Drug · FAERS side-effect profile with label screen
Acetaminophen side effects: what 49,708 FDA adverse event reports show
Drug class
Not stated in label
Who reports
49,708 reports · 46% serious · 2,236 with death outcome · 68% female
openFDA FAERS counts, all years, deduplication not applied
Used for
temporarily relieves minor aches and pains due to: headache muscular aches backache minor pain of arthritis the common cold toothache premenstrual and menstrual cramps temporarily reduces fever
FDA label, Indications and Usage
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
Likely indication confounding 1Reporting / coding artifact 2Not in label — unassessed 37
What the badges mean
- 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.
- 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. 1,135 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 |
|---|---|---|---|---|---|---|
| Nasal discomfort | 384 | 21.3 19.2–23.6ROR 21.5 · χ² 7,055 / p <1e-300 | 20.3 EB05 18.7 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=50 · 93% consumer | no trial arm names this drug |
| Nasal ulcer | 73 | 20.1 15.9–25.4ROR 20.1 · χ² 1,245 / p 4e-273 | 19.1 EB05 15.7 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | 100% consumer | no trial arm names this drug |
| Product package associated injury | 81 | 16.0 12.8–19.9ROR 16.0 · χ² 1,079 / p 5e-237 | 15.3 EB05 12.7 · IC025 +3.5 3/3 methods agree | Reporting / coding artifact | 100% consumer | no trial arm names this drug |
| Rhinitis allergic | 153 | 15.0 12.8–17.6ROR 15.1 · χ² 1,918 / p <1e-300 | 14.5 EB05 12.6 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=124 | no trial arm names this drug |
| Acute sinusitis | 59 | 14.9 11.5–19.4ROR 15.0 · χ² 727 / p 2e-160 | 14.3 EB05 11.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=48 | no trial arm names this drug |
| Chronic kidney disease-mineral and bone disorder | 36 | 14.6 10.4–20.3ROR 14.6 · χ² 426 / p 5e-95 | 13.8 EB05 10.3 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=36 · ♀ 0% (drug 68%) | no trial arm names this drug |
| Chronic sinusitis | 115 | 13.3 11.1–16.0ROR 13.4 · χ² 1,258 / p 6e-276 | 12.9 EB05 11.0 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=95 | no trial arm names this drug |
| Rhinalgia | 82 | 13.0 10.5–16.2ROR 13.0 · χ² 870 / p 1e-191 | 12.5 EB05 10.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | 83% consumer | no trial arm names this drug |
| Infective pulmonary exacerbation of cystic fibrosis | 162 | 12.8 11.0–15.0ROR 12.8 · χ² 1,700 / p <1e-300 | 12.4 EB05 10.8 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=150 | no trial arm names this drug |
| Nasal dryness | 176 | 12.2 10.5–14.1ROR 12.2 · χ² 1,740 / p <1e-300 | 11.8 EB05 10.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=28 · 89% consumer | no trial arm names this drug |
| Nephrogenic anaemia | 129 | 11.9 10.0–14.2ROR 12.0 · χ² 1,247 / p 2e-273 | 11.5 EB05 9.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=129 | no trial arm names this drug |
| Anosmia (loss of smell) | 399 | 11.9 10.8–13.1ROR 12.0 · χ² 3,866 / p <1e-300 | 11.6 EB05 10.6 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=95 · 89% consumer | no trial arm names this drug |
| Sputum increased | 56 | 11.4 8.8–14.9ROR 11.5 · χ² 509 / p 5e-113 | 10.9 EB05 8.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=47 | no trial arm names this drug |
| Nasal oedema | 45 | 10.8 8.1–14.6ROR 10.8 · χ² 382 / p 3e-85 | 10.2 EB05 7.8 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | ♀ 100% (drug 68%) · 100% consumer | no trial arm names this drug |
| Hyperparathyroidism secondary | 63 | 10.7 8.4–13.8ROR 10.7 · χ² 533 / p 4e-118 | 10.2 EB05 8.2 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=62 | no trial arm names this drug |
| Nasal disorder | 66 | 10.7 8.4–13.6ROR 10.7 · χ² 555 / p 5e-123 | 10.2 EB05 8.2 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | 100% consumer | no trial arm names this drug |
| Essential hypertension | 62 | 10.3 8.0–13.3ROR 10.3 · χ² 500 / p 4e-111 | 9.8 EB05 7.8 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=60 | no trial arm names this drug |
| Paranasal sinus discomfort | 86 | 9.8 7.9–12.2ROR 9.8 · χ² 658 / p 2e-145 | 9.4 EB05 7.8 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=41 · 74% consumer | no trial arm names this drug |
