Drug · FAERS side-effect profile with label screen
Cladribine side effects: what 9,531 FDA adverse event reports show
Who reports
9,531 reports · 75% serious · 709 with death outcome · 70% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Cladribine tablets are indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include relapsing-remitting disease and active secondary progressive disease in adults. Because of its safety profile, use of cladribine tablets is gen.
FDA label, Indications and Usage
What it is
Cladribine tablets contains the nucleoside metabolic inhibitor cladribine, which is a white to off-white crystalline powder with the molecular formula C 10 H 12 ClN 5 O 3 and molecular weight 285.69 g/mol.
FDA label, Description section
Boxed warning
MALIGNANCIES AND RISK OF TERATOGENICITY Malignancies Treatment with cladribine tablets may increase the risk of malignancy. Cladribine tablets are contraindicated in patients with current malignancy. In patients with.
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 1Labeled (related wording) 3Likely indication confounding 2Reporting / coding artifact 3Lab value / disease marker 5Not in label — unassessed 25
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. 978 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 |
|---|---|---|---|---|---|---|
| Hairy cell leukaemia recurrent | 16 | 1,443.1 766.8–2,715.7ROR 1,445.5 · χ² 12,982 / p <1e-300 | 424.7 EB05 277.2 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Gastrointestinal protozoal infection | 10 | 1,352.9 614.1–2,980.5ROR 1,354.3 · χ² 7,502 / p <1e-300 | 321.1 EB05 186.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Hairy cell leukaemia | 19 | 196.8 123.1–314.6ROR 197.2 · χ² 3,215 / p <1e-300 | 153.0 EB05 103.5 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Multiple sclerosis pseudo relapse | 17 | 119.1 73.1–194.0ROR 119.3 · χ² 1,777 / p <1e-300 | 100.5 EB05 66.5 · IC025 +3.9 3/3 methods agree | Labeled (related wording) related wording | serious n=15 | no trial data cached |
| Autoimmune thrombocytopenia | 18 | 93.9 58.6–150.4ROR 94.1 · χ² 1,498 / p <1e-300 | 82.4 EB05 55.2 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Systemic mastocytosis | 10 | 79.3 42.2–149.0ROR 79.4 · χ² 672 / p 2e-148 | 67.2 EB05 39.0 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Intercepted product prescribing error | 37 | 64.5 46.5–89.4ROR 64.7 · χ² 2,185 / p <1e-300 | 60.8 EB05 46.1 · IC025 +4.6 3/3 methods agree | Labeled (related wording) related wording | 77% consumer | no trial data cached |
| Lymphocyte count decreased | 488 | 62.3 57.0–68.0ROR 65.6 · χ² 28,556 / p <1e-300 | 60.4 EB05 56.0 · IC025 +5.7 3/3 methods agree | Lab value / disease marker | serious PRR 45.6 | no trial data cached |
| Anaemia haemolytic autoimmune | 22 | 59.0 38.7–90.1ROR 59.1 · χ² 1,166 / p 9e-256 | 54.9 EB05 38.2 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=22 · 100% clinician | no trial data cached |
| Relapsing-remitting multiple sclerosis | 16 | 41.4 25.3–67.9ROR 41.5 · χ² 580 / p 2e-128 | 38.9 EB05 25.4 · IC025 +3.4 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=16 | no trial data cached |
| Lymphopenia | 230 | 36.5 32.1–41.5ROR 37.3 · χ² 7,771 / p <1e-300 | 35.8 EB05 32.1 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 24.8 | no trial data cached |
| Acute myeloid leukaemia recurrent | 30 | 31.3 21.9–44.9ROR 31.4 · χ² 839 / p 1e-184 | 30.4 EB05 22.3 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=30 · 100% clinician | no trial data cached |
| Maternal exposure before pregnancy | 90 | 29.4 23.9–36.2ROR 29.7 · χ² 2,413 / p <1e-300 | 28.9 EB05 24.2 · IC025 +4.3 3/3 methods agree | Reporting / coding artifact | serious n=87 · ♀ 100% (drug 70%) | no trial data cached |
| Expanded disability status scale score increased | 16 | 28.6 17.4–46.7ROR 28.6 · χ² 393 / p 9e-88 | 27.4 EB05 17.8 · IC025 +3.1 3/3 methods agree | Lab value / disease marker | serious n=16 | no trial data cached |
| Jc polyomavirus test positive | 14 | 26.4 15.6–44.7ROR 26.4 · χ² 313 / p 2e-70 | 25.3 EB05 15.9 · IC025 +2.9 3/3 methods agree | Lab value / disease marker | serious n=9 | no trial data cached |
