Drug · FAERS side-effect profile with label screen

Acetaminophen side effects: what 935 FDA adverse event reports show

Acetaminophen, Dextromethorphan Hydrobromide, Guaifenesin, And Phenylephrine Hydrochloride · 21 reaction terms · 468 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Who reports

935 reports · 41% serious · 20 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 14 strongest signals

Reporting / coding artifact 4Lab value / disease marker 1Not in label — unassessed 9

What the badges mean

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. 7 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
Disease recurrence	107	50.4 42.2–60.3ROR 56.8 · χ² 5,132 / p <1e-300	49.9 EB05 42.4 · IC025 +5.0 3/3 methods agree	Reporting / coding artifact	serious PRR 4.0 · 86% consumer	no trial data cached
Covid-19	131	16.6 14.2–19.5ROR 19.2 · χ² 1,922 / p <1e-300	16.6 EB05 14.3 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 3.2 · 82% consumer	no trial data cached
Brain fog	8	12.3 6.2–24.5ROR 12.4 · χ² 72 / p 1e-17	9.7 EB05 4.5 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 29.4	no trial data cached
Sars-cov-2 test positive	7	11.8 5.6–24.6ROR 11.8 · χ² 59 / p 1e-14	8.7 EB05 3.9 · IC025 +1.5 3/3 methods agree	Lab value / disease marker	serious n=2	no trial data cached
Nasal congestion (stuffy nose)	28	10.7 7.5–15.5ROR 11.0 · χ² 238 / p 5e-54	10.1 EB05 7.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 15.1 · ♀ 93% (drug 68%)	no trial data cached
Respiratory tract congestion	7	9.9 4.7–20.7ROR 9.9 · χ² 47 / p 3e-12	7.1 EB05 3.4 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 9.2	no trial data cached
Nasopharyngitis (common cold)	78	9.5 7.7–11.7ROR 10.2 · χ² 588 / p 4e-130	9.2 EB05 7.6 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 11.1	no trial data cached
Anosmia (loss of smell)	6	9.3 4.2–20.6ROR 9.3 · χ² 36 / p 8e-10	6.3 EB05 2.9 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious n=1	no trial data cached
Choking	8	9.2 4.6–18.4ROR 9.3 · χ² 51 / p 5e-13	6.8 EB05 3.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 15.4	no trial data cached
Product administration error	8	9.0 4.5–17.9ROR 9.1 · χ² 49 / p 1e-12	6.6 EB05 3.4 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9	no trial data cached
Dysgeusia (altered taste)	29	8.7 6.1–12.5ROR 9.0 · χ² 191 / p 1e-43	8.0 EB05 5.7 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 2.4 · 89% consumer	no trial data cached
Aphonia	5	8.0 3.4–19.3ROR 8.1 · χ² 24 / p 4e-7	5.2 EB05 2.3 · IC025 +0.7 3/3 methods agree	Not in label — unassessed	serious PRR 8.5	no trial data cached
Drug administration error	9	6.5 3.4–12.4ROR 6.5 · χ² 37 / p 8e-10	5.0 EB05 2.8 · IC025 +1.2 3/3 methods agree	Reporting / coding artifact	serious PRR 6.0	no trial data cached
Expired product administered	7	4.7 2.3–9.9ROR 4.8 · χ² 17 / p 2e-5	3.7 EB05 2.0 · IC025 +0.6	Reporting / coding artifact	serious n=4	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
Covid-19	131	16.6 14.2–19.5ROR 19.2 · χ² 1,922 / p <1e-300	16.6 EB05 14.3 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 3.2 · 82% consumer	no trial data cached
Disease recurrence	107	50.4 42.2–60.3ROR 56.8 · χ² 5,132 / p <1e-300	49.9 EB05 42.4 · IC025 +5.0 3/3 methods agree	Reporting / coding artifact	serious PRR 4.0 · 86% consumer	no trial data cached
Nasopharyngitis (common cold)	78	9.5 7.7–11.7ROR 10.2 · χ² 588 / p 4e-130	9.2 EB05 7.6 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 11.1	no trial data cached
Dysgeusia (altered taste)	29	8.7 6.1–12.5ROR 9.0 · χ² 191 / p 1e-43	8.0 EB05 5.7 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 2.4 · 89% consumer	no trial data cached
Nasal congestion (stuffy nose)	28	10.7 7.5–15.5ROR 11.0 · χ² 238 / p 5e-54	10.1 EB05 7.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 15.1 · ♀ 93% (drug 68%)	no trial data cached
Drug administration error	9	6.5 3.4–12.4ROR 6.5 · χ² 37 / p 8e-10	5.0 EB05 2.8 · IC025 +1.2 3/3 methods agree	Reporting / coding artifact	serious PRR 6.0	no trial data cached
Completed suicide (death by suicide)	8	2.1 1.1–4.3ROR 2.1 · χ² 4 / p 0.026	2.0 EB05 1.1 · IC025 -0.2 PRR-only: not supported by EBGM or IC	Outcome field, not a reaction	serious PRR 3.0	no trial data cached
Product administration error	8	9.0 4.5–17.9ROR 9.1 · χ² 49 / p 1e-12	6.6 EB05 3.4 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9	no trial data cached
Choking	8	9.2 4.6–18.4ROR 9.3 · χ² 51 / p 5e-13	6.8 EB05 3.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 15.4	no trial data cached
Brain fog	8	12.3 6.2–24.5ROR 12.4 · χ² 72 / p 1e-17	9.7 EB05 4.5 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 29.4	no trial data cached
Expired product administered	7	4.7 2.3–9.9ROR 4.8 · χ² 17 / p 2e-5	3.7 EB05 2.0 · IC025 +0.6	Reporting / coding artifact	serious n=4	no trial data cached
Respiratory tract congestion	7	9.9 4.7–20.7ROR 9.9 · χ² 47 / p 3e-12	7.1 EB05 3.4 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 9.2	no trial data cached
Sars-cov-2 test positive	7	11.8 5.6–24.6ROR 11.8 · χ² 59 / p 1e-14	8.7 EB05 3.9 · IC025 +1.5 3/3 methods agree	Lab value / disease marker	serious n=2	no trial data cached
Anosmia (loss of smell)	6	9.3 4.2–20.6ROR 9.3 · χ² 36 / p 8e-10	6.3 EB05 2.9 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious n=1	no trial data cached
Aphonia	5	8.0 3.4–19.3ROR 8.1 · χ² 24 / p 4e-7	5.2 EB05 2.3 · IC025 +0.7 3/3 methods agree	Not in label — unassessed	serious PRR 8.5	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.

Covid-19 — n=131, PRR 16.6
Nasal congestion — n=28, PRR 10.7
Nasopharyngitis — n=78, PRR 9.5
Dysgeusia — n=29, PRR 8.7

✓ 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 covid-19, nasopharyngitis, dysgeusia, nasal congestion, choking, brain fog. 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, field patient.drug.openfda.generic_name.exact, 21 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.