p 6e-143 | 19.7 EB05 14.9 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 3.8 | no trial data cached |
| Myelodysplastic syndrome | 30 | 17.2 12.0–24.5ROR 17.4 · χ² 441 / p 4e-98 | 16.9 EB05 12.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 · 100% clinician | no trial data cached |
| Thrombocytopenia (low platelets) | 180 | 13.4 11.6–15.4ROR 14.3 · χ² 2,058 / p <1e-300 | 13.3 EB05 11.7 · IC025 +3.4 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 10.4 · 94% clinician | no trial data cached |
| Bone marrow failure | 32 | 13.0 9.2–18.3ROR 13.1 · χ² 341 / p 2e-76 | 12.5 EB05 9.1 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.8 · 90% clinician | no trial data cached |
| Hospice care | 15 | 12.6 7.6–20.9ROR 12.7 · χ² 149 / p 1e-34 | 11.4 EB05 6.7 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 | no trial data cached |
| Mucosal inflammation | 39 | 12.4 9.1–16.9ROR 12.6 · χ² 397 / p 1e-88 | 12.0 EB05 9.0 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.7 · ♀ 69% (drug 43%) · 92% clinician | no trial data cached |
| Hemiparesis | 24 | 11.7 7.8–17.4ROR 11.8 · χ² 223 / p 8e-51 | 10.9 EB05 7.4 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 10.5 | no trial data cached |
| Lymphopenia | 19 | 11.2 7.1–17.5ROR 11.3 · χ² 166 / p 3e-38 | 10.2 EB05 6.5 · IC025 +2.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 9.6 | no trial data cached |
| Neurotoxicity | 23 | 11.0 7.3–16.5ROR 11.1 · χ² 198 / p 2e-45 | 10.1 EB05 6.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 8.9 · 90% clinician | no trial data cached |
| Neoplasm progression | 46 | 10.9 8.2–14.5ROR 11.0 · χ² 402 / p 9e-90 | 10.5 EB05 8.0 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.7 | no trial data cached |
| Rebound effect | 14 | 10.2 6.1–17.3ROR 10.3 · χ² 107 / p 2e-25 | 8.7 EB05 5.2 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 13.7 | no trial data cached |
| Disease progression | 141 | 9.9 8.4–11.6ROR 10.4 · χ² 1,125 / p 5e-247 | 9.8 EB05 8.5 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 7.1 · 92% clinician | no trial data cached |
| Platelet count decreased | 112 | 8.7 7.3–10.4ROR 9.1 · χ² 760 / p 1e-167 | 8.5 EB05 7.2 · IC025 +2.8 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.1 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 130 | 7.9 6.7–9.4ROR 8.3 · χ² 787 / p 2e-173 | 7.8 EB05 6.7 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 · 96% clinician | no trial data cached |
| Ataxia | 11 | 7.6 4.2–13.8ROR 7.7 · χ² 57 / p 2e-14 | 6.1 EB05 3.5 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.9 | no trial data cached |
| Hepatic cytolysis | 11 | 7.5 4.1–13.5ROR 7.5 · χ² 55 / p 5e-14 | 5.9 EB05 3.5 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 | no trial data cached |
| Febrile neutropenia | 54 | 6.8 5.2–8.8ROR 6.9 · χ² 260 / p 1e-58 | 6.4 EB05 5.1 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 · 96% clinician | no trial data cached |
| Hepatotoxicity (liver damage) | 18 | 6.7 4.2–10.7ROR 6.8 · χ² 82 / p 6e-20 | 5.8 EB05 3.9 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 5.4 | no trial data cached |
| Lymphocyte count decreased | 14 | 6.6 3.9–11.1ROR 6.6 · χ² 60 / p 4e-15 | 5.5 EB05 3.5 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 6.2 | no trial data cached |
| Seizure | 88 | 6.4 5.2–7.8ROR 6.5 · χ² 393 / p 8e-88 | 6.2 EB05 5.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.0 | no trial data cached |
| Type 2 diabetes mellitus | 25 | 6.1 4.2–9.1ROR 6.2 · χ² 102 / p 2e-24 | 5.6 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 · ♀ 95% (drug 43%) · 100% clinician | no trial data cached |