| Maternal exposure timing unspecified | 44 | 26.3 19.5–35.3ROR 26.4 · χ² 1,031 / p 1e-226 | 25.7 EB05 19.9 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious n=42 · ♀ 100% (drug 70%) | no trial data cached |
| Bradyarrhythmia | 19 | 25.7 16.3–40.4ROR 25.7 · χ² 422 / p 6e-94 | 24.8 EB05 16.8 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=19 | no trial data cached |
| Magnetic resonance imaging abnormal | 12 | 22.6 12.8–39.9ROR 22.6 · χ² 224 / p 6e-51 | 21.5 EB05 12.7 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious n=12 | no trial data cached |
| Leukaemia recurrent | 17 | 22.3 13.8–35.9ROR 22.3 · χ² 321 / p 4e-72 | 21.5 EB05 14.1 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Exposure to sars-cov-2 | 15 | 19.3 11.6–32.1ROR 19.3 · χ² 240 / p 2e-54 | 18.5 EB05 11.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Band sensation | 11 | 19.0 10.5–34.5ROR 19.1 · χ² 169 / p 6e-39 | 17.8 EB05 9.8 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=7 | no trial data cached |
| Monocyte count decreased | 10 | 18.3 9.8–34.0ROR 18.3 · χ² 145 / p 1e-33 | 16.8 EB05 8.6 · IC025 +2.2 3/3 methods agree | Lab value / disease marker | serious n=10 | no trial data cached |
| Multiple sclerosis relapse | 474 | 15.1 13.9–16.5ROR 15.9 · χ² 6,225 / p <1e-300 | 15.0 EB05 13.9 · IC025 +3.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.6 | no trial data cached |
| Cutaneous vasculitis | 23 | 14.2 9.4–21.4ROR 14.3 · χ² 268 / p 2e-60 | 13.6 EB05 9.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=23 · ♀ 19% (drug 70%) · 91% clinician | no trial data cached |
| Vertigo positional | 11 | 13.9 7.7–25.1ROR 13.9 · χ² 118 / p 8e-28 | 12.2 EB05 6.3 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=9 | no trial data cached |
| Graft versus host disease in gastrointestinal tract | 13 | 13.5 7.8–23.2ROR 13.5 · χ² 137 / p 6e-32 | 12.1 EB05 6.7 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Spleen disorder | 10 | 13.0 7.0–24.2ROR 13.0 · χ² 98 / p 2e-23 | 10.9 EB05 5.5 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Myelodysplastic syndrome | 82 | 12.5 10.1–15.5ROR 12.6 · χ² 852 / p 2e-187 | 12.3 EB05 10.2 · IC025 +3.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.7 · ♀ 25% (drug 70%) · 90% clinician | no trial data cached |
| Multiple sclerosis | 258 | 11.8 10.5–13.4ROR 12.1 · χ² 2,541 / p <1e-300 | 11.7 EB05 10.6 · IC025 +3.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 9.7 | no trial data cached |
| Abortion | 15 | 11.3 6.8–18.7ROR 11.3 · χ² 130 / p 3e-30 | 9.9 EB05 5.9 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Atypical pneumonia | 15 | 11.1 6.7–18.4ROR 11.1 · χ² 127 / p 8e-30 | 9.7 EB05 5.8 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Stem cell transplant | 12 | 10.7 6.1–18.9ROR 10.7 · χ² 96 / p 7e-23 | 8.9 EB05 5.0 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Invasive ductal breast carcinoma | 13 | 10.5 6.1–18.1ROR 10.5 · χ² 102 / p 2e-24 | 8.9 EB05 5.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Gastrointestinal toxicity | 22 | 10.3 6.8–15.6ROR 10.3 · χ² 175 / p 4e-40 | 9.3 EB05 6.2 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=22 · 100% clinician | no trial data cached |
| Blood immunoglobulin g decreased | 11 | 9.9 5.5–18.0ROR 10.0 · χ² 79 / p 2e-19 | 8.0 EB05 4.4 · IC025 +1.8 3/3 methods agree | Lab value / disease marker | serious n=7 | no trial data cached |
| Haematotoxicity | 40 | 9.5 7.0–13.0ROR 9.5 · χ² 295 / p 2e-66 | 9.0 EB05 6.7 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.5 · ♀ 41% (drug 70%) · 100% clinician | no trial data cached |
| Optic neuritis | 39 | 9.4 6.9–12.9ROR 9.5 · χ² 284 / p 5e-64 | 8.9 EB05 6.6 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 | no trial data cached |
| Rash maculo-papular | 94 | 9.3 7.6–11.4ROR 9.4 · χ² 690 / p 2e-152 | 9.1 EB05 7.6 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.7 · ♀ 43% (drug 70%) · 100% clinician | no trial data cached |
