Imatinib Mesylate side effects: what 27,726 FDA adverse event reports show
Drug class
Not stated in label
Brand names
Imatinib Mesylate
Who reports
27,726 reports · 75% serious · 6,794 with death outcome · 50% female
Used for
Imatinib mesylate tablets are a kinase inhibitor indicated for the treatment of: • Newly diagnosed adult and pediatric patients with Philadelphia chromosome positive chronic myeloid leukemia (Ph+ CML) in chronic phase. ( 1.1 ) • Patients with Philadelp.
What it is
Imatinib is a small molecule kinase inhibitor. Imatinib mesylate film-coated tablets are supplied as 100 mg or 400 mg tablets for oral administration. Each 100 mg tablet contains 119.5 mg of imatinib mesylate equivalent to 100 mg of imatinib free base.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
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.
- 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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,107 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 |
|---|---|---|---|---|---|---|
| Chromosome analysis abnormal | 60 | 229.3 171.8–306.2ROR 229.8 · calibrated p 3e-10 ✓ | 166.4 EB05 134.0 · IC025 +5.7 3/3 methods agree | Reporting / coding artifact | serious n=57 | no trial data cached |
| Gastrointestinal stromal tumour | 476 | 163.6 148.3–180.6ROR 166.5 · calibrated p 2e-9 ✓ | 133.7 EB05 123.9 · IC025 +6.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=469 | no trial data cached |
| Gene mutation identification test positive | 73 | 156.8 121.9–201.8ROR 157.2 · calibrated p 5e-9 ✓ | 125.5 EB05 103.2 · IC025 +5.7 3/3 methods agree | Lab value / disease marker | serious n=71 | no trial data cached |
| Blast crisis in myelogenous leukaemia | 181 | 129.7 110.8–151.8ROR 130.6 · calibrated p 2e-8 ✓ | 109.4 EB05 96.6 · IC025 +6.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=180 | no trial data cached |
| Malignant tumour excision | 12 | 101.6 55.6–185.8ROR 101.7 · calibrated p 9e-7 ✓ | 78.7 EB05 48.0 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Chronic myeloid leukaemia transformation | 44 | 82.8 60.7–113.1ROR 82.9 · calibrated p 8e-7 ✓ | 72.4 EB05 56.1 · IC025 +4.9 3/3 methods agree | Labeled (related wording) related wording | serious n=44 · ♀ 29% (drug 50%) | no trial data cached |
| Chronic myeloid leukaemia | 443 | 80.0 72.6–88.2ROR 81.3 · calibrated p 5e-7 ✓ | 72.2 EB05 66.7 · IC025 +5.9 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=439 | no trial data cached |
| Cytogenetic analysis abnormal | 91 | 71.5 57.7–88.6ROR 71.7 · calibrated p 2e-6 ✓ | 64.5 EB05 54.1 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious n=45 | no trial data cached |
| Blast cell crisis | 25 | 61.1 40.6–91.8ROR 61.1 · calibrated p 8e-6 ✓ | 54.3 EB05 38.7 · IC025 +4.1 3/3 methods agree | Labeled (related wording) related wording | serious n=25 | no trial data cached |
| Amaurosis fugax | 73 | 55.3 43.6–70.2ROR 55.5 · calibrated p 9e-6 ✓ | 50.9 EB05 41.9 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=73 · 94% clinician | no trial data cached |
| Chronic myeloid leukaemia recurrent | 33 | 48.4 34.1–68.8ROR 48.5 · calibrated p 3e-5 ✓ | 44.4 EB05 33.1 · IC025 +4.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=33 · ♀ 72% (drug 50%) | no trial data cached |
| Cd4 lymphocytes increased | 14 | 47.6 27.8–81.8ROR 47.7 · calibrated p 6e-5 ✓ | 42.4 EB05 26.9 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious n=14 | no trial data cached |
| Bone marrow necrosis | 13 | 44.0 25.2–77.1ROR 44.1 · calibrated p 1e-4 ✓ | 39.4 EB05 24.5 · IC025 +3.1 3/3 methods agree | Labeled (related wording) related wording | serious n=12 | no trial data cached |
| Leukaemia recurrent | 90 | 42.5 34.4–52.5ROR 42.6 · calibrated p 4e-5 ✓ | 39.9 EB05 33.5 · IC025 +4.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=89 | no trial data cached |
| Orbital oedema | 26 | 40.6 27.4–60.3ROR 40.7 · calibrated p 9e-5 ✓ | 37.6 EB05 27.0 · IC025 +3.8 3/3 methods agree | Labeled adverse reaction exact term | serious n=23 | no trial data cached |
