Irinotecan side effects: what 12,785 FDA adverse event reports show
Drug class
Topoisomerase inhibitor
Label matched
Irinotecan Hydrochloride (Irinotecan Hydrochloride)
Who reports
12,785 reports · 92% serious · 2,639 with death outcome · 42% female
Used for
• Irinotecan Hydrochloride Injection, USP is indicated as a component of first-line therapy in combination with 5-fluorouracil (5-FU) and leucovorin (LV) for patients with metastatic carcinoma of the colon or rectum. • Irinotecan Hydrochloride Injectio.
What it is
Irinotecan Hydrochloride Injection, USP is an antineoplastic agent of the topoisomerase I inhibitor class. Irinotecan Hydrochloride Injection, USP is supplied as a sterile, pale yellow, clear, aqueous solution.
Boxed warning
DIARRHEA and MYELOSUPPRESSION • Early and late forms of diarrhea can occur. Early diarrhea may be accompanied by cholinergic symptoms which may be prevented or ameliorated by atropine. Late diarrhea can be life threatening and should be treated promptly with loperamide. Monitor patients with diarrhea and give fluid and electrolytes as needed.
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.
- 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. 973 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 |
|---|---|---|---|---|---|---|
| Desmoplastic small round cell tumour | 21 | 514.7 315.1–840.8ROR 515.5 · χ² 7,783 / p <1e-300 | 288.2 EB05 198.9 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=21 · 100% clinician | no trial data cached |
| Neuroblastoma | 25 | 116.2 77.5–174.3ROR 116.4 · χ² 2,558 / p <1e-300 | 100.4 EB05 71.5 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=24 · 100% clinician | no trial data cached |
| Neuroblastoma recurrent | 12 | 103.8 57.9–186.0ROR 103.9 · χ² 1,053 / p 2e-231 | 84.9 EB05 51.7 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Cholinergic syndrome | 33 | 88.8 62.6–126.0ROR 89.0 · χ² 2,634 / p <1e-300 | 80.5 EB05 60.0 · IC025 +4.7 3/3 methods agree | Labeled adverse reaction exact term | serious n=32 · 97% clinician | no trial data cached |
| Tumour perforation | 13 | 71.5 41.1–124.6ROR 71.6 · χ² 800 / p 3e-176 | 62.6 EB05 38.9 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Bacterial translocation | 13 | 70.1 40.2–122.1ROR 70.2 · χ² 784 / p 9e-173 | 61.5 EB05 38.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Subretinal fluid | 36 | 57.9 41.5–80.7ROR 58.0 · χ² 1,889 / p <1e-300 | 54.4 EB05 41.1 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=36 · 100% clinician | no trial data cached |
| Colorectal cancer metastatic | 77 | 57.1 45.5–71.6ROR 57.5 · χ² 4,047 / p <1e-300 | 54.5 EB05 45.0 · IC025 +5.0 3/3 methods agree | Labeled (related wording) related wording | serious n=77 · 92% clinician | no trial data cached |
| Carbohydrate antigen 19-9 increased | 17 | 55.6 34.3–90.1ROR 55.6 · χ² 829 / p 2e-182 | 50.9 EB05 33.6 · IC025 +3.6 3/3 methods agree | Lab value / disease marker | serious n=14 | no trial data cached |
| Portal venous gas | 11 | 52.8 29.0–96.2ROR 52.8 · χ² 492 / p 2e-109 | 47.3 EB05 28.2 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Rectal cancer metastatic | 10 | 48.7 26.0–91.4ROR 48.8 · χ² 409 / p 4e-91 | 43.7 EB05 25.3 · IC025 +2.8 3/3 methods agree | Labeled (related wording) related wording | serious n=10 | no trial data cached |
| Colon cancer metastatic | 40 | 41.9 30.6–57.3ROR 42.0 · χ² 1,516 / p <1e-300 | 40.1 EB05 30.7 · IC025 +4.2 3/3 methods agree | Labeled (related wording) related wording | serious n=38 | no trial data cached |
| Granulocyte count decreased | 42 | 39.6 29.1–53.7ROR 39.7 · χ² 1,504 / p <1e-300 | 38.0 EB05 29.3 · IC025 +4.2 3/3 methods agree | Lab value / disease marker | serious n=42 | no trial data cached |
| Ileal perforation | 15 | 37.8 22.7–63.0ROR 37.8 · χ² 490 / p 8e-109 | 35.4 EB05 22.8 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Dermatitis acneiform | 136 | 37.7 31.8–44.6ROR 38.1 · χ² 4,713 / p <1e-300 | 36.7 EB05 31.8 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=115 · 93% clinician | no trial data cached |
| Rectal perforation | 11 | 34.1 18.8–61.9ROR 34.1 · χ² 314 / p 1e-70 | 31.7 EB05 18.8 · IC025 +2.8 3/3 methods agree | Labeled (related wording) related wording | serious n=10 | no trial data cached |
