Arsenic Trioxide side effects: what 1,138 FDA adverse event reports show

Arsenic Trioxide · 97 reaction terms · 2,410 drug–reaction co-reports · data 2026-09-14

Drug class

Arsenical

FDA label, Indications wording

Who reports

1,138 reports · 98% serious · 145 with death outcome · 50% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Arsenic trioxide injection is an arsenical indicated: In combination with tretinoin for treatment of adults with newly-diagnosed low-risk acute promyelocytic leukemia (APL) whose APL is characterized by the presence of the t(15;17) translocation or PML/RAR-alpha gene expression.

FDA label, Indications and Usage

What it is

Arsenic trioxide injection is a sterile injectable solution of arsenic trioxide.

FDA label, Description section

Boxed warning

DIFFERENTIATION SYNDROME, CARDIAC CONDUCTION ABNORMALITIES AND ENCEPHALOPATHY INCLUDING WERNICKE'S Differentiation Syndrome: Patients with acute promyelocytic leukemia (APL) treated with arsenic trioxide have experienced differentiation syndrome, which may be life-threatening or fatal.

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 3Labeled adverse reaction 10Labeled (related wording) 5Likely indication confounding 1Lab value / disease marker 3Not in label — unassessed 18

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.
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. 57 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Electrocardiogram qt prolonged	261	67.4 60.1–75.6ROR 76.0 · χ² 16,914 / p <1e-300	66.6 EB05 60.1 · IC025 +5.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 34.1 · 96% clinician	no trial data cached
Disseminated intravascular coagulation	50	32.8 24.9–43.2ROR 33.5 · χ² 1,505 / p <1e-300	32.3 EB05 25.5 · IC025 +4.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.1	no trial data cached
Leukocytosis	47	24.0 18.1–31.9ROR 24.5 · χ² 1,014 / p 1e-222	23.8 EB05 18.6 · IC025 +3.8 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 12.9	no trial data cached
Pericardial effusion	58	23.3 18.1–30.1ROR 23.9 · χ² 1,215 / p 2e-266	23.1 EB05 18.5 · IC025 +3.9 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 10.0	no trial data cached
Pericarditis	38	21.1 15.4–28.9ROR 21.4 · χ² 706 / p 7e-156	20.8 EB05 15.8 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious PRR 16.4 · 100% clinician	no trial data cached
Acute myeloid leukaemia	33	19.6 14.0–27.5ROR 19.9 · χ² 563 / p 9e-125	19.3 EB05 14.4 · IC025 +3.4 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 14.7	no trial data cached
Hypomagnesaemia	25	16.7 11.3–24.6ROR 16.8 · χ² 352 / p 8e-79	16.3 EB05 11.4 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.7	no trial data cached
Ventricular extrasystoles	18	16.0 10.1–25.4ROR 16.1 · χ² 238 / p 5e-54	15.4 EB05 9.8 · IC025 +2.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.5	no trial data cached
Blood lactate dehydrogenase increased	24	13.9 9.3–20.7ROR 14.0 · χ² 275 / p 6e-62	13.4 EB05 9.1 · IC025 +2.8 3/3 methods agree	Lab value / disease marker	serious PRR 3.6	no trial data cached
Gamma-glutamyltransferase increased	33	13.7 9.8–19.3ROR 13.9 · χ² 377 / p 2e-84	13.4 EB05 9.8 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.6	no trial data cached
Mitral valve incompetence	16	13.1 8.0–21.3ROR 13.1 · χ² 166 / p 2e-38	12.0 EB05 7.2 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.9	no trial data cached
Myocarditis	16	13.1 8.0–21.3ROR 13.1 · χ² 166 / p 3e-38	12.0 EB05 7.2 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 11.5	no trial data cached
Hypokalaemia (low potassium)	60	12.1 9.4–15.5ROR 12.4 · χ² 599 / p 1e-132	11.8 EB05 9.4 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.8 · ♀ 14% (drug 50%) · 100% clinician	no trial data cached
Hypercalcaemia	16	12.0 7.4–19.5ROR 12.1 · χ² 150 / p 8e-35	10.8 EB05 6.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 3.8	no trial data cached
Alanine aminotransferase increased	79	11.9 9.6–14.8ROR 12.3 · χ² 778 / p 2e-171	11.7 EB05 9.6 · IC025 +3.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 1.8	no trial data cached
