Drug · FAERS side-effect profile with label screen
Acetaminophen and Caffeine side effects: what 7,498 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Acetaminophen (Acetaminophen)
closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match
Who reports
7,498 reports · 31% serious · 114 with death outcome · 79% 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 2Reporting / coding artifact 12Not in label — unassessed 26
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. 358 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 |
|---|---|---|---|---|---|---|
| Drug effective for unapproved indication | 157 | 15.1 12.9–17.6ROR 15.4 · χ² 2,044 / p <1e-300 | 15.0 EB05 13.1 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=4 · 100% consumer | no trial data cached |
| Ulcer | 60 | 10.6 8.2–13.6ROR 10.6 · χ² 508 / p 7e-113 | 10.2 EB05 8.1 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.2 · 91% consumer | no trial data cached |
| Migraine | 284 | 8.4 7.5–9.4ROR 8.7 · χ² 1,844 / p <1e-300 | 8.3 EB05 7.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.9 · 84% consumer | no trial data cached |
| Therapeutic response unexpected | 117 | 7.3 6.1–8.7ROR 7.4 · χ² 627 / p 9e-139 | 7.1 EB05 6.1 · IC025 +2.5 3/3 methods agree | Reporting / coding artifact | serious PRR 16.8 · 97% consumer | no trial data cached |
| Gastric ulcer | 47 | 6.9 5.2–9.2ROR 7.0 · χ² 232 / p 1e-52 | 6.5 EB05 5.1 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 13.7 · 83% consumer | no trial data cached |
| Gastric disorder | 81 | 6.5 5.2–8.1ROR 6.6 · χ² 372 / p 3e-83 | 6.3 EB05 5.2 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 · 89% consumer | no trial data cached |
| Feeling jittery | 43 | 6.3 4.7–8.5ROR 6.3 · χ² 186 / p 9e-43 | 5.9 EB05 4.6 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=3 · 93% consumer | no trial data cached |
| Gastric haemorrhage | 25 | 6.0 4.1–8.9ROR 6.1 · χ² 100 / p 7e-24 | 5.5 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.7 · 96% consumer | no trial data cached |
| Incorrect drug administration duration | 50 | 4.9 3.7–6.5ROR 4.9 · χ² 152 / p 4e-35 | 4.7 EB05 3.7 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 19.1 · 100% consumer | no trial data cached |
| Drug ineffective for unapproved indication | 96 | 4.8 4.0–5.9ROR 4.9 · χ² 287 / p 1e-64 | 4.7 EB05 4.0 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious PRR 3.8 · 93% consumer | no trial data cached |
| End stage renal disease | 31 | 4.7 3.3–6.7ROR 4.7 · χ² 87 / p 6e-21 | 4.4 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Contraindicated product administered | 48 | 4.5 3.4–5.9ROR 4.5 · χ² 125 / p 2e-29 | 4.3 EB05 3.4 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 2.4 · 98% consumer | no trial data cached |
| Drug ineffective (drug did not work) | 2,054 | 4.4 4.2–4.5ROR 5.6 · χ² 5,676 / p <1e-300 | 4.4 EB05 4.2 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 1.7 · 96% consumer | no trial data cached |
| Drug effect incomplete | 56 | 4.3 3.3–5.5ROR 4.3 · χ² 136 / p 9e-32 | 4.1 EB05 3.3 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 2.8 · 88% consumer | no trial data cached |
| Drug administration error | 46 | 4.1 3.1–5.5ROR 4.2 · χ² 106 / p 3e-25 | 4.0 EB05 3.1 · IC025 +1.5 3/3 methods agree | Reporting / coding artifact | serious PRR 3.5 · 98% consumer | no trial data cached |
| Chronic kidney disease | 111 | 4.1 3.4–4.9ROR 4.1 · χ² 253 / p 3e-57 | 4.0 EB05 3.4 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.7 | no trial data cached |
| Vitamin d deficiency | 14 | 4.0 2.4–6.8ROR 4.0 · χ² 29 / p 4e-8 | 3.6 EB05 2.3 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 | no trial data cached |