| Myelosuppression | 686 | 33.7 31.3–36.3ROR 35.6 · χ² 21,352 / p <1e-300 | 33.0 EB05 31.0 · IC025 +4.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 20.4 | no trial data cached |
| Klebsiella test positive | 12 | 30.7 17.4–54.4ROR 30.7 · χ² 310 / p 1e-69 | 28.9 EB05 17.5 · IC025 +2.8 3/3 methods agree | Lab value / disease marker | serious n=12 | no trial data cached |
| Bone marrow depression | 18 | 30.4 19.1–48.5ROR 30.5 · χ² 474 / p 2e-105 | 29.1 EB05 19.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Protein urine | 16 | 29.5 18.0–48.4ROR 29.5 · χ² 405 / p 2e-90 | 28.1 EB05 18.3 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Malignant ascites | 13 | 28.3 16.3–48.9ROR 28.3 · χ² 310 / p 1e-69 | 26.8 EB05 16.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Glioblastoma multiforme | 14 | 27.5 16.2–46.7ROR 27.5 · χ² 326 / p 3e-73 | 26.2 EB05 16.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Paronychia | 71 | 27.3 21.6–34.6ROR 27.5 · χ² 1,747 / p <1e-300 | 26.7 EB05 21.9 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=69 · 99% clinician | no trial data cached |
| Biliary tract infection | 10 | 27.3 14.6–51.0ROR 27.3 · χ² 224 / p 7e-51 | 25.5 EB05 14.5 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Metastases to peritoneum | 40 | 26.6 19.5–36.3ROR 26.7 · χ² 945 / p 9e-208 | 25.9 EB05 19.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=40 · ♀ 63% (drug 42%) | no trial data cached |
| Nasal septum perforation | 10 | 25.7 13.8–48.0ROR 25.7 · χ² 210 / p 6e-48 | 24.1 EB05 13.6 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Neutropenic colitis | 31 | 25.0 17.6–35.7ROR 25.1 · χ² 681 / p 2e-150 | 24.4 EB05 18.0 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious n=31 · 94% clinician | no trial data cached |
| Cholangitis | 90 | 24.3 19.7–29.9ROR 24.5 · χ² 1,958 / p <1e-300 | 23.8 EB05 20.0 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=90 · 99% clinician | no trial data cached |
| Tumour necrosis | 15 | 23.7 14.3–39.5ROR 23.8 · χ² 300 / p 2e-67 | 22.7 EB05 14.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Pulmonary artery thrombosis | 11 | 23.7 13.1–43.0ROR 23.7 · χ² 214 / p 1e-48 | 22.3 EB05 12.9 · IC025 +2.5 3/3 methods agree | Labeled (related wording) related wording | serious n=11 | no trial data cached |
| Biliary obstruction | 17 | 22.6 14.0–36.4ROR 22.6 · χ² 325 / p 7e-73 | 21.7 EB05 14.2 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Carcinoembryonic antigen increased | 26 | 22.4 15.2–32.9ROR 22.4 · χ² 503 / p 1e-111 | 21.8 EB05 15.6 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious n=24 | no trial data cached |
| Enterocolitis | 75 | 21.8 17.4–27.4ROR 21.9 · χ² 1,450 / p <1e-300 | 21.4 EB05 17.7 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=74 · 94% clinician | no trial data cached |
| Skin toxicity | 69 | 20.5 16.2–26.0ROR 20.6 · χ² 1,247 / p 2e-273 | 20.2 EB05 16.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=68 · 94% clinician | no trial data cached |
| Enterocolitis infectious | 11 | 19.6 10.8–35.5ROR 19.6 · χ² 174 / p 5e-40 | 18.3 EB05 10.2 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Small intestinal perforation | 22 | 19.4 12.8–29.5ROR 19.4 · χ² 362 / p 6e-81 | 18.8 EB05 13.0 · IC025 +3.1 3/3 methods agree | Labeled (related wording) related wording | serious n=22 · ♀ 15% (drug 42%) | no trial data cached |
| Large intestine infection | 13 | 17.9 10.4–30.9ROR 17.9 · χ² 189 / p 3e-43 | 16.9 EB05 9.8 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Neoplasm progression | 378 | 17.8 16.1–19.7ROR 18.4 · χ² 5,938 / p <1e-300 | 17.6 EB05 16.2 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.5 | no trial data cached |
| Rectal cancer | 33 | 17.8 12.6–25.0ROR 17.8 · χ² 500 / p 6e-111 | 17.4 EB05 12.8 · IC025 +3.2 3/3 methods agree | Labeled adverse reaction exact term | serious n=28 · 94% clinician | no trial data cached |
| Gastrointestinal toxicity | 50 | 17.6 13.3–23.2ROR 17.7 · χ² 758 / p 4e-167 | 17.3 EB05 13.6 · IC025 +3.4 3/3 methods agree | Labeled (related wording) related wording | serious n=50 · 98% clinician | 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 |