| Tumour excision | 40 | 39.6 28.9–54.5ROR 39.7 · calibrated p 8e-5 ✓ | 37.1 EB05 28.4 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=35 | no trial data cached |
| Periorbital oedema | 249 | 38.1 33.6–43.3ROR 38.4 · calibrated p 7e-5 ✓ | 36.2 EB05 32.6 · IC025 +4.9 3/3 methods agree | Labeled adverse reaction exact term | serious n=212 | no trial data cached |
| Blast cells present | 23 | 38.1 25.1–57.9ROR 38.1 · calibrated p 1e-4 ✓ | 35.3 EB05 24.8 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious n=23 | no trial data cached |
| Transmission of drug via semen | 21 | 34.0 21.9–52.6ROR 34.0 · calibrated p 3e-4 ✓ | 31.7 EB05 21.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=21 | no trial data cached |
| Chloroma | 18 | 33.6 21.0–53.9ROR 33.6 · calibrated p 3e-4 ✓ | 31.3 EB05 20.9 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Thrombocythaemia | 22 | 30.9 20.2–47.4ROR 31.0 · calibrated p 4e-4 ✓ | 29.1 EB05 20.2 · IC025 +3.5 3/3 methods agree | Labeled adverse reaction exact term | serious n=22 · 100% clinician | no trial data cached |
| Gastric antral vascular ectasia | 20 | 30.2 19.3–47.3ROR 30.3 · calibrated p 5e-4 ✓ | 28.4 EB05 19.4 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious n=20 | no trial data cached |
| Philadelphia chromosome positive | 27 | 29.6 20.1–43.5ROR 29.6 · calibrated p 4e-4 ✓ | 28.0 EB05 20.2 · IC025 +3.6 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=25 | no trial data cached |
| Mastocytosis | 16 | 27.0 16.4–44.4ROR 27.0 · calibrated p 9e-4 ✓ | 25.4 EB05 16.5 · IC025 +3.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=13 | no trial data cached |
| Neoplasm recurrence | 115 | 26.5 22.0–31.9ROR 26.6 · calibrated p 5e-4 ✓ | 25.5 EB05 21.8 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=110 | no trial data cached |
| Biopsy bone marrow abnormal | 15 | 25.5 15.3–42.7ROR 25.5 · calibrated p 0.001 ✓ | 24.0 EB05 15.3 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Recurrent cancer | 132 | 25.4 21.4–30.2ROR 25.6 · calibrated p 7e-4 ✓ | 24.6 EB05 21.2 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=131 · 73% consumer | no trial data cached |
| Aspiration pleural cavity | 23 | 23.2 15.3–35.1ROR 23.2 · calibrated p 0.002 ✓ | 22.1 EB05 15.5 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=23 · ♀ 73% (drug 50%) | no trial data cached |
| Gastrectomy | 29 | 22.3 15.4–32.2ROR 22.3 · calibrated p 0.002 ✓ | 21.4 EB05 15.6 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=29 | no trial data cached |
| Full blood count increased | 30 | 19.4 13.5–27.9ROR 19.5 · calibrated p 0.003 ✓ | 18.7 EB05 13.7 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious n=17 · 100% consumer | no trial data cached |
| Marrow hyperplasia | 17 | 19.1 11.8–31.0ROR 19.2 · calibrated p 0.004 ✓ | 18.2 EB05 11.7 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Eye oedema | 59 | 18.6 14.4–24.1ROR 18.6 · calibrated p 0.003 ✓ | 18.1 EB05 14.5 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious n=47 · ♀ 78% (drug 50%) | no trial data cached |
| Leukaemia | 225 | 18.5 16.2–21.1ROR 18.6 · calibrated p 0.003 ✓ | 18.0 EB05 16.1 · IC025 +3.9 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 13.9 · 82% consumer | no trial data cached |
| Bone marrow transplant | 44 | 18.0 13.4–24.3ROR 18.1 · calibrated p 0.004 ✓ | 17.5 EB05 13.5 · IC025 +3.4 3/3 methods agree | Labeled (related wording) related wording | serious n=43 | no trial data cached |
| Tumour necrosis | 24 | 17.7 11.8–26.5ROR 17.7 · calibrated p 0.005 ✓ | 16.9 EB05 11.8 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious n=24 | no trial data cached |
| Hypereosinophilic syndrome | 12 | 17.4 9.8–30.9ROR 17.4 · calibrated p 0.007 ✓ | 16.0 EB05 8.9 · IC025 +2.4 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=11 | no trial data cached |
| Bone marrow depression | 21 | 16.4 10.6–25.3ROR 16.4 · calibrated p 0.007 ✓ | 15.6 EB05 10.4 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious n=21 | no trial data cached |
| Bone marrow oedema | 21 | 15.6 10.1–24.0ROR 15.6 · calibrated p 0.008 ✓ | 14.8 EB05 9.8 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious n=21 · 100% clinician | no trial data cached |