| Drug effect less than expected | 20 | 4.0 2.6–6.2ROR 4.0 · χ² 41 / p 6e-11 | 3.7 EB05 2.5 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious n=3 · 90% consumer | no trial data cached |
| Product physical issue | 28 | 3.9 2.7–5.7ROR 3.9 · χ² 58 / p 1e-14 | 3.7 EB05 2.7 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious n=7 · 85% consumer | no trial data cached |
| Tooth fracture | 14 | 3.6 2.1–6.0ROR 3.6 · χ² 23 / p 7e-7 | 3.2 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.9 | no trial data cached |
| Dental caries | 14 | 3.5 2.1–6.0ROR 3.5 · χ² 23 / p 8e-7 | 3.2 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 | no trial data cached |
| Poor quality sleep | 27 | 3.5 2.4–5.1ROR 3.5 · χ² 46 / p 5e-12 | 3.4 EB05 2.4 · IC025 +1.1 3/3 methods agree | Reporting / coding artifact | serious PRR 1.4 · 100% consumer | no trial data cached |
| Product use in unapproved indication | 304 | 3.5 3.1–3.9ROR 3.6 · χ² 541 / p 6e-120 | 3.5 EB05 3.1 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 1.1 · 94% consumer | no trial data cached |
| Brain neoplasm | 11 | 3.3 1.9–6.0ROR 3.4 · χ² 16 / p 3e-5 | 3.0 EB05 1.8 · IC025 +0.6 | Not in label — unassessed | serious PRR 6.4 | no trial data cached |
| Impaired driving ability | 13 | 3.2 1.9–5.5ROR 3.2 · χ² 17 / p 1e-5 | 2.9 EB05 1.8 · IC025 +0.6 | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Seasonal allergy | 16 | 3.2 1.9–5.2ROR 3.2 · χ² 22 / p 2e-6 | 3.0 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious n=9 | no trial data cached |
| Abdominal discomfort | 189 | 3.2 2.7–3.6ROR 3.2 · χ² 279 / p 5e-63 | 3.1 EB05 2.8 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 · 91% consumer | no trial data cached |
| Product quality issue | 150 | 3.1 2.7–3.6ROR 3.2 · χ² 214 / p 9e-49 | 3.1 EB05 2.7 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 2.4 · 96% consumer | no trial data cached |
| Initial insomnia | 11 | 3.0 1.7–5.4ROR 3.0 · χ² 13 / p 2e-4 | 2.8 EB05 1.7 · IC025 +0.4 | Not in label — unassessed | serious n=3 | no trial data cached |
| Tubulointerstitial nephritis | 20 | 3.0 1.9–4.6ROR 3.0 · χ² 24 / p 4e-7 | 2.8 EB05 2.0 · IC025 +0.8 | Not in label — unassessed | serious PRR 5.6 | no trial data cached |
| Paraesthesia oral | 15 | 2.9 1.8–4.8ROR 2.9 · χ² 17 / p 2e-5 | 2.7 EB05 1.8 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.6 | no trial data cached |
| Back disorder | 17 | 2.9 1.8–4.7ROR 2.9 · χ² 19 / p 5e-6 | 2.7 EB05 1.8 · IC025 +0.6 | Likely indication confounding term in indications | serious PRR 6.5 | no trial data cached |
| Sinus disorder | 20 | 2.8 1.8–4.4ROR 2.8 · χ² 22 / p 2e-6 | 2.7 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious PRR 8.5 | no trial data cached |
| Bladder disorder | 10 | 2.8 1.5–5.2ROR 2.8 · χ² 10 / p 8e-4 | 2.6 EB05 1.5 · IC025 +0.3 | Not in label — unassessed | serious n=8 | no trial data cached |
| Euphoric mood | 10 | 2.7 1.5–5.0ROR 2.7 · χ² 9 / p 0.001 | 2.5 EB05 1.5 · IC025 +0.2 | Not in label — unassessed | – | no trial data cached |
| Micturition urgency | 11 | 2.7 1.5–4.9ROR 2.7 · χ² 10 / p 7e-4 | 2.5 EB05 1.5 · IC025 +0.3 | Not in label — unassessed | serious PRR 6.1 | no trial data cached |
| Abdominal pain upper | 194 | 2.6 2.3–3.0ROR 2.7 · χ² 198 / p 3e-45 | 2.6 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 · 84% consumer | no trial data cached |
| Hypoaesthesia oral | 14 | 2.6 1.5–4.4ROR 2.6 · χ² 12 / p 2e-4 | 2.5 EB05 1.6 · IC025 +0.4 | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Muscle tightness | 15 | 2.6 1.6–4.3ROR 2.6 · χ² 13 / p 1e-4 | 2.5 EB05 1.6 · IC025 +0.4 | Not in label — unassessed | serious PRR 6.2 | no trial data cached |
