Drug · FAERS side-effect profile with label screen
Naltrexone Hydrochloride side effects: what 1,483 FDA adverse event reports show
Drug class
Not stated in label
Who reports
1,483 reports · 64% serious · 80 with death outcome · 70% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Treatment with naltrexone for extended-release injectable suspension should be part of a comprehensive management program that includes psychosocial support. Naltrexone for extended-release injectable suspension contains naltrexone, an opioid antagonis.
FDA label, Indications and Usage
What it is
Naltrexone for extended-release injectable suspension is supplied as a microsphere formulation of naltrexone for suspension, to be administered by deep intramuscular injection by a healthcare practitioner.
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 40 strongest signals
Labeled adverse reaction 6Labeled (related wording) 10Reporting / coding artifact 3Lab value / disease marker 4Outcome field, not a reaction 1Not in label — unassessed 16
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.
- Outcome field, not a reaction Death is a report outcome, not a reaction term. It is dominated by the underlying illness; see the seriousness profile and the boxed warning instead.
- 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. 39 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 |
|---|---|---|---|---|---|---|
| Hyperlipidaemia | 53 | 62.8 48.1–81.8ROR 65.0 · χ² 3,147 / p <1e-300 | 61.2 EB05 48.6 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 62.2 · ♀ 100% (drug 70%) · 96% clinician | no trial data cached |
| Impaired quality of life | 62 | 61.1 47.9–78.1ROR 63.8 · χ² 3,595 / p <1e-300 | 59.8 EB05 48.3 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 77.8 · ♀ 100% (drug 70%) · 98% clinician | no trial data cached |
| Poor quality sleep | 71 | 47.0 37.5–59.0ROR 49.3 · χ² 3,146 / p <1e-300 | 46.3 EB05 38.0 · IC025 +4.8 3/3 methods agree | Reporting / coding artifact | serious PRR 75.9 · ♀ 100% (drug 70%) · 93% clinician | no trial data cached |
| Impaired work ability | 60 | 39.6 30.9–50.8ROR 41.3 · χ² 2,217 / p <1e-300 | 39.1 EB05 31.5 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 45.0 · ♀ 98% (drug 70%) · 98% clinician | no trial data cached |
| Oral herpes | 53 | 38.6 29.6–50.3ROR 40.0 · χ² 1,901 / p <1e-300 | 38.0 EB05 30.2 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 78.6 · ♀ 98% (drug 70%) · 91% clinician | no trial data cached |
| Skin disorder | 55 | 23.4 18.0–30.3ROR 24.3 · χ² 1,156 / p 9e-254 | 23.2 EB05 18.5 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 35.1 · ♀ 98% (drug 70%) | no trial data cached |
| Bone density decreased | 50 | 22.3 17.0–29.3ROR 23.1 · χ² 998 / p 3e-219 | 22.1 EB05 17.4 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious PRR 25.2 · ♀ 100% (drug 70%) · 96% clinician | no trial data cached |
| Serotonin syndrome | 26 | 19.2 13.1–28.2ROR 19.6 · χ² 431 / p 5e-96 | 18.9 EB05 13.5 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 16.8 | no trial data cached |
| Insurance issue | 17 | 16.2 10.1–26.0ROR 16.4 · χ² 227 / p 1e-51 | 15.5 EB05 9.8 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 28.4 | no trial data cached |
| Cellulitis (skin infection) | 57 | 16.0 12.4–20.6ROR 16.6 · χ² 787 / p 2e-173 | 15.8 EB05 12.6 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 15.7 · ♀ 98% (drug 70%) | no trial data cached |
| Herpes zoster (shingles) | 60 | 14.7 11.5–18.9ROR 15.3 · χ² 756 / p 9e-167 | 14.6 EB05 11.7 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 20.1 · ♀ 94% (drug 70%) · 93% clinician | no trial data cached |
| Infusion site pain | 13 | 14.4 8.4–24.7ROR 14.5 · χ² 149 / p 2e-34 | 13.2 EB05 7.4 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious n=8 | no trial data cached |
| Cataract | 58 | 13.8 10.7–17.8ROR 14.4 · χ² 679 / p 6e-150 | 13.7 EB05 10.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 · ♀ 98% (drug 70%) | no trial data cached |
| Blood triglycerides increased | 16 | 12.8 7.8–20.8ROR 12.9 · χ² 162 / p 2e-37 | 11.7 EB05 7.0 · IC025 +2.4 3/3 methods agree | Lab value / disease marker | serious PRR 17.0 | no trial data cached |