| Blood pressure systolic increased | 14 | 5.9 3.5–10.0ROR 5.9 · χ² 52 / p 2e-13 | 5.0 EB05 3.2 · IC025 +1.4 3/3 methods agree | Lab value / disease marker | serious PRR 5.4 | no trial data cached |
| Malignant neoplasm progression | 71 | 5.8 4.6–7.3ROR 5.9 · χ² 277 / p 2e-62 | 5.6 EB05 4.6 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 4.7 | no trial data cached |
| Proteinuria | 13 | 5.7 3.3–9.8ROR 5.7 · χ² 46 / p 6e-12 | 4.8 EB05 3.0 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Leukopenia (low white blood cells) | 32 | 5.3 3.8–7.5ROR 5.4 · χ² 108 / p 1e-25 | 5.0 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.5 | no trial data cached |
| Red blood cell count decreased | 18 | 5.2 3.3–8.3ROR 5.2 · χ² 57 / p 2e-14 | 4.6 EB05 3.1 · IC025 +1.4 3/3 methods agree | Lab value / disease marker | serious PRR 3.5 | no trial data cached |
| Pancytopenia (all blood cells low) | 34 | 5.1 3.6–7.1ROR 5.1 · χ² 107 / p 3e-25 | 4.7 EB05 3.6 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 3.7 · 90% clinician | no trial data cached |
| Full blood count decreased | 12 | 4.9 2.8–8.7ROR 4.9 · χ² 34 / p 3e-9 | 4.2 EB05 2.6 · IC025 +1.1 3/3 methods agree | Lab value / disease marker | serious PRR 3.5 | no trial data cached |
| Osteonecrosis (bone death) | 19 | 4.7 3.0–7.4ROR 4.8 · χ² 53 / p 2e-13 | 4.3 EB05 2.9 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 | no trial data cached |
| White blood cell count decreased | 56 | 4.3 3.3–5.5ROR 4.3 · χ² 138 / p 4e-32 | 4.1 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 2.3 | no trial data cached |
| Multiple organ dysfunction syndrome | 14 | 4.2 2.5–7.0ROR 4.2 · χ² 30 / p 2e-8 | 3.7 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Liver injury | 12 | 4.1 2.3–7.2ROR 4.1 · χ² 25 / p 3e-7 | 3.6 EB05 2.2 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.0 | no trial data cached |
| Cognitive disorder | 23 | 4.1 2.7–6.2ROR 4.1 · χ² 51 / p 5e-13 | 3.8 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 | no trial data cached |
| Myelosuppression | 16 | 3.9 2.4–6.3ROR 3.9 · χ² 32 / p 9e-9 | 3.5 EB05 2.3 · IC025 +1.0 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 3.3 | no trial data cached |
| Neutrophil count decreased | 19 | 3.9 2.5–6.1ROR 3.9 · χ² 38 / p 4e-10 | 3.6 EB05 2.4 · IC025 +1.1 3/3 methods agree | Lab value / disease marker | serious PRR 2.6 | no trial data cached |
| Heart rate decreased | 16 | 3.8 2.3–6.1ROR 3.8 · χ² 30 / p 3e-8 | 3.4 EB05 2.3 · IC025 +1.0 3/3 methods agree | Lab value / disease marker | serious PRR 3.9 | no trial data cached |
| Drug resistance | 11 | 3.5 2.0–6.4ROR 3.6 · χ² 18 / p 1e-5 | 3.2 EB05 1.9 · IC025 +0.7 | Reporting / coding artifact | serious PRR 2.7 | no trial data cached |
| Speech disorder | 21 | 3.3 2.2–5.1ROR 3.3 · χ² 32 / p 9e-9 | 3.1 EB05 2.2 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 | 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 |
|---|---|---|---|---|---|---|
| Death | 262 | 2.5 2.2–2.8ROR 2.7 · χ² 249 / p 3e-56 | 2.5 EB05 2.3 · IC025 +1.1 3/3 methods agree | Outcome field, not a reaction boxed warning mentions mortality | serious PRR 2.1 | no trial data cached |
| Thrombocytopenia (low platelets) | 180 | 13.4 11.6–15.4ROR 14.3 · χ² 2,058 / p <1e-300 | 13.3 EB05 11.7 · IC025 +3.4 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 10.4 · 94% clinician | no trial data cached |