| Infusion site discharge | 39 | 9.8 7.1–13.5ROR 9.8 · χ² 293 / p 5e-66 | 9.1 EB05 6.8 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious n=36 · ♀ 100% (drug 68%) · 100% consumer | no trial arm names this drug |
| Infusion site pruritus | 67 | 9.2 7.3–11.8ROR 9.3 · χ² 474 / p 3e-105 | 8.7 EB05 7.1 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=44 | no trial arm names this drug |
| Multiple allergies | 161 | 8.8 7.5–10.3ROR 8.8 · χ² 1,085 / p 3e-238 | 8.5 EB05 7.5 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=96 · 71% consumer | no trial arm names this drug |
| Middle ear effusion | 45 | 8.8 6.5–11.8ROR 8.8 · χ² 297 / p 8e-67 | 8.2 EB05 6.3 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=26 · ♀ 100% (drug 68%) · 100% consumer | no trial arm names this drug |
| Pre-existing condition improved | 128 | 8.7 7.3–10.4ROR 8.7 · χ² 848 / p 8e-187 | 8.4 EB05 7.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=42 | no trial arm names this drug |
| Upper-airway cough syndrome | 162 | 8.5 7.3–9.9ROR 8.5 · χ² 1,042 / p 8e-229 | 8.2 EB05 7.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=73 · 73% consumer | no trial arm names this drug |
| Biliary dyskinesia | 33 | 8.3 5.8–11.6ROR 8.3 · χ² 199 / p 2e-45 | 7.5 EB05 5.5 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=33 · ♀ 100% (drug 68%) | no trial arm names this drug |
| Sinus headache | 115 | 8.2 6.9–9.9ROR 8.3 · χ² 711 / p 5e-157 | 7.9 EB05 6.8 · IC025 +2.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=41 | no trial arm names this drug |
| Diastolic dysfunction | 59 | 8.2 6.3–10.6ROR 8.2 · χ² 356 / p 9e-80 | 7.7 EB05 6.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=59 · ♀ 100% (drug 68%) · 100% clinician | no trial arm names this drug |
| Sinus operation | 45 | 8.1 6.0–10.9ROR 8.1 · χ² 269 / p 1e-60 | 7.5 EB05 5.8 · IC025 +2.4 3/3 methods agree | Reporting / coding artifact | serious n=31 | no trial arm names this drug |
| Epistaxis (nosebleed) | 1,415 | 8.1 7.7–8.5ROR 8.3 · χ² 8,656 / p <1e-300 | 7.9 EB05 7.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 · 89% consumer | no trial arm names this drug |
| Nasal septum deviation | 36 | 7.9 5.7–11.0ROR 7.9 · χ² 206 / p 6e-47 | 7.2 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=30 · 100% consumer | no trial arm names this drug |
| Rebound acid hypersecretion | 56 | 7.8 6.0–10.2ROR 7.8 · χ² 321 / p 6e-72 | 7.3 EB05 5.8 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=56 | no trial arm names this drug |
| Infusion site bruising | 38 | 7.7 5.6–10.5ROR 7.7 · χ² 209 / p 1e-47 | 7.0 EB05 5.3 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=28 · ♀ 100% (drug 68%) | no trial arm names this drug |
| Sinus disorder | 343 | 7.4 6.7–8.2ROR 7.4 · χ² 1,862 / p <1e-300 | 7.2 EB05 6.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 10.0 | no trial arm names this drug |
| Infusion site haemorrhage | 56 | 7.4 5.7–9.6ROR 7.4 · χ² 298 / p 4e-67 | 6.9 EB05 5.5 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=43 | no trial arm names this drug |
| Pharyngolaryngeal pain | 91 | 7.2 5.9–8.9ROR 7.2 · χ² 474 / p 2e-105 | 6.9 EB05 5.8 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | 79% consumer | no trial arm names this drug |
| Candidiasis | 68 | 7.1 5.6–9.1ROR 7.2 · χ² 347 / p 8e-78 | 6.8 EB05 5.5 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=32 · 71% consumer | no trial arm names this drug |
| Seasonal allergy | 226 | 6.8 6.0–7.8ROR 6.9 · χ² 1,105 / p 2e-242 | 6.7 EB05 6.0 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=145 | no trial arm names this drug |
| Nasal polyps | 75 | 6.6 5.3–8.3ROR 6.7 · χ² 348 / p 5e-78 | 6.3 EB05 5.2 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=53 | no trial arm names this drug |
| Spinal osteoarthritis | 136 | 6.6 5.6–7.8ROR 6.6 · χ² 628 / p 6e-139 | 6.4 EB05 5.5 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 8.1 | no trial arm names this drug |
| Pulmonary function test decreased | 67 | 6.5 5.1–8.3ROR 6.5 · χ² 302 / p 6e-68 | 6.2 EB05 5.0 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious n=53 | no trial arm names this drug |
Trial evidence (ClinicalTrials.gov)
ClinicalTrials.gov returned results-bearing trials mentioning Acetaminophen only as a background or rescue medication (NCT03472469, NCT04452344); no trial listing it as the tested intervention was cached, so no trial cross-check is shown.