Lymphopenia	18	11.8 7.5–18.7ROR 11.9 · χ² 168 / p 1e-38	10.8 EB05 6.7 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 13.4	no trial data cached
Myoclonus	15	11.6 7.0–19.3ROR 11.7 · χ² 135 / p 2e-31	10.3 EB05 6.1 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 13.5	no trial data cached
White blood cell count increased	48	11.5 8.7–15.2ROR 11.7 · χ² 451 / p 2e-100	11.2 EB05 8.6 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious PRR 10.5 · ♀ 25% (drug 50%) · 100% clinician	no trial data cached
Hepatic function abnormal	46	11.5 8.6–15.3ROR 11.7 · χ² 429 / p 1e-95	11.1 EB05 8.5 · IC025 +2.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 1.3	no trial data cached
Aspartate aminotransferase increased	65	11.3 8.9–14.4ROR 11.6 · χ² 601 / p 4e-133	11.1 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 2.1	no trial data cached
Hepatotoxicity (liver damage)	27	11.3 7.7–16.4ROR 11.4 · χ² 242 / p 7e-55	10.6 EB05 7.3 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.5	no trial data cached
Pleural effusion	74	11.2 9.0–14.0ROR 11.6 · χ² 680 / p 3e-150	11.0 EB05 9.0 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.4	no trial data cached
Neurotoxicity	21	11.2 7.3–17.1ROR 11.3 · χ² 184 / p 3e-42	10.3 EB05 6.7 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.0	no trial data cached
Ventricular tachycardia	20	11.1 7.2–17.3ROR 11.2 · χ² 175 / p 3e-40	10.2 EB05 6.6 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.0	no trial data cached
Vasculitis	14	11.1 6.6–18.7ROR 11.2 · χ² 119 / p 6e-28	9.6 EB05 5.6 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 2.0	no trial data cached
Febrile neutropenia	79	11.0 8.9–13.7ROR 11.4 · χ² 711 / p 5e-157	10.8 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.1 · 94% clinician	no trial data cached
Blood alkaline phosphatase increased	29	10.8 7.5–15.5ROR 10.9 · χ² 247 / p 5e-56	10.1 EB05 7.1 · IC025 +2.6 3/3 methods agree	Lab value / disease marker	serious PRR 3.0	no trial data cached
Mucosal inflammation	30	10.6 7.5–15.2ROR 10.8 · χ² 252 / p 4e-57	10.0 EB05 7.1 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 6.2	no trial data cached
Pancytopenia (all blood cells low)	59	9.8 7.6–12.6ROR 10.0 · χ² 457 / p 1e-101	9.4 EB05 7.5 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.4	no trial data cached
Acute respiratory distress syndrome	18	9.4 5.9–14.9ROR 9.5 · χ² 127 / p 1e-29	8.2 EB05 5.3 · IC025 +2.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.2	no trial data cached
Subarachnoid haemorrhage	10	9.0 4.9–16.8ROR 9.1 · χ² 64 / p 7e-16	7.1 EB05 3.9 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 9.6	no trial data cached
Cardiomegaly	11	8.2 4.5–14.8ROR 8.2 · χ² 62 / p 1e-15	6.5 EB05 3.8 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 2.7	no trial data cached
Cardiomyopathy	13	8.1 4.7–14.0ROR 8.2 · χ² 74 / p 4e-18	6.7 EB05 4.0 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 3.0	no trial data cached
Hypoxia (low oxygen)	30	7.9 5.5–11.3ROR 8.0 · χ² 174 / p 5e-40	7.2 EB05 5.2 · IC025 +2.2 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 3.8	no trial data cached
Bacteraemia	10	7.8 4.2–14.6ROR 7.9 · χ² 53 / p 2e-13	6.1 EB05 3.5 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 3.7	no trial data cached
Drug reaction with eosinophilia and systemic symptoms	21	7.6 5.0–11.6ROR 7.7 · χ² 114 / p 8e-27	6.7 EB05 4.5 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Hepatic cytolysis	10	7.6 4.1–14.0ROR 7.6 · χ² 51 / p 6e-13	5.9 EB05 3.4 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 0.9	no trial data cached
Fluid overload	12	7.5 4.3–13.2ROR 7.5 · χ² 61 / p 2e-15	6.1 EB05 3.6 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 2.9	no trial data cached
Haemorrhage intracranial	12	7.4 4.2–13.0ROR 7.4 · χ² 60 / p 5e-15	6.0 EB05 3.6 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.4	no trial data cached
Staphylococcal infection	24	6.7 4.5–10.0ROR 6.8 · χ² 111 / p 3e-26	6.0 EB05 4.2 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 0.7	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
