Drug · FAERS side-effect profile with label screen
Acetaminophen and Caffeine side effects: what 822 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
822 reports · 88% serious · 74 with death outcome · 84% 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
Labeled adverse reaction 1Likely indication confounding 1Reporting / coding artifact 4Lab value / disease marker 1Not in label — unassessed 33
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.
- 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.
- 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. 91 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 |
|---|---|---|---|---|---|---|
| Blood calcium decreased | 216 | 498.0 443.4–559.2ROR 675.1 · χ² 104,620 / p <1e-300 | 468.0 EB05 417.9 · IC025 +7.6 3/3 methods agree | Lab value / disease marker | serious PRR 397.7 | no trial data cached |
| Orthostatic hypotension (dizziness on standing) | 216 | 319.7 284.9–358.9ROR 433.3 · χ² 67,511 / p <1e-300 | 307.1 EB05 274.3 · IC025 +7.3 3/3 methods agree | Not in label — unassessed | serious PRR 232.8 | no trial data cached |
| Sedation | 212 | 209.1 186.1–235.0ROR 281.5 · χ² 43,402 / p <1e-300 | 203.6 EB05 181.7 · IC025 +6.9 3/3 methods agree | Not in label — unassessed | serious PRR 186.2 | no trial data cached |
| Hand deformity | 101 | 198.4 165.2–238.4ROR 226.1 · χ² 19,503 / p <1e-300 | 189.9 EB05 160.8 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious PRR 139.4 | no trial data cached |
| Folliculitis | 72 | 179.0 143.5–223.4ROR 196.1 · χ² 12,487 / p <1e-300 | 169.8 EB05 139.4 · IC025 +5.9 3/3 methods agree | Not in label — unassessed | serious PRR 136.0 | no trial data cached |
| Helicobacter infection | 69 | 173.8 138.6–218.0ROR 189.6 · χ² 11,609 / p <1e-300 | 164.8 EB05 134.7 · IC025 +5.9 3/3 methods agree | Not in label — unassessed | serious PRR 118.8 | no trial data cached |
| Depressed level of consciousness | 215 | 139.7 124.5–156.8ROR 188.8 · χ² 29,360 / p <1e-300 | 137.3 EB05 122.5 · IC025 +6.5 3/3 methods agree | Not in label — unassessed | serious PRR 92.9 | no trial data cached |
| Pemphigus | 67 | 138.2 109.8–174.0ROR 150.4 · χ² 8,946 / p <1e-300 | 132.3 EB05 107.8 · IC025 +5.7 3/3 methods agree | Not in label — unassessed | serious PRR 89.7 · 93% clinician | no trial data cached |
| Cognitive disorder | 219 | 120.7 107.7–135.2ROR 164.1 · χ² 25,802 / p <1e-300 | 118.9 EB05 106.2 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious PRR 109.6 | no trial data cached |
| Drug level increased | 67 | 103.6 82.3–130.4ROR 112.7 · χ² 6,683 / p <1e-300 | 100.3 EB05 81.7 · IC025 +5.5 3/3 methods agree | Reporting / coding artifact | serious PRR 74.4 | no trial data cached |
| Pericarditis | 65 | 99.9 79.1–126.2ROR 108.4 · χ² 6,244 / p <1e-300 | 96.7 EB05 78.6 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious PRR 65.3 · 91% clinician | no trial data cached |
| Mobility decreased | 275 | 98.3 89.3–108.3ROR 147.3 · χ² 26,383 / p <1e-300 | 97.3 EB05 88.0 · IC025 +6.2 3/3 methods agree | Not in label — unassessed | serious PRR 94.1 | no trial data cached |
| Synovitis | 67 | 95.0 75.5–119.6ROR 103.4 · χ² 6,123 / p <1e-300 | 92.3 EB05 75.2 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious PRR 64.6 · 93% clinician | no trial data cached |
| Sciatica | 54 | 87.1 67.3–112.8ROR 93.2 · χ² 4,500 / p <1e-300 | 84.3 EB05 67.1 · IC025 +5.2 3/3 methods agree | Not in label — unassessed | serious PRR 76.0 | no trial data cached |
| Glossodynia (burning tongue/mouth pain) | 70 | 80.1 64.0–100.3ROR 87.5 · χ² 5,379 / p <1e-300 | 78.2 EB05 64.0 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious PRR 75.3 | no trial data cached |
| Contraindicated product administered | 93 | 78.9 65.1–95.6ROR 88.8 · χ² 7,062 / p <1e-300 | 77.4 EB05 65.1 · IC025 +5.5 3/3 methods agree | Reporting / coding artifact | serious PRR 63.8 | no trial data cached |
