Drug · FAERS side-effect profile with label screen
Acetaminophen and Caffeine side effects: what 3,493 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
3,493 reports · 95% serious · 563 with death outcome · 65% 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
Reporting / coding artifact 2Lab value / disease marker 3Not in label — unassessed 35
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. 408 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 |
|---|---|---|---|---|---|---|
| Folliculitis | 169 | 99.8 86.1–115.8ROR 104.9 · χ² 16,173 / p <1e-300 | 97.1 EB05 85.5 · IC025 +6.0 3/3 methods agree | Not in label — unassessed | serious PRR 69.7 · ♀ 99% (drug 65%) · 96% clinician | no trial data cached |
| Helicobacter infection | 159 | 95.1 81.6–110.8ROR 99.6 · χ² 14,485 / p <1e-300 | 92.6 EB05 81.1 · IC025 +5.9 3/3 methods agree | Not in label — unassessed | serious PRR 59.8 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Pemphigus | 170 | 83.2 71.8–96.5ROR 87.4 · χ² 13,545 / p <1e-300 | 81.4 EB05 71.6 · IC025 +5.8 3/3 methods agree | Not in label — unassessed | serious PRR 49.7 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Hand deformity | 165 | 76.7 66.0–89.1ROR 80.4 · χ² 12,097 / p <1e-300 | 75.1 EB05 65.9 · IC025 +5.7 3/3 methods agree | Not in label — unassessed | serious PRR 49.7 · ♀ 100% (drug 65%) · 98% clinician | no trial data cached |
| Pericarditis | 173 | 63.0 54.4–72.9ROR 66.2 · χ² 10,386 / p <1e-300 | 61.9 EB05 54.5 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious PRR 37.9 · ♀ 95% (drug 65%) · 96% clinician | no trial data cached |
| Hypercholesterolaemia | 88 | 55.7 45.3–68.5ROR 57.1 · χ² 4,633 / p <1e-300 | 54.6 EB05 45.7 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious PRR 35.4 · ♀ 100% (drug 65%) · 98% clinician | no trial data cached |
| Synovitis | 164 | 55.0 47.4–64.0ROR 57.7 · χ² 8,576 / p <1e-300 | 54.2 EB05 47.6 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious PRR 34.5 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Bursitis | 95 | 47.6 39.0–58.1ROR 48.9 · χ² 4,259 / p <1e-300 | 46.8 EB05 39.5 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 33.3 · ♀ 98% (drug 65%) | no trial data cached |
| Joint range of motion decreased | 101 | 45.7 37.7–55.4ROR 47.0 · χ² 4,340 / p <1e-300 | 45.0 EB05 38.1 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 34.9 · ♀ 100% (drug 65%) · 91% clinician | no trial data cached |
| Glossodynia (burning tongue/mouth pain) | 165 | 44.6 38.4–51.8ROR 46.8 · χ² 6,949 / p <1e-300 | 44.1 EB05 38.7 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious PRR 38.5 · ♀ 100% (drug 65%) · 96% clinician | no trial data cached |
| Irritable bowel syndrome | 150 | 42.4 36.3–49.7ROR 44.3 · χ² 5,991 / p <1e-300 | 41.9 EB05 36.6 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 32.3 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Wound infection | 72 | 40.0 31.8–50.3ROR 40.8 · χ² 2,684 / p <1e-300 | 39.4 EB05 32.3 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 25.8 · ♀ 94% (drug 65%) · 96% clinician | no trial data cached |
| Wound | 169 | 36.7 31.7–42.5ROR 38.5 · χ² 5,806 / p <1e-300 | 36.4 EB05 32.0 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious PRR 26.3 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Autoimmune disorder | 56 | 35.3 27.2–45.8ROR 35.9 · χ² 1,823 / p <1e-300 | 34.7 EB05 27.8 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 22.7 · ♀ 100% (drug 65%) · 98% clinician | no trial data cached |
| Systemic lupus erythematosus | 202 | 34.5 30.1–39.4ROR 36.5 · χ² 6,505 / p <1e-300 | 34.2 EB05 30.4 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious PRR 21.2 · ♀ 92% (drug 65%) · 96% clinician | no trial data cached |
| Impaired healing | 177 | 32.5 28.2–37.6ROR 34.2 · χ² 5,356 / p <1e-300 | 32.3 EB05 28.5 · IC025 +4.6 3/3 methods agree | Reporting / coding artifact | serious PRR 23.6 · ♀ 99% (drug 65%) · 95% clinician | no trial data cached |
| Liver injury | 116 | 28.9 24.2–34.6ROR 29.9 · χ² 3,089 / p <1e-300 | 28.7 EB05 24.6 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 18.0 · ♀ 98% (drug 65%) · 94% clinician | no trial data cached |