| Headache | 579 | 2.6 2.4–2.8ROR 2.7 · χ² 579 / p 4e-128 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Likely indication confounding term in indications | serious PRR 3.9 · 76% consumer | 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 |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 2,054 | 4.4 4.2–4.5ROR 5.6 · χ² 5,676 / p <1e-300 | 4.4 EB05 4.2 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 1.7 · 96% consumer | no trial data cached |
| Headache | 579 | 2.6 2.4–2.8ROR 2.7 · χ² 579 / p 4e-128 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Likely indication confounding term in indications | serious PRR 3.9 · 76% consumer | no trial data cached |
| Nausea | 422 | 1.5 1.4–1.6ROR 1.5 · χ² 71 / p 1e-17 | 1.5 EB05 1.4 · IC025 +0.4 | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Product use in unapproved indication | 304 | 3.5 3.1–3.9ROR 3.6 · χ² 541 / p 6e-120 | 3.5 EB05 3.1 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious PRR 1.1 · 94% consumer | no trial data cached |
| Migraine | 284 | 8.4 7.5–9.4ROR 8.7 · χ² 1,844 / p <1e-300 | 8.3 EB05 7.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.9 · 84% consumer | no trial data cached |
| Dizziness | 234 | 1.3 1.2–1.5ROR 1.3 · χ² 18 / p 1e-5 | 1.3 EB05 1.2 · IC025 +0.2 | Not in label — unassessed | serious PRR 2.1 · 77% consumer | no trial data cached |
| Insomnia (trouble sleeping) | 210 | 2.2 1.9–2.5ROR 2.2 · χ² 138 / p 3e-32 | 2.2 EB05 2.0 · IC025 +0.9 | Not in label — unassessed | serious PRR 2.6 · 85% consumer | no trial data cached |
| Abdominal pain upper | 194 | 2.6 2.3–3.0ROR 2.7 · χ² 198 / p 3e-45 | 2.6 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 · 84% consumer | no trial data cached |
| Abdominal discomfort | 189 | 3.2 2.7–3.6ROR 3.2 · χ² 279 / p 5e-63 | 3.1 EB05 2.8 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 · 91% consumer | no trial data cached |
| Anxiety | 163 | 1.6 1.4–1.9ROR 1.6 · χ² 36 / p 8e-10 | 1.6 EB05 1.4 · IC025 +0.4 | Not in label — unassessed | serious PRR 2.5 · 84% consumer | no trial data cached |
| Drug effective for unapproved indication | 157 | 15.1 12.9–17.6ROR 15.4 · χ² 2,044 / p <1e-300 | 15.0 EB05 13.1 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=4 · 100% consumer | no trial data cached |
| Feeling abnormal | 150 | 1.7 1.5–2.0ROR 1.8 · χ² 47 / p 3e-12 | 1.7 EB05 1.5 · IC025 +0.5 | Not in label — unassessed | serious PRR 3.6 · 87% consumer | no trial data cached |
| Product quality issue | 150 | 3.1 2.7–3.6ROR 3.2 · χ² 214 / p 9e-49 | 3.1 EB05 2.7 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 2.4 · 96% consumer | no trial data cached |
| Drug dependence | 142 | 2.4 2.1–2.9ROR 2.5 · χ² 120 / p 3e-28 | 2.4 EB05 2.1 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 4.7 · 99% consumer | no trial data cached |
| Incorrect dose administered | 128 | 1.6 1.3–1.9ROR 1.6 · χ² 28 / p 7e-8 | 1.6 EB05 1.4 · IC025 +0.4 | Reporting / coding artifact | serious PRR 2.9 · 91% consumer | 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.
- Drug effective for unapproved indication — n=157, PRR 15.1
- Ulcer — n=60, PRR 10.6
- Migraine — n=284, PRR 8.4
- Gastric ulcer — n=47, PRR 6.9
- Gastric disorder — n=81, PRR 6.5
- Feeling jittery — n=43, PRR 6.3
- Gastric haemorrhage — n=25, PRR 6.0
- End stage renal disease — n=31, PRR 4.7
- Chronic kidney disease — n=111, PRR 4.1
- Abdominal discomfort — n=189, PRR 3.2
✓ 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 and Caffeine?
In FDA FAERS, the most frequently co-reported reaction terms for Acetaminophen and Caffeine are headache, nausea, migraine, dizziness, insomnia, abdominal pain upper. 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 and Caffeine have an FDA boxed warning?
No. The FDA label retrieved for Acetaminophen and Caffeine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Acetaminophen and Caffeine 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, 398 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.