| Irritable bowel syndrome | 61 | 73.0 57.3–93.0ROR 78.8 · χ² 4,254 / p <1e-300 | 71.3 EB05 57.5 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious PRR 60.2 · 93% clinician | no trial data cached |
| Joint range of motion decreased | 37 | 70.8 51.7–97.0ROR 74.1 · χ² 2,471 / p <1e-300 | 68.2 EB05 51.7 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 58.6 | no trial data cached |
| Wound infection | 28 | 65.9 45.8–94.9ROR 68.2 · χ² 1,721 / p <1e-300 | 63.0 EB05 45.8 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 45.9 | no trial data cached |
| Balance disorder | 218 | 64.4 57.5–72.2ROR 87.3 · χ² 13,563 / p <1e-300 | 63.9 EB05 57.1 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious PRR 66.7 | no trial data cached |
| Systemic lupus erythematosus | 81 | 58.5 47.6–72.0ROR 64.8 · χ² 4,521 / p <1e-300 | 57.7 EB05 47.9 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious PRR 39.0 · 94% clinician | no trial data cached |
| Autoimmune disorder | 21 | 56.1 36.7–85.6ROR 57.5 · χ² 1,080 / p 4e-237 | 53.4 EB05 36.8 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 39.0 | no trial data cached |
| Muscle spasticity | 27 | 55.7 38.4–80.7ROR 57.5 · χ² 1,393 / p <1e-300 | 53.5 EB05 38.6 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious PRR 51.7 | no trial data cached |
| Bursitis | 26 | 55.1 37.7–80.4ROR 56.8 · χ² 1,325 / p 2e-290 | 53.0 EB05 38.0 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 42.1 | no trial data cached |
| Impaired healing | 69 | 53.7 42.8–67.3ROR 58.5 · χ² 3,515 / p <1e-300 | 52.9 EB05 43.2 · IC025 +4.9 3/3 methods agree | Reporting / coding artifact | serious PRR 42.2 | no trial data cached |
| Electrocardiogram qt prolonged | 67 | 47.6 37.8–59.9ROR 51.7 · χ² 3,008 / p <1e-300 | 46.9 EB05 38.2 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious PRR 31.4 | no trial data cached |
| Wound | 51 | 46.9 35.9–61.2ROR 49.9 · χ² 2,243 / p <1e-300 | 46.0 EB05 36.4 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 36.3 | no trial data cached |
| Lower respiratory tract infection | 81 | 45.7 37.1–56.2ROR 50.6 · χ² 3,496 / p <1e-300 | 45.1 EB05 37.5 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious PRR 31.4 · 94% clinician | no trial data cached |
| Prescribed overdose | 32 | 42.2 30.1–59.4ROR 43.9 · χ² 1,247 / p 2e-273 | 41.2 EB05 30.6 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 46.8 | no trial data cached |
| Deformity | 15 | 40.9 24.8–67.5ROR 41.6 · χ² 544 / p 1e-120 | 39.0 EB05 25.1 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 30.4 | no trial data cached |
| Fibromyalgia | 38 | 40.0 29.3–54.5ROR 41.9 · χ² 1,405 / p <1e-300 | 39.2 EB05 29.8 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious PRR 34.2 | no trial data cached |
| Therapeutic product effect decreased | 68 | 39.1 31.2–49.2ROR 42.6 · χ² 2,491 / p <1e-300 | 38.7 EB05 31.6 · IC025 +4.5 3/3 methods agree | Reporting / coding artifact | serious PRR 50.2 · 91% clinician | no trial data cached |
| Hypercholesterolaemia | 13 | 34.7 20.2–59.5ROR 35.2 · χ² 392 / p 1e-87 | 33.1 EB05 20.6 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 24.0 | no trial data cached |
| Arthropathy | 74 | 33.9 27.3–42.1ROR 37.1 · χ² 2,332 / p <1e-300 | 33.6 EB05 27.6 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 26.9 | no trial data cached |
| Liver injury | 32 | 33.8 24.1–47.5ROR 35.1 · χ² 986 / p 1e-216 | 33.2 EB05 24.6 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 22.8 | no trial data cached |
| Obesity | 21 | 33.6 22.0–51.3ROR 34.5 · χ² 632 / p 9e-140 | 32.7 EB05 22.5 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 25.4 | no trial data cached |
| Bladder disorder | 13 | 33.4 19.5–57.2ROR 33.9 · χ² 376 / p 4e-84 | 31.9 EB05 19.8 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Blister | 73 | 33.3 26.7–41.4ROR 36.4 · χ² 2,256 / p <1e-300 | 33.0 EB05 27.1 · IC025 +4.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 35.8 | no trial data cached |