| Adenovirus infection | 12 | 9.2 5.2–16.2ROR 9.2 · χ² 80 / p 2e-19 | 7.5 EB05 4.3 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Escherichia sepsis | 12 | 9.1 5.2–16.1ROR 9.1 · χ² 79 / p 4e-19 | 7.4 EB05 4.3 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=12 | 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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 814 | 2.3 2.2–2.5ROR 2.4 · χ² 620 / p 4e-137 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.4 · 79% consumer | no trial data cached |
| Headache | 681 | 2.4 2.2–2.6ROR 2.5 · χ² 565 / p 4e-125 | 2.4 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.3 · 73% consumer | no trial data cached |
| Lymphocyte count decreased | 488 | 62.3 57.0–68.0ROR 65.6 · χ² 28,556 / p <1e-300 | 60.4 EB05 56.0 · IC025 +5.7 3/3 methods agree | Lab value / disease marker | serious PRR 45.6 | no trial data cached |
| Multiple sclerosis relapse | 474 | 15.1 13.9–16.5ROR 15.9 · χ² 6,225 / p <1e-300 | 15.0 EB05 13.9 · IC025 +3.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.6 | no trial data cached |
| Nausea | 423 | 1.2 1.1–1.3ROR 1.2 · χ² 11 / p 4e-4 | 1.2 EB05 1.1 · IC025 +0.1 | Labeled adverse reaction exact term | serious PRR 0.9 | no trial data cached |
| Pneumonia (lung infection) | 406 | 2.8 2.5–3.0ROR 2.8 · χ² 460 / p 2e-102 | 2.8 EB05 2.5 · IC025 +1.3 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 2.2 | no trial data cached |
| White blood cell count decreased | 363 | 7.4 6.7–8.1ROR 7.6 · χ² 1,993 / p <1e-300 | 7.3 EB05 6.7 · IC025 +2.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.7 · 71% consumer | no trial data cached |
| Off label use (used outside approved label) | 330 | 0.8 0.8–0.9ROR 0.8 · χ² 11 / p 4e-4 | 0.8 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.1 · ♀ 38% (drug 70%) · 94% clinician | no trial data cached |
| Drug ineffective (drug did not work) | 291 | 0.5 0.4–0.5ROR 0.5 · χ² 169 / p 5e-39 | 0.5 EB05 0.4 · IC025 -1.2 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.9 · ♀ 46% (drug 70%) | no trial data cached |
| Pyrexia (fever) | 287 | 1.8 1.6–2.0ROR 1.8 · χ² 107 / p 2e-25 | 1.8 EB05 1.6 · IC025 +0.7 | Labeled (related wording) related wording | serious PRR 1.6 · ♀ 49% (drug 70%) | no trial data cached |
| Urinary tract infection (bladder infection) | 280 | 3.6 3.2–4.1ROR 3.7 · χ² 531 / p 8e-118 | 3.6 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.1 · 74% consumer | no trial data cached |
| Multiple sclerosis | 258 | 11.8 10.5–13.4ROR 12.1 · χ² 2,541 / p <1e-300 | 11.7 EB05 10.6 · IC025 +3.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 9.7 | no trial data cached |
| Asthenia (weakness) | 244 | 1.4 1.3–1.6ROR 1.4 · χ² 31 / p 1e-8 | 1.4 EB05 1.3 · IC025 +0.3 | Not in label — unassessed | serious PRR 1.0 | no trial data cached |
| Lymphopenia | 230 | 36.5 32.1–41.5ROR 37.3 · χ² 7,771 / p <1e-300 | 35.8 EB05 32.1 · IC025 +4.8 3/3 methods agree | Labeled — boxed warning exact term | serious PRR 24.8 | no trial data cached |
| Febrile neutropenia | 215 | 7.1 6.3–8.2ROR 7.3 · χ² 1,130 / p 5e-248 | 7.0 EB05 6.3 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.5 · ♀ 39% (drug 70%) · 98% 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.
- Anaemia haemolytic autoimmune — n=22, PRR 59.0
- Acute myeloid leukaemia recurrent — n=30, PRR 31.3
- Cutaneous vasculitis — n=23, PRR 14.2
- Gastrointestinal toxicity — n=22, PRR 10.3
- Haematotoxicity — n=40, PRR 9.5
- Optic neuritis — n=39, PRR 9.4
- Rash maculo-papular — n=94, PRR 9.3
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 Cladribine?
In FDA FAERS, the most frequently co-reported reaction terms for Cladribine are fatigue, headache, lymphocyte count decreased, multiple sclerosis relapse, nausea, pneumonia. 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 Cladribine have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: MALIGNANCIES AND RISK OF TERATOGENICITY Malignancies Treatment with cladribine tablets may increase the risk of malignancy. Cladribine tablets are contraindicated in patients with current malignancy. In patients with.
Do FAERS signals prove that Cladribine 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 407c52d5-6498-7da5-da35-acc9ca73ced3, effective 20260608; matched on
openfda.generic_name.exact:"CLADRIBINE") - 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, 1,018 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.