Drug · FAERS side-effect profile with label screen

Nalxone side effects: what 918 FDA adverse event reports show

Nalxone Hydrochloride · 40 reaction terms · 627 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Label matched

Nalxone Hydrochloride (Naloxone Hydrochloride)

closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match

Who reports

918 reports · 81% serious · 137 with death outcome · 46% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Naloxone Hydrochloride Injection, USP is indicated for the complete or partial reversal of opioid depression, including respiratory depression, induced by natural and synthetic opioids, including propoxyphene, methadone, and certain mixed agonist-antagonist analgesics: nalbuphine, pentazocine, butorphanol, and cyclazocine.

FDA label, Indications and Usage

What it is

DESCRIPTION Naloxone Hydrochloride Injection, USP, an opioid antagonist, is a synthetic congener of oxymorphone. In structure it differs from oxymorphone in that the methyl group on the nitrogen atom is replaced by an allyl group.

FDA label, Description section

Boxed warning

None in the current 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 20 strongest signals

Labeled adverse reaction 1Labeled (related wording) 1Reporting / coding artifact 4Lab value / disease marker 1Not in label — unassessed 13

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.
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. 20 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
Transfusion	17	37.0 23.1–59.3ROR 37.7 · χ² 559 / p 7e-124	35.6 EB05 23.5 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 27.7	no trial data cached
Oral candidiasis (oral thrush)	17	29.9 18.7–47.9ROR 30.4 · χ² 446 / p 3e-99	29.0 EB05 19.1 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 29.9	no trial data cached
Unresponsive to stimuli	31	27.6 19.5–39.0ROR 28.5 · χ² 767 / p 4e-169	27.1 EB05 20.0 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 20.1 · ♀ 23% (drug 46%)	no trial data cached
Premature delivery	18	25.7 16.3–40.7ROR 26.2 · χ² 403 / p 5e-90	25.1 EB05 16.7 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 18.8	no trial data cached
Caesarean section	11	21.4 11.9–38.5ROR 21.6 · χ² 194 / p 2e-44	20.4 EB05 11.6 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious PRR 15.7	no trial data cached
Joint range of motion decreased	10	17.1 9.2–31.7ROR 17.3 · χ² 136 / p 1e-31	15.7 EB05 7.9 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 15.6	no trial data cached
Drug withdrawal syndrome neonatal	11	16.8 9.3–30.3ROR 17.0 · χ² 148 / p 2e-34	15.6 EB05 8.3 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Haematocrit decreased	13	14.9 8.7–25.5ROR 15.1 · χ² 155 / p 8e-36	13.7 EB05 7.7 · IC025 +2.4 3/3 methods agree	Lab value / disease marker	serious PRR 12.0	no trial data cached
Syringe issue	10	13.0 7.0–24.2ROR 13.2 · χ² 99 / p 1e-23	11.1 EB05 5.6 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious n=1	no trial data cached
Head discomfort	10	13.0 7.0–24.0ROR 13.1 · χ² 99 / p 1e-23	11.0 EB05 5.5 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 16.5	no trial data cached
Premature baby	17	12.9 8.0–20.6ROR 13.1 · χ² 175 / p 4e-40	11.9 EB05 7.3 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 9.3	no trial data cached
Feeling cold	15	12.3 7.4–20.3ROR 12.5 · χ² 145 / p 1e-33	11.1 EB05 6.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 11.8	no trial data cached
Pulmonary oedema	24	12.2 8.2–18.2ROR 12.5 · χ² 237 / p 9e-54	11.6 EB05 7.8 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.9 · 100% clinician	no trial data cached
Drug withdrawal syndrome	46	11.9 8.9–15.7ROR 12.4 · χ² 448 / p 1e-99	11.5 EB05 8.8 · IC025 +2.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.5	no trial data cached
Toxicity to various agents	82	11.2 9.1–13.7ROR 12.2 · χ² 754 / p 2e-166	11.0 EB05 9.1 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.1	no trial data cached
Febrile neutropenia	32	11.0 7.9–15.5ROR 11.4 · χ² 283 / p 8e-64	10.5 EB05 7.5 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 7.9	no trial data cached