| Ear pain | 25 | 32.8 22.3–48.3ROR 33.8 · χ² 740 / p 3e-163 | 32.1 EB05 22.8 · IC025 +3.7 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 34.4 · 92% clinician | no trial data cached |
| Night sweats | 41 | 32.5 24.1–43.8ROR 34.2 · χ² 1,222 / p 6e-268 | 32.0 EB05 24.6 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 36.3 | 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 | 343 | 14.2 13.1–15.4ROR 23.7 · χ² 4,330 / p <1e-300 | 14.2 EB05 13.0 · IC025 +3.6 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 14.4 | no trial data cached |
| Mobility decreased | 275 | 98.3 89.3–108.3ROR 147.3 · χ² 26,383 / p <1e-300 | 97.3 EB05 88.0 · IC025 +6.2 3/3 methods agree | Not in label — unassessed | serious PRR 94.1 | no trial data cached |
| Fall | 235 | 18.0 16.2–20.1ROR 24.9 · χ² 3,824 / p <1e-300 | 18.0 EB05 16.2 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 | no trial data cached |
| Constipation | 223 | 26.3 23.5–29.4ROR 35.7 · χ² 5,456 / p <1e-300 | 26.2 EB05 23.5 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious PRR 30.6 | no trial data cached |
| Hypotension (low blood pressure) | 220 | 28.1 25.0–31.4ROR 37.9 · χ² 5,761 / p <1e-300 | 28.0 EB05 25.0 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 21.2 | no trial data cached |
| Cognitive disorder | 219 | 120.7 107.7–135.2ROR 164.1 · χ² 25,802 / p <1e-300 | 118.9 EB05 106.2 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious PRR 109.6 | no trial data cached |
| Balance disorder | 218 | 64.4 57.5–72.2ROR 87.3 · χ² 13,563 / p <1e-300 | 63.9 EB05 57.1 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious PRR 66.7 | no trial data cached |
| Orthostatic hypotension (dizziness on standing) | 216 | 319.7 284.9–358.9ROR 433.3 · χ² 67,511 / p <1e-300 | 307.1 EB05 274.3 · IC025 +7.3 3/3 methods agree | Not in label — unassessed | serious PRR 232.8 | no trial data cached |
| Blood calcium decreased | 216 | 498.0 443.4–559.2ROR 675.1 · χ² 104,620 / p <1e-300 | 468.0 EB05 417.9 · IC025 +7.6 3/3 methods agree | Lab value / disease marker | serious PRR 397.7 | no trial data cached |
| Depressed level of consciousness | 215 | 139.7 124.5–156.8ROR 188.8 · χ² 29,360 / p <1e-300 | 137.3 EB05 122.5 · IC025 +6.5 3/3 methods agree | Not in label — unassessed | serious PRR 92.9 | no trial data cached |
| Sedation | 212 | 209.1 186.1–235.0ROR 281.5 · χ² 43,402 / p <1e-300 | 203.6 EB05 181.7 · IC025 +6.9 3/3 methods agree | Not in label — unassessed | serious PRR 186.2 | no trial data cached |
| Toxicity to various agents | 200 | 30.4 27.0–34.3ROR 39.9 · χ² 5,703 / p <1e-300 | 30.3 EB05 27.0 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 20.4 | no trial data cached |
| Drug interaction | 132 | 21.2 18.2–24.8ROR 25.1 · χ² 2,543 / p <1e-300 | 21.2 EB05 18.3 · IC025 +4.0 3/3 methods agree | Reporting / coding artifact | serious PRR 15.4 | no trial data cached |
| Hand deformity | 101 | 198.4 165.2–238.4ROR 226.1 · χ² 19,503 / p <1e-300 | 189.9 EB05 160.8 · IC025 +6.3 3/3 methods agree | Not in label — unassessed | serious PRR 139.4 | no trial data cached |
| Abdominal discomfort | 98 | 15.0 12.4–18.0ROR 16.9 · χ² 1,273 / p 5e-279 | 14.9 EB05 12.5 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 21.2 | 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.
- Orthostatic hypotension — n=216, PRR 319.7
- Sedation — n=212, PRR 209.1
- Hand deformity — n=101, PRR 198.4
- Folliculitis — n=72, PRR 179.0
- Helicobacter infection — n=69, PRR 173.8
- Depressed level of consciousness — n=215, PRR 139.7
- Pemphigus — n=67, PRR 138.2
- Cognitive disorder — n=219, PRR 120.7
- Pericarditis — n=65, PRR 99.9
- Mobility decreased — n=275, PRR 98.3
✓ 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, mobility decreased, fall, constipation, hypotension, cognitive disorder. 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, 131 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.