|---|---|---|---|---|---|---|
| Diarrhoea (diarrhea) | 1,721 | 4.4 4.2–4.6ROR 4.9 · χ² 4,645 / p <1e-300 | 4.4 EB05 4.2 · IC025 +2.1 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.5 | no trial data cached |
| Off label use (used outside approved label) | 1,131 | 2.1 2.0–2.3ROR 2.2 · χ² 714 / p 2e-157 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 2.3 | no trial data cached |
| Nausea | 946 | 2.0 1.9–2.1ROR 2.0 · χ² 466 / p 9e-104 | 2.0 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 2.2 | no trial data cached |
| Death | 905 | 1.7 1.6–1.8ROR 1.8 · χ² 286 / p 2e-64 | 1.7 EB05 1.6 · IC025 +0.7 | Outcome field, not a reaction boxed warning mentions mortality | serious PRR 1.1 | no trial data cached |
| Vomiting | 847 | 3.0 2.8–3.2ROR 3.1 · χ² 1,126 / p 4e-247 | 3.0 EB05 2.8 · IC025 +1.5 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 2.7 | no trial data cached |
| Myelosuppression | 686 | 33.7 31.3–36.3ROR 35.6 · χ² 21,352 / p <1e-300 | 33.0 EB05 31.0 · IC025 +4.9 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 20.4 | no trial data cached |
| Disease progression | 678 | 9.5 8.8–10.2ROR 10.0 · χ² 5,133 / p <1e-300 | 9.4 EB05 8.8 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 6.0 · 91% clinician | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 618 | 7.5 7.0–8.1ROR 7.8 · χ² 3,488 / p <1e-300 | 7.4 EB05 7.0 · IC025 +2.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 4.8 · 93% clinician | no trial data cached |
| Febrile neutropenia | 612 | 15.3 14.1–16.5ROR 16.0 · χ² 8,110 / p <1e-300 | 15.1 EB05 14.2 · IC025 +3.8 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 9.4 · 97% clinician | no trial data cached |
| Malignant neoplasm progression | 593 | 9.6 8.9–10.4ROR 10.0 · χ² 4,555 / p <1e-300 | 9.5 EB05 8.9 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 6.1 | no trial data cached |
| Fatigue (tiredness) | 577 | 1.2 1.1–1.3ROR 1.2 · χ² 23 / p 7e-7 | 1.2 EB05 1.1 · IC025 +0.1 | Labeled (related wording) related wording | serious PRR 1.4 | no trial data cached |
| Pyrexia (fever) | 551 | 2.6 2.4–2.8ROR 2.7 · χ² 555 / p 4e-123 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 2.0 | no trial data cached |
| Asthenia (weakness) | 501 | 2.2 2.0–2.4ROR 2.2 · χ² 327 / p 2e-73 | 2.2 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.9 | no trial data cached |
| Neuropathy peripheral (nerve damage in hands/feet) | 466 | 8.1 7.4–8.9ROR 8.4 · χ² 2,901 / p <1e-300 | 8.0 EB05 7.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | no trial data cached |
| Abdominal pain | 463 | 3.3 3.0–3.6ROR 3.4 · χ² 735 / p 5e-162 | 3.3 EB05 3.0 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.6 | 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.
- Desmoplastic small round cell tumour — n=21, PRR 514.7
- Neuroblastoma — n=25, PRR 116.2
- Subretinal fluid — n=36, PRR 57.9
- Dermatitis acneiform — n=136, PRR 37.7
- Paronychia — n=71, PRR 27.3
- Metastases to peritoneum — n=40, PRR 26.6
- Cholangitis — n=90, PRR 24.3
- Enterocolitis — n=75, PRR 21.8
- Skin toxicity — n=69, PRR 20.5
- Neoplasm progression — n=378, PRR 17.8
✓ A hand-written Bradford Hill causality assessment exists for this drug: Irinotecan ↔ Diarrhoea.
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 Irinotecan?
In FDA FAERS, the most frequently co-reported reaction terms for Irinotecan are diarrhoea, nausea, vomiting, myelosuppression, neutropenia, 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 Irinotecan have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: DIARRHEA and MYELOSUPPRESSION • Early and late forms of diarrhea can occur. Early diarrhea may be accompanied by cholinergic symptoms which may be prevented or ameliorated by atropine. Late diarrhea can be life threatening and should be treated promptly with loperamide. Monitor patients with diarrhea and give fluid and electrolytes as needed.
Do FAERS signals prove that Irinotecan 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 5c527c2e-9062-4afe-dbbb-f650db3a340f, effective 20251103; matched on
openfda.generic_name.exact:"IRINOTECAN 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, 1,013 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.