| Joint range of motion decreased | 12 | 12.7 7.2–22.3ROR 12.8 · χ² 118 / p 1e-27 | 11.1 EB05 6.0 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 14.6 | no trial data cached |
| Dermatitis contact | 10 | 12.5 6.7–23.1ROR 12.5 · χ² 94 / p 1e-22 | 10.4 EB05 5.3 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=7 | no trial data cached |
| Thinking abnormal | 16 | 12.1 7.4–19.7ROR 12.2 · χ² 152 / p 4e-35 | 10.9 EB05 6.6 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 14.9 | no trial data cached |
| Musculoskeletal chest pain | 13 | 11.9 6.9–20.4ROR 12.0 · χ² 119 / p 6e-28 | 10.3 EB05 5.8 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.9 | no trial data cached |
| Viral infection | 26 | 11.1 7.6–16.2ROR 11.2 · χ² 228 / p 8e-52 | 10.3 EB05 7.1 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.4 | no trial data cached |
| Blood glucose abnormal | 13 | 9.9 5.8–17.1ROR 10.0 · χ² 96 / p 7e-23 | 8.3 EB05 4.8 · IC025 +2.0 3/3 methods agree | Lab value / disease marker | serious PRR 19.2 | no trial data cached |
| Head injury | 21 | 9.4 6.1–14.4ROR 9.5 · χ² 150 / p 1e-34 | 8.4 EB05 5.6 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 8.9 | no trial data cached |
| Contusion | 62 | 9.1 7.1–11.6ROR 9.5 · χ² 442 / p 2e-98 | 8.8 EB05 7.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 14.3 · ♀ 98% (drug 70%) | no trial data cached |
| Gastroenteritis viral | 11 | 8.6 4.8–15.5ROR 8.6 · χ² 66 / p 2e-16 | 6.8 EB05 3.9 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.7 | no trial data cached |
| Panic attack | 21 | 8.1 5.3–12.4ROR 8.2 · χ² 125 / p 3e-29 | 7.2 EB05 4.9 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.6 | no trial data cached |
| Rhabdomyolysis (muscle breakdown) | 23 | 7.8 5.2–11.7ROR 7.9 · χ² 130 / p 2e-30 | 7.0 EB05 4.8 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 · 100% clinician | no trial data cached |
| Blood pressure systolic increased | 10 | 7.2 3.9–13.4ROR 7.3 · χ² 48 / p 3e-12 | 5.7 EB05 3.2 · IC025 +1.4 3/3 methods agree | Lab value / disease marker | serious PRR 7.1 | no trial data cached |
| Pancreatitis acute | 11 | 7.0 3.9–12.6ROR 7.0 · χ² 50 / p 6e-13 | 5.6 EB05 3.3 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.3 | no trial data cached |
| Illness | 47 | 6.6 5.0–8.8ROR 6.8 · χ² 219 / p 7e-50 | 6.2 EB05 4.9 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 8.1 · 83% consumer | no trial data cached |
| Injection site mass | 17 | 6.5 4.1–10.5ROR 6.6 · χ² 74 / p 4e-18 | 5.6 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 20.3 | no trial data cached |
| Frequent bowel movements | 12 | 6.3 3.6–11.1ROR 6.3 · χ² 48 / p 2e-12 | 5.2 EB05 3.2 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.8 | no trial data cached |
| Pallor | 12 | 6.2 3.5–10.9ROR 6.3 · χ² 47 / p 3e-12 | 5.1 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Contraindicated product administered | 13 | 6.1 3.5–10.5ROR 6.1 · χ² 50 / p 6e-13 | 5.1 EB05 3.2 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 6.9 | no trial data cached |
| Withdrawal syndrome | 18 | 6.0 3.8–9.5ROR 6.1 · χ² 71 / p 2e-17 | 5.3 EB05 3.5 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.5 | no trial data cached |
| Drug reaction with eosinophilia and systemic symptoms | 10 | 5.5 3.0–10.3ROR 5.6 · χ² 33 / p 5e-9 | 4.5 EB05 2.6 · IC025 +1.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.0 | no trial data cached |
| Coma | 18 | 5.3 3.4–8.4ROR 5.4 · χ² 59 / p 7e-15 | 4.7 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Eye pruritus | 12 | 5.1 2.9–9.0ROR 5.2 · χ² 36 / p 1e-9 | 4.4 EB05 2.7 · IC025 +1.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.2 | no trial data cached |
| Suicidal ideation (thoughts of suicide) | 31 | 4.8 3.4–6.8ROR 4.9 · χ² 89 / p 2e-21 | 4.5 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.3 | no trial data cached |
| Colitis ulcerative | 15 | 4.8 2.9–7.9ROR 4.8 · χ² 41 / p 8e-11 | 4.2 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | no trial data cached |
| Abnormal behaviour | 13 | 4.6 2.7–7.9ROR 4.6 · χ² 33 / p 4e-9 | 4.0 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | no trial data cached |
| Completed suicide (death by suicide) | 23 | 3.9 2.6–5.8ROR 3.9 · χ² 46 / p 5e-12 | 3.6 EB05 2.6 · IC025 +1.2 3/3 methods agree | Outcome field, not a reaction | serious PRR 3.5 | 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 |
