Selumetinib side effects: what 1,518 FDA adverse event reports show
Brand names
Koselugo
Who reports
1,518 reports · 81% serious · 99 with death outcome · 49% female
Used for
KOSELUGO is indicated for the treatment of adult and pediatric patients 1 year of age and older with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN) . KOSELUGO is a kinase.
What it is
KOSELUGO contains selumetinib sulfate, a kinase inhibitor.
Boxed warning
None in the current label
Causality screen of the 19 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.
- 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. 4 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 |
|---|---|---|---|---|---|---|
| Blood creatine phosphokinase increased | 106 | 49.8 41.5–59.9ROR 53.5 · χ² 5,013 / p <1e-300 | 49.2 EB05 41.9 · IC025 +5.0 3/3 methods agree | Lab value / disease marker | serious PRR 36.4 | no trial data cached |
| Retinal detachment | 23 | 34.4 22.9–51.6ROR 34.9 · χ² 710 / p 8e-157 | 33.4 EB05 23.5 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 24.9 | no trial data cached |
| Neoplasm | 27 | 32.2 22.1–46.8ROR 32.7 · χ² 784 / p 1e-172 | 31.5 EB05 22.7 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 22.4 · 74% consumer | no trial data cached |
| Hair colour changes | 25 | 27.3 18.5–40.3ROR 27.7 · χ² 606 / p 4e-134 | 26.7 EB05 19.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Ejection fraction decreased | 27 | 23.8 16.4–34.6ROR 24.2 · χ² 567 / p 1e-125 | 23.4 EB05 16.9 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 16.0 | no trial data cached |
| Acne | 77 | 13.9 11.2–17.2ROR 14.5 · χ² 909 / p 6e-200 | 13.7 EB05 11.3 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 29.9 | no trial data cached |
| Neoplasm progression | 34 | 13.3 9.5–18.5ROR 13.6 · χ² 374 / p 1e-83 | 12.9 EB05 9.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.6 | no trial data cached |
| Mitral valve incompetence | 10 | 12.1 6.5–22.5ROR 12.2 · χ² 91 / p 7e-22 | 10.1 EB05 5.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Folliculitis | 9 | 11.9 6.2–22.9ROR 12.0 · χ² 80 / p 2e-19 | 9.6 EB05 4.7 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.8 | no trial data cached |
| Brain neoplasm | 6 | 9.0 4.0–19.9ROR 9.0 · χ² 35 / p 2e-9 | 6.1 EB05 2.8 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.5 | no trial data cached |
| Cytopenia | 7 | 8.0 3.8–16.8ROR 8.1 · χ² 36 / p 8e-10 | 5.7 EB05 2.9 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 | no trial data cached |
| Dermatitis | 12 | 7.9 4.5–14.0ROR 8.0 · χ² 66 / p 2e-16 | 6.4 EB05 3.8 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.7 | no trial data cached |
| Haematochezia (blood in stool) | 28 | 7.0 4.8–10.1ROR 7.1 · χ² 137 / p 5e-32 | 6.3 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · 75% consumer | no trial data cached |
| Blood lactate dehydrogenase increased | 8 | 6.9 3.4–13.7ROR 6.9 · χ² 35 / p 2e-9 | 5.2 EB05 2.8 · IC025 +1.1 3/3 methods agree | Lab value / disease marker | serious PRR 4.6 | no trial data cached |
| Mouth ulceration | 10 | 6.5 3.5–12.1ROR 6.6 · χ² 41 / p 6e-11 | 5.2 EB05 3.0 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Pharyngitis streptococcal | 5 | 6.3 2.6–15.2ROR 6.3 · χ² 17 / p 1e-5 | 4.3 EB05 2.0 · IC025 +0.5 3/3 methods agree | Not in label — unassessed | serious n=5 | no trial data cached |
| Eczema | 23 | 6.3 4.2–9.4ROR 6.3 · χ² 97 / p 4e-23 | 5.6 EB05 3.9 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.9 | no trial data cached |
| Rhabdomyolysis (muscle breakdown) | 15 | 4.9 3.0–8.2ROR 5.0 · χ² 43 / p 2e-11 | 4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.6 | no trial data cached |