| Disease progression | 141 | 9.9 8.4–11.6ROR 10.4 · χ² 1,125 / p 5e-247 | 9.8 EB05 8.5 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 7.1 · 92% clinician | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 130 | 7.9 6.7–9.4ROR 8.3 · χ² 787 / p 2e-173 | 7.8 EB05 6.7 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.9 · 96% clinician | no trial data cached |
| Platelet count decreased | 112 | 8.7 7.3–10.4ROR 9.1 · χ² 760 / p 1e-167 | 8.5 EB05 7.2 · IC025 +2.8 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 4.1 | no trial data cached |
| Seizure | 88 | 6.4 5.2–7.8ROR 6.5 · χ² 393 / p 8e-88 | 6.2 EB05 5.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.0 | no trial data cached |
| Malignant neoplasm progression | 71 | 5.8 4.6–7.3ROR 5.9 · χ² 277 / p 2e-62 | 5.6 EB05 4.6 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 4.7 | no trial data cached |
| White blood cell count decreased | 56 | 4.3 3.3–5.5ROR 4.3 · χ² 138 / p 4e-32 | 4.1 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 2.3 | no trial data cached |
| Febrile neutropenia | 54 | 6.8 5.2–8.8ROR 6.9 · χ² 260 / p 1e-58 | 6.4 EB05 5.1 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 · 96% clinician | no trial data cached |
| Neoplasm progression | 46 | 10.9 8.2–14.5ROR 11.0 · χ² 402 / p 9e-90 | 10.5 EB05 8.0 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.7 | no trial data cached |
| Mucosal inflammation | 39 | 12.4 9.1–16.9ROR 12.6 · χ² 397 / p 1e-88 | 12.0 EB05 9.0 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.7 · ♀ 69% (drug 43%) · 92% clinician | no trial data cached |
| Acute myeloid leukaemia | 38 | 20.2 14.8–27.8ROR 20.5 · χ² 675 / p 4e-149 | 20.0 EB05 15.2 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 17.0 · 100% clinician | no trial data cached |
| Blood count abnormal | 37 | 20.0 14.5–27.5ROR 20.2 · χ² 647 / p 6e-143 | 19.7 EB05 14.9 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 3.8 | no trial data cached |
| Pancytopenia (all blood cells low) | 34 | 5.1 3.6–7.1ROR 5.1 · χ² 107 / p 3e-25 | 4.7 EB05 3.6 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 3.7 · 90% clinician | no trial data cached |
| Leukopenia (low white blood cells) | 32 | 5.3 3.8–7.5ROR 5.4 · χ² 108 / p 1e-25 | 5.0 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.5 | 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.
- Haematotoxicity — n=27, PRR 24.2
- Acute myeloid leukaemia — n=38, PRR 20.2
- Myelodysplastic syndrome — n=30, PRR 17.2
- Bone marrow failure — n=32, PRR 13.0
- Hemiparesis — n=24, PRR 11.7
- Neurotoxicity — n=23, PRR 11.0
- Neoplasm progression — n=46, PRR 10.9
- Neutropenia — n=130, PRR 7.9
- Febrile neutropenia — n=54, PRR 6.8
- Seizure — n=88, PRR 6.4
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 Lomustine?
In FDA FAERS, the most frequently co-reported reaction terms for Lomustine are thrombocytopenia, neutropenia, platelet count decreased, seizure, white blood cell count decreased, febrile neutropenia. 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 Lomustine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: DELAYED MYELOSUPPRESSION and RISK OF OVERDOSAGE DELAYED MYELOSUPPRESSION Lomustine Capsules cause myelosuppression including fatal myelosuppression. Myelosuppression is delayed, dose-related, and cumulative; occurring 4 to 6 weeks after drug administration and persisting for 1 to 2 weeks. Thrombocytopenia is generally more severe than leukopenia.
Do FAERS signals prove that Lomustine 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 916dfac8-da11-40e4-9e44-a909e29a6b5f, effective 20251028; matched on
openfda.generic_name.exact:"LOMUSTINE") - 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, 76 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.