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 |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 4,335 | 1.4 1.4–1.4ROR 1.4 · χ² 503 / p 1e-111 | 1.4 EB05 1.4 · IC025 +0.4 | Reporting / coding artifact | serious PRR 1.0 · 82% consumer | no trial arm names this drug |
| Fatigue (tiredness) | 3,340 | 1.8 1.8–1.9ROR 1.9 · χ² 1,267 / p 1e-277 | 1.8 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.4 | no trial arm names this drug |
| Headache | 3,127 | 2.1 2.0–2.2ROR 2.2 · χ² 1,875 / p <1e-300 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 2.4 | no trial arm names this drug |
| Nausea | 2,948 | 1.6 1.5–1.6ROR 1.6 · χ² 645 / p 1e-142 | 1.6 EB05 1.5 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.0 | no trial arm names this drug |
| Dyspnoea (shortness of breath) | 2,939 | 2.2 2.1–2.3ROR 2.3 · χ² 1,959 / p <1e-300 | 2.2 EB05 2.1 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.5 | no trial arm names this drug |
| Diarrhoea (diarrhea) | 2,393 | 1.6 1.5–1.6ROR 1.6 · χ² 510 / p 4e-113 | 1.6 EB05 1.5 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.0 | no trial arm names this drug |
| Pain | 2,363 | 1.6 1.6–1.7ROR 1.7 · χ² 578 / p 6e-128 | 1.6 EB05 1.6 · IC025 +0.6 | Likely indication confounding term in indications; also in warnings | serious PRR 2.2 | no trial arm names this drug |
| Dizziness | 2,204 | 1.9 1.8–1.9ROR 1.9 · χ² 910 / p 4e-200 | 1.9 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.3 | no trial arm names this drug |
| Cough | 1,884 | 2.9 2.7–3.0ROR 2.9 · χ² 2,279 / p <1e-300 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial arm names this drug |
| Off label use (used outside approved label) | 1,806 | 0.9 0.8–0.9ROR 0.9 · χ² 32 / p 7e-9 | 0.9 EB05 0.8 · IC025 -0.3 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.8 | no trial arm names this drug |
| Pneumonia (lung infection) | 1,645 | 2.2 2.1–2.3ROR 2.2 · χ² 1,024 / p 6e-225 | 2.1 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial arm names this drug |
| Anxiety | 1,617 | 2.4 2.3–2.5ROR 2.4 · χ² 1,327 / p 7e-291 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.0 | no trial arm names this drug |
| Arthralgia (joint pain) | 1,557 | 1.6 1.5–1.7ROR 1.6 · χ² 343 / p 8e-77 | 1.6 EB05 1.5 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.2 | no trial arm names this drug |
| Vomiting | 1,494 | 1.3 1.3–1.4ROR 1.4 · χ² 134 / p 2e-31 | 1.3 EB05 1.3 · IC025 +0.3 | Not in label — unassessed | serious PRR 1.7 | no trial arm names this drug |
| Asthenia (weakness) | 1,455 | 1.6 1.6–1.7ROR 1.7 · χ² 362 / p 4e-81 | 1.6 EB05 1.6 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.0 | no trial arm names this drug |
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.
- Nasal discomfort — n=384, PRR 21.3
- Nasal ulcer — n=73, PRR 20.1
- Rhinitis allergic — n=153, PRR 15.0
- Acute sinusitis — n=59, PRR 14.9
- Chronic kidney disease-mineral and bone disorder — n=36, PRR 14.6
- Chronic sinusitis — n=115, PRR 13.3
- Rhinalgia — n=82, PRR 13.0
- Infective pulmonary exacerbation of cystic fibrosis — n=162, PRR 12.8
- Nasal dryness — n=176, PRR 12.2
- Nephrogenic anaemia — n=129, PRR 11.9
✓ A hand-written Bradford Hill causality assessment exists for this drug: Acetaminophen (paracetamol) ↔ Liver injury / hepatotoxicity.
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 Acetaminophen?
In FDA FAERS, the most frequently co-reported reaction terms for Acetaminophen are fatigue, headache, nausea, dyspnoea, diarrhoea, pain. 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 Acetaminophen have an FDA boxed warning?
No. The FDA label retrieved for Acetaminophen has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Acetaminophen 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 004c39cd-b4f4-1cae-e063-6394a90a0697, effective 20251003; matched on
openfda.generic_name.exact:"ACETAMINOPHEN") - 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, 1,175 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 - ClinicalTrials.gov API v2 (query
ACETAMINOPHEN, results-bearing studies sorted by enrollment)
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.