Drug abuse	30	8.2 5.8–11.7ROR 8.4 · χ² 183 / p 5e-42	7.5 EB05 5.4 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious PRR 5.9 · ♀ 70% (drug 46%)	no trial data cached
Foetal exposure during pregnancy	20	5.6 3.6–8.7ROR 5.7 · χ² 72 / p 1e-17	5.0 EB05 3.4 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious PRR 4.1	no trial data cached
Overdose	46	4.9 3.7–6.4ROR 5.1 · χ² 138 / p 3e-32	4.6 EB05 3.6 · IC025 +1.7 3/3 methods agree	Reporting / coding artifact	serious PRR 4.3	no trial data cached
Drug dependence	30	4.2 3.0–6.0ROR 4.3 · χ² 71 / p 2e-17	4.0 EB05 2.9 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 3.0 · ♀ 77% (drug 46%)	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
Toxicity to various agents	82	11.2 9.1–13.7ROR 12.2 · χ² 754 / p 2e-166	11.0 EB05 9.1 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.1	no trial data cached
Overdose	46	4.9 3.7–6.4ROR 5.1 · χ² 138 / p 3e-32	4.6 EB05 3.6 · IC025 +1.7 3/3 methods agree	Reporting / coding artifact	serious PRR 4.3	no trial data cached
Drug withdrawal syndrome	46	11.9 8.9–15.7ROR 12.4 · χ² 448 / p 1e-99	11.5 EB05 8.8 · IC025 +2.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.5	no trial data cached
Febrile neutropenia	32	11.0 7.9–15.5ROR 11.4 · χ² 283 / p 8e-64	10.5 EB05 7.5 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 7.9	no trial data cached
Unresponsive to stimuli	31	27.6 19.5–39.0ROR 28.5 · χ² 767 / p 4e-169	27.1 EB05 20.0 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 20.1 · ♀ 23% (drug 46%)	no trial data cached
Drug dependence	30	4.2 3.0–6.0ROR 4.3 · χ² 71 / p 2e-17	4.0 EB05 2.9 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 3.0 · ♀ 77% (drug 46%)	no trial data cached
Drug abuse	30	8.2 5.8–11.7ROR 8.4 · χ² 183 / p 5e-42	7.5 EB05 5.4 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious PRR 5.9 · ♀ 70% (drug 46%)	no trial data cached
Pulmonary oedema	24	12.2 8.2–18.2ROR 12.5 · χ² 237 / p 9e-54	11.6 EB05 7.8 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.9 · 100% clinician	no trial data cached
Foetal exposure during pregnancy	20	5.6 3.6–8.7ROR 5.7 · χ² 72 / p 1e-17	5.0 EB05 3.4 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious PRR 4.1	no trial data cached
Premature delivery	18	25.7 16.3–40.7ROR 26.2 · χ² 403 / p 5e-90	25.1 EB05 16.7 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 18.8	no trial data cached
Premature baby	17	12.9 8.0–20.6ROR 13.1 · χ² 175 / p 4e-40	11.9 EB05 7.3 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 9.3	no trial data cached
Oral candidiasis (oral thrush)	17	29.9 18.7–47.9ROR 30.4 · χ² 446 / p 3e-99	29.0 EB05 19.1 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 29.9	no trial data cached
Transfusion	17	37.0 23.1–59.3ROR 37.7 · χ² 559 / p 7e-124	35.6 EB05 23.5 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 27.7	no trial data cached
Feeling cold	15	12.3 7.4–20.3ROR 12.5 · χ² 145 / p 1e-33	11.1 EB05 6.5 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 11.8	no trial data cached
Haematocrit decreased	13	14.9 8.7–25.5ROR 15.1 · χ² 155 / p 8e-36	13.7 EB05 7.7 · IC025 +2.4 3/3 methods agree	Lab value / disease marker	serious PRR 12.0	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.

Unresponsive to stimuli — n=31, PRR 27.6
Toxicity to various agents — n=82, PRR 11.2
Febrile neutropenia — n=32, PRR 11.0

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 Nalxone?

In FDA FAERS, the most frequently co-reported reaction terms for Nalxone are toxicity to various agents, drug withdrawal syndrome, febrile neutropenia, unresponsive to stimuli, pulmonary oedema, premature delivery. 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 Nalxone have an FDA boxed warning?

No. The FDA label retrieved for Nalxone has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Nalxone 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 1bef59b9-7d51-4f19-a054-44b8eb6c6398, effective 20240410; matched on openfda.generic_name.exact:"NALXONE 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, field patient.drug.openfda.generic_name.exact, 40 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.