| Red blood cell sedimentation rate increased | 53 | 28.8 22.0–37.7ROR 29.2 · χ² 1,390 / p <1e-300 | 28.4 EB05 22.6 · IC025 +4.1 3/3 methods agree | Lab value / disease marker | serious PRR 19.7 · ♀ 92% (drug 65%) | no trial data cached |
| Obesity | 75 | 28.3 22.6–35.5ROR 28.9 · χ² 1,943 / p <1e-300 | 28.0 EB05 23.1 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious PRR 19.8 · ♀ 96% (drug 65%) · 92% clinician | no trial data cached |
| Fibromyalgia | 113 | 28.1 23.4–33.7ROR 29.0 · χ² 2,911 / p <1e-300 | 27.8 EB05 23.8 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 22.2 · ♀ 100% (drug 65%) · 97% clinician | no trial data cached |
| Lower respiratory tract infection | 203 | 27.0 23.6–30.9ROR 28.6 · χ² 5,046 / p <1e-300 | 26.8 EB05 23.9 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 17.1 · ♀ 93% (drug 65%) | no trial data cached |
| Sciatica | 68 | 25.8 20.4–32.7ROR 26.3 · χ² 1,593 / p <1e-300 | 25.6 EB05 20.9 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 20.6 · ♀ 100% (drug 65%) · 93% clinician | no trial data cached |
| Type 2 diabetes mellitus | 141 | 25.2 21.4–29.6ROR 26.2 · χ² 3,239 / p <1e-300 | 25.0 EB05 21.7 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 16.0 · ♀ 98% (drug 65%) · 97% clinician | no trial data cached |
| Affect lability | 34 | 21.2 15.1–29.6ROR 21.4 · χ² 632 / p 1e-139 | 20.9 EB05 15.6 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 17.8 · ♀ 100% (drug 65%) · 100% clinician | no trial data cached |
| Prescribed overdose | 68 | 21.2 16.7–26.8ROR 21.6 · χ² 1,283 / p 3e-281 | 21.0 EB05 17.1 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 21.7 · ♀ 100% (drug 65%) · 94% clinician | no trial data cached |
| Lower limb fracture | 67 | 21.1 16.7–26.8ROR 21.5 · χ² 1,262 / p 1e-276 | 21.0 EB05 17.1 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 · ♀ 95% (drug 65%) · 91% clinician | no trial data cached |
| Psoriatic arthropathy | 139 | 20.8 17.7–24.5ROR 21.6 · χ² 2,598 / p <1e-300 | 20.7 EB05 18.0 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 15.8 · ♀ 100% (drug 65%) · 96% clinician | no trial data cached |
| Liver function test increased | 73 | 20.6 16.4–25.9ROR 21.0 · χ² 1,340 / p 1e-293 | 20.5 EB05 16.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 19.4 · ♀ 94% (drug 65%) | no trial data cached |
| Blood calcium decreased | 37 | 19.7 14.3–27.2ROR 19.9 · χ² 638 / p 4e-141 | 19.5 EB05 14.7 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 14.9 · ♀ 88% (drug 65%) | no trial data cached |
| Contraindicated product administered | 97 | 19.4 15.9–23.6ROR 19.9 · χ² 1,668 / p <1e-300 | 19.2 EB05 16.2 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious PRR 14.5 · ♀ 100% (drug 65%) · 98% clinician | no trial data cached |
| Pulmonary fibrosis | 57 | 18.0 13.9–23.2ROR 18.2 · χ² 894 / p 1e-196 | 17.8 EB05 14.2 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 10.9 · ♀ 100% (drug 65%) | no trial data cached |
| Delirium | 103 | 17.9 14.8–21.7ROR 18.4 · χ² 1,628 / p <1e-300 | 17.8 EB05 15.1 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 11.0 · ♀ 94% (drug 65%) · 90% clinician | no trial data cached |
| Coeliac disease | 29 | 17.8 12.4–25.6ROR 17.9 · χ² 442 / p 2e-98 | 17.5 EB05 12.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 13.3 · ♀ 96% (drug 65%) · 93% clinician | no trial data cached |
| Infusion related reaction (reaction during infusion) | 193 | 17.6 15.3–20.2ROR 18.6 · χ² 3,004 / p <1e-300 | 17.5 EB05 15.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 13.4 · ♀ 97% (drug 65%) · 95% clinician | no trial data cached |
| C-reactive protein increased | 106 | 17.5 14.5–21.2ROR 18.1 · χ² 1,635 / p <1e-300 | 17.4 EB05 14.8 · IC025 +3.7 3/3 methods agree | Lab value / disease marker | serious PRR 11.0 | no trial data cached |
| Night sweats | 93 | 17.4 14.2–21.3ROR 17.8 · χ² 1,418 / p <1e-300 | 17.3 EB05 14.5 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 18.0 · ♀ 100% (drug 65%) · 91% clinician | no trial data cached |