Electrocardiogram qt prolonged	261	67.4 60.1–75.6ROR 76.0 · χ² 16,914 / p <1e-300	66.6 EB05 60.1 · IC025 +5.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 34.1 · 96% clinician	no trial data cached
Febrile neutropenia	79	11.0 8.9–13.7ROR 11.4 · χ² 711 / p 5e-157	10.8 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.1 · 94% clinician	no trial data cached
Alanine aminotransferase increased	79	11.9 9.6–14.8ROR 12.3 · χ² 778 / p 2e-171	11.7 EB05 9.6 · IC025 +3.1 3/3 methods agree	Labeled (related wording) related wording	serious PRR 1.8	no trial data cached
Pleural effusion	74	11.2 9.0–14.0ROR 11.6 · χ² 680 / p 3e-150	11.0 EB05 9.0 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.4	no trial data cached
Neutropenia (low neutrophils (infection-fighting cells))	72	4.9 3.9–6.2ROR 5.0 · χ² 221 / p 2e-50	4.8 EB05 3.9 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.8 · 100% clinician	no trial data cached
White blood cell count decreased	72	6.1 4.9–7.7ROR 6.3 · χ² 305 / p 1e-68	5.9 EB05 4.8 · IC025 +2.2 3/3 methods agree	Labeled (related wording) related wording	serious PRR 1.8	no trial data cached
Aspartate aminotransferase increased	65	11.3 8.9–14.4ROR 11.6 · χ² 601 / p 4e-133	11.1 EB05 8.9 · IC025 +3.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 2.1	no trial data cached
Hypokalaemia (low potassium)	60	12.1 9.4–15.5ROR 12.4 · χ² 599 / p 1e-132	11.8 EB05 9.4 · IC025 +3.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.8 · ♀ 14% (drug 50%) · 100% clinician	no trial data cached
Pancytopenia (all blood cells low)	59	9.8 7.6–12.6ROR 10.0 · χ² 457 / p 1e-101	9.4 EB05 7.5 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.4	no trial data cached
Pericardial effusion	58	23.3 18.1–30.1ROR 23.9 · χ² 1,215 / p 2e-266	23.1 EB05 18.5 · IC025 +3.9 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 10.0	no trial data cached
Thrombocytopenia (low platelets)	56	4.6 3.6–6.0ROR 4.7 · χ² 157 / p 3e-36	4.5 EB05 3.6 · IC025 +1.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.5 · ♀ 26% (drug 50%) · 97% clinician	no trial data cached
Platelet count decreased	50	4.3 3.3–5.7ROR 4.4 · χ² 125 / p 2e-29	4.2 EB05 3.3 · IC025 +1.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 1.4	no trial data cached
Disseminated intravascular coagulation	50	32.8 24.9–43.2ROR 33.5 · χ² 1,505 / p <1e-300	32.3 EB05 25.5 · IC025 +4.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.1	no trial data cached
Respiratory failure	48	6.1 4.6–8.0ROR 6.2 · χ² 199 / p 2e-45	5.8 EB05 4.5 · IC025 +2.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 4.3 · ♀ 71% (drug 50%) · 100% clinician	no trial data cached
White blood cell count increased	48	11.5 8.7–15.2ROR 11.7 · χ² 451 / p 2e-100	11.2 EB05 8.6 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious PRR 10.5 · ♀ 25% (drug 50%) · 100% 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.

Pericarditis — n=38, PRR 21.1
Hypomagnesaemia — n=25, PRR 16.7
Mucosal inflammation — n=30, PRR 10.6
Drug reaction with eosinophilia and systemic symptoms — n=21, PRR 7.6
Staphylococcal infection — n=24, PRR 6.7

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 Arsenic Trioxide?

In FDA FAERS, the most frequently co-reported reaction terms for Arsenic Trioxide are electrocardiogram qt prolonged, febrile neutropenia, alanine aminotransferase increased, pleural effusion, neutropenia, white blood cell count 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 Arsenic Trioxide have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: DIFFERENTIATION SYNDROME, CARDIAC CONDUCTION ABNORMALITIES AND ENCEPHALOPATHY INCLUDING WERNICKE'S Differentiation Syndrome: Patients with acute promyelocytic leukemia (APL) treated with arsenic trioxide have experienced differentiation syndrome, which may be life-threatening or fatal.

Do FAERS signals prove that Arsenic Trioxide 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 2a999752-f350-4eff-97e7-e7106dfa85b5, effective 20250630; matched on openfda.generic_name.exact:"ARSENIC TRIOXIDE")
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, field patient.drug.openfda.generic_name.exact, 97 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.