| Dry skin | 38 | 4.0 2.9–5.4ROR 4.0 · χ² 82 / p 8e-20 | 3.8 EB05 2.9 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.4 | 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 |
|---|---|---|---|---|---|---|
| Blood creatine phosphokinase increased | 106 | 49.8 41.5–59.9ROR 53.5 · χ² 5,013 / p <1e-300 | 49.2 EB05 41.9 · IC025 +5.0 3/3 methods agree | Lab value / disease marker | serious PRR 36.4 | no trial data cached |
| Acne | 77 | 13.9 11.2–17.2ROR 14.5 · χ² 909 / p 6e-200 | 13.7 EB05 11.3 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 29.9 | no trial data cached |
| Dry skin | 38 | 4.0 2.9–5.4ROR 4.0 · χ² 82 / p 8e-20 | 3.8 EB05 2.9 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.4 | no trial data cached |
| Neoplasm progression | 34 | 13.3 9.5–18.5ROR 13.6 · χ² 374 / p 1e-83 | 12.9 EB05 9.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.6 | no trial data cached |
| Haematochezia (blood in stool) | 28 | 7.0 4.8–10.1ROR 7.1 · χ² 137 / p 5e-32 | 6.3 EB05 4.6 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · 75% consumer | no trial data cached |
| Ejection fraction decreased | 27 | 23.8 16.4–34.6ROR 24.2 · χ² 567 / p 1e-125 | 23.4 EB05 16.9 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 16.0 | no trial data cached |
| Neoplasm | 27 | 32.2 22.1–46.8ROR 32.7 · χ² 784 / p 1e-172 | 31.5 EB05 22.7 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 22.4 · 74% consumer | no trial data cached |
| Hair colour changes | 25 | 27.3 18.5–40.3ROR 27.7 · χ² 606 / p 4e-134 | 26.7 EB05 19.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Eczema | 23 | 6.3 4.2–9.4ROR 6.3 · χ² 97 / p 4e-23 | 5.6 EB05 3.9 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.9 | no trial data cached |
| Retinal detachment | 23 | 34.4 22.9–51.6ROR 34.9 · χ² 710 / p 8e-157 | 33.4 EB05 23.5 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 24.9 | no trial data cached |
| Rhabdomyolysis (muscle breakdown) | 15 | 4.9 3.0–8.2ROR 5.0 · χ² 43 / p 2e-11 | 4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.6 | no trial data cached |
| Dermatitis | 12 | 7.9 4.5–14.0ROR 8.0 · χ² 66 / p 2e-16 | 6.4 EB05 3.8 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.7 | no trial data cached |
| Mouth ulceration | 10 | 6.5 3.5–12.1ROR 6.6 · χ² 41 / p 6e-11 | 5.2 EB05 3.0 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Mitral valve incompetence | 10 | 12.1 6.5–22.5ROR 12.2 · χ² 91 / p 7e-22 | 10.1 EB05 5.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Folliculitis | 9 | 11.9 6.2–22.9ROR 12.0 · χ² 80 / p 2e-19 | 9.6 EB05 4.7 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.8 | 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.
- Neoplasm — n=27, PRR 32.2
- Hair colour changes — n=25, PRR 27.3
- Neoplasm progression — n=34, PRR 13.3
- Haematochezia — n=28, PRR 7.0
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 Selumetinib?
In FDA FAERS, the most frequently co-reported reaction terms for Selumetinib are blood creatine phosphokinase increased, acne, dry skin, neoplasm progression, haematochezia, ejection fraction decreased. 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 Selumetinib have an FDA boxed warning?
No. The FDA label retrieved for Selumetinib has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Selumetinib 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 7d042c61-f28f-4ab5-ab10-d7558c0d49ff, effective 20260526; matched on
openfda.generic_name.exact:"SELUMETINIB") - 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, 23 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.