| Acute lymphocytic leukaemia | 56 | 15.2 11.7–19.8ROR 15.3 · calibrated p 0.007 ✓ | 14.8 EB05 11.8 · IC025 +3.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=56 | no trial data cached |
| Second primary malignancy | 161 | 14.9 12.8–17.4ROR 15.0 · calibrated p 0.007 ✓ | 14.6 EB05 12.8 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 11.2 | 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 | 4,637 | 4.1 4.0–4.2ROR 4.7 · calibrated p 0.268 | 4.1 EB05 4.0 · IC025 +2.0 3/3 methods agree | Outcome field, not a reaction | serious PRR 3.1 | no trial data cached |
| Nausea | 2,136 | 2.1 2.0–2.1ROR 2.1 · calibrated p 0.983 | 2.0 EB05 2.0 · IC025 +1.0 | Labeled adverse reaction exact term | serious PRR 2.0 | no trial data cached |
| Diarrhoea (diarrhea) | 1,770 | 2.1 2.0–2.2ROR 2.2 · calibrated p 0.973 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.0 | no trial data cached |
| Fatigue (tiredness) | 1,524 | 1.5 1.4–1.6ROR 1.5 · calibrated p 0.650 | 1.5 EB05 1.4 · IC025 +0.5 | Labeled adverse reaction exact term | serious PRR 1.5 | no trial data cached |
| Drug ineffective (drug did not work) | 1,396 | 0.8 0.8–0.8ROR 0.8 · calibrated p 0.179 | 0.8 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.9 | no trial data cached |
| Vomiting | 1,288 | 2.1 2.0–2.2ROR 2.1 · calibrated p 0.985 | 2.1 EB05 2.0 · IC025 +1.0 | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Malaise (feeling unwell) | 1,080 | 1.9 1.8–2.0ROR 1.9 · calibrated p 0.886 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.3 | no trial data cached |
| Rash | 1,003 | 1.8 1.6–1.9ROR 1.8 · calibrated p 0.818 | 1.7 EB05 1.7 · IC025 +0.7 | Labeled adverse reaction exact term | serious PRR 2.0 | no trial data cached |
| Dyspnoea (shortness of breath) | 993 | 1.3 1.2–1.4ROR 1.3 · calibrated p 0.536 | 1.3 EB05 1.3 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.2 | no trial data cached |
| Muscle spasms | 860 | 3.6 3.3–3.8ROR 3.6 · calibrated p 0.453 | 3.5 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.5 | no trial data cached |
| Neoplasm malignant | 846 | 9.7 9.1–10.4ROR 10.0 · calibrated p 0.033 ✓ | 9.6 EB05 9.0 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 7.4 | no trial data cached |
| Asthenia (weakness) | 802 | 1.6 1.5–1.7ROR 1.6 · calibrated p 0.727 | 1.6 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.4 | no trial data cached |
| Pyrexia (fever) | 770 | 1.7 1.6–1.8ROR 1.7 · calibrated p 0.771 | 1.7 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.5 | no trial data cached |
| Anaemia (low red blood cells) | 718 | 2.9 2.7–3.1ROR 2.9 · calibrated p 0.659 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.2 | no trial data cached |
| Malignant neoplasm progression | 681 | 5.1 4.7–5.5ROR 5.2 · calibrated p 0.216 | 5.0 EB05 4.7 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 3.9 | 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.
- Amaurosis fugax — n=73, PRR 55.3
- Tumour excision — n=40, PRR 39.6
- Transmission of drug via semen — n=21, PRR 34.0
- Neoplasm recurrence — n=115, PRR 26.5
- Recurrent cancer — n=132, PRR 25.4
- Aspiration pleural cavity — n=23, PRR 23.2
- Gastrectomy — n=29, PRR 22.3
✓ A hand-written Bradford Hill causality assessment exists for this drug: Imatinib ↔ Fluid retention / oedema.
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 Imatinib?
In FDA FAERS, the most frequently co-reported reaction terms for Imatinib are nausea, diarrhoea, fatigue, vomiting, malaise, rash. 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 Imatinib have an FDA boxed warning?
No. The FDA label retrieved for Imatinib has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Imatinib 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 a1787fad-3612-43e1-98fa-ce62361e0b3c, effective 20260715; matched on
openfda.generic_name.exact:"IMATINIB") - 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, 1,147 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 2026-10-14. 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.