| Laryngitis | 31 | 17.2 12.1–24.4ROR 17.3 · χ² 455 / p 2e-101 | 16.9 EB05 12.4 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=31 · ♀ 100% (drug 65%) · 94% clinician | no trial data cached |
| Joint dislocation | 30 | 17.1 12.0–24.5ROR 17.3 · χ² 439 / p 8e-98 | 16.9 EB05 12.2 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 11.6 · ♀ 93% (drug 65%) | no trial data cached |
| Gait inability | 94 | 17.1 14.0–20.9ROR 17.5 · χ² 1,406 / p <1e-300 | 17.0 EB05 14.3 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious PRR 12.8 · ♀ 93% (drug 65%) | no trial data cached |
| Arthropathy | 155 | 16.7 14.3–19.5ROR 17.5 · χ² 2,275 / p <1e-300 | 16.6 EB05 14.6 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 12.3 · ♀ 95% (drug 65%) · 94% clinician | 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 |
|---|---|---|---|---|---|---|
| Pain | 392 | 3.8 3.5–4.2ROR 4.2 · χ² 840 / p 6e-185 | 3.8 EB05 3.5 · IC025 +1.8 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 3.5 | no trial data cached |
| Fatigue (tiredness) | 390 | 3.0 2.7–3.3ROR 3.3 · χ² 543 / p 2e-120 | 3.0 EB05 2.8 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
| Pyrexia (fever) | 367 | 6.4 5.8–7.0ROR 7.0 · χ² 1,682 / p <1e-300 | 6.3 EB05 5.8 · IC025 +2.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.7 | no trial data cached |
| Headache | 352 | 3.4 3.1–3.7ROR 3.6 · χ² 604 / p 1e-133 | 3.4 EB05 3.1 · IC025 +1.6 3/3 methods agree | Likely indication confounding term in indications | serious PRR 4.0 | no trial data cached |
| Dyspnoea (shortness of breath) | 343 | 3.6 3.3–4.0ROR 3.9 · χ² 673 / p 1e-148 | 3.6 EB05 3.3 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.0 | no trial data cached |
| Confusional state (confusion) | 289 | 10.7 9.6–12.0ROR 11.6 · χ² 2,556 / p <1e-300 | 10.7 EB05 9.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 8.2 | no trial data cached |
| Rash | 276 | 3.8 3.4–4.3ROR 4.1 · χ² 584 / p 2e-129 | 3.8 EB05 3.4 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.0 · ♀ 86% (drug 65%) | no trial data cached |
| Vomiting | 274 | 3.5 3.1–3.9ROR 3.7 · χ² 500 / p 4e-111 | 3.5 EB05 3.2 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.1 | no trial data cached |
| Arthralgia (joint pain) | 263 | 3.8 3.4–4.3ROR 4.0 · χ² 553 / p 1e-122 | 3.8 EB05 3.4 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 · ♀ 87% (drug 65%) | no trial data cached |
| Hypertension (high blood pressure) | 247 | 7.0 6.2–7.9ROR 7.5 · χ² 1,276 / p 1e-279 | 6.9 EB05 6.2 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 · ♀ 91% (drug 65%) | no trial data cached |
| Malaise (feeling unwell) | 246 | 3.4 3.0–3.8ROR 3.5 · χ² 414 / p 2e-92 | 3.3 EB05 3.0 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 | no trial data cached |
| Fall | 222 | 4.0 3.5–4.6ROR 4.2 · χ² 506 / p 2e-112 | 4.0 EB05 3.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
| General physical health deterioration | 218 | 11.4 10.0–13.0ROR 12.1 · χ² 2,068 / p <1e-300 | 11.3 EB05 10.1 · IC025 +3.3 3/3 methods agree | Reporting / coding artifact | serious PRR 8.0 · ♀ 89% (drug 65%) · 91% clinician | no trial data cached |
| Pain in extremity | 217 | 4.4 3.9–5.0ROR 4.6 · χ² 578 / p 6e-128 | 4.4 EB05 3.9 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | no trial data cached |
| Condition aggravated | 213 | 4.2 3.7–4.8ROR 4.4 · χ² 531 / p 1e-117 | 4.2 EB05 3.7 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 3.9 | 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.
- Folliculitis — n=169, PRR 99.8
- Helicobacter infection — n=159, PRR 95.1
- Pemphigus — n=170, PRR 83.2
- Hand deformity — n=165, PRR 76.7
- Pericarditis — n=173, PRR 63.0
- Hypercholesterolaemia — n=88, PRR 55.7
- Synovitis — n=164, PRR 55.0
- Bursitis — n=95, PRR 47.6
- Joint range of motion decreased — n=101, PRR 45.7
- Glossodynia — n=165, PRR 44.6
✓ 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 pain, fatigue, pyrexia, headache, dyspnoea, confusional state. 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, 448 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.