|---|---|---|---|---|---|---|
| Poor quality sleep | 71 | 47.0 37.5–59.0ROR 49.3 · χ² 3,146 / p <1e-300 | 46.3 EB05 38.0 · IC025 +4.8 3/3 methods agree | Reporting / coding artifact | serious PRR 75.9 · ♀ 100% (drug 70%) · 93% clinician | no trial data cached |
| Contusion | 62 | 9.1 7.1–11.6ROR 9.5 · χ² 442 / p 2e-98 | 8.8 EB05 7.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 14.3 · ♀ 98% (drug 70%) | no trial data cached |
| Impaired quality of life | 62 | 61.1 47.9–78.1ROR 63.8 · χ² 3,595 / p <1e-300 | 59.8 EB05 48.3 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 77.8 · ♀ 100% (drug 70%) · 98% clinician | no trial data cached |
| Herpes zoster (shingles) | 60 | 14.7 11.5–18.9ROR 15.3 · χ² 756 / p 9e-167 | 14.6 EB05 11.7 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 20.1 · ♀ 94% (drug 70%) · 93% clinician | no trial data cached |
| Impaired work ability | 60 | 39.6 30.9–50.8ROR 41.3 · χ² 2,217 / p <1e-300 | 39.1 EB05 31.5 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 45.0 · ♀ 98% (drug 70%) · 98% clinician | no trial data cached |
| Cataract | 58 | 13.8 10.7–17.8ROR 14.4 · χ² 679 / p 6e-150 | 13.7 EB05 10.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 · ♀ 98% (drug 70%) | no trial data cached |
| Cellulitis (skin infection) | 57 | 16.0 12.4–20.6ROR 16.6 · χ² 787 / p 2e-173 | 15.8 EB05 12.6 · IC025 +3.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 15.7 · ♀ 98% (drug 70%) | no trial data cached |
| Skin disorder | 55 | 23.4 18.0–30.3ROR 24.3 · χ² 1,156 / p 9e-254 | 23.2 EB05 18.5 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 35.1 · ♀ 98% (drug 70%) | no trial data cached |
| Oral herpes | 53 | 38.6 29.6–50.3ROR 40.0 · χ² 1,901 / p <1e-300 | 38.0 EB05 30.2 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 78.6 · ♀ 98% (drug 70%) · 91% clinician | no trial data cached |
| Hyperlipidaemia | 53 | 62.8 48.1–81.8ROR 65.0 · χ² 3,147 / p <1e-300 | 61.2 EB05 48.6 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 62.2 · ♀ 100% (drug 70%) · 96% clinician | no trial data cached |
| Bone density decreased | 50 | 22.3 17.0–29.3ROR 23.1 · χ² 998 / p 3e-219 | 22.1 EB05 17.4 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious PRR 25.2 · ♀ 100% (drug 70%) · 96% clinician | no trial data cached |
| Illness | 47 | 6.6 5.0–8.8ROR 6.8 · χ² 219 / p 7e-50 | 6.2 EB05 4.9 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 8.1 · 83% consumer | no trial data cached |
| Injection site pain (pain where injected) | 35 | 1.6 1.2–2.3ROR 1.6 · χ² 8 / p 0.002 | 1.6 EB05 1.2 · IC025 +0.1 | Labeled adverse reaction exact term | serious PRR 2.2 | no trial data cached |
| Suicidal ideation (thoughts of suicide) | 31 | 4.8 3.4–6.8ROR 4.9 · χ² 89 / p 2e-21 | 4.5 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.3 | no trial data cached |
| Viral infection | 26 | 11.1 7.6–16.2ROR 11.2 · χ² 228 / p 8e-52 | 10.3 EB05 7.1 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.4 | 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.
- Hyperlipidaemia — n=53, PRR 62.8
- Impaired quality of life — n=62, PRR 61.1
- Impaired work ability — n=60, PRR 39.6
- Oral herpes — n=53, PRR 38.6
- Serotonin syndrome — n=26, PRR 19.2
- Herpes zoster — n=60, PRR 14.7
- Cataract — n=58, PRR 13.8
- Contusion — n=62, PRR 9.1
- Rhabdomyolysis — n=23, PRR 7.8
✓ A hand-written Bradford Hill causality assessment exists for this drug: Naltrexone ↔ Drug withdrawal syndrome.
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 Naltrexone?
In FDA FAERS, the most frequently co-reported reaction terms for Naltrexone are contusion, impaired quality of life, herpes zoster, impaired work ability, cataract, cellulitis. 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 Naltrexone have an FDA boxed warning?
No. The FDA label retrieved for Naltrexone has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Naltrexone 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 6de5637f-d527-4228-af1a-3aae71155cb5, effective 20260130; matched on
openfda.generic_name.exact:"NALTREXONE") - 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, 79 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.