Aspirin 81 side effects: what 508,598 FDA adverse event reports show
Drug class
Nonsteroidal Anti-inflammatory Drug, Platelet Aggregation Inhibitor
Label matched
Aspirin 81 Mg (Aspirin Enteric Coated)
Who reports
508,598 reports · 72% serious · 46,531 with death outcome · 49% female
Used for
(s) for the temporary relief of minor aches and pain or as recommended by your doctor. Because of its delayed action, this product will not provide fast relief of headaches or other symptoms needing immediate relief.
What it is
Acetylsalicylic acid is a member of the class of benzoic acids that is salicylic acid in which the hydrogen that is attached to the phenolic hydroxy group has been replaced by an acetoxy group.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
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. 1,133 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Chronic kidney disease-mineral and bone disorder | 343 | 18.9 16.6–21.5ROR 18.9 · χ² 3,930 / p <1e-300 | 13.1 EB05 12.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=343 · ♀ 0% (drug 49%) | not reported in cached trials |
| Nephrogenic anaemia | 1,415 | 17.5 16.5–18.7ROR 17.6 · χ² 15,298 / p <1e-300 | 12.5 EB05 11.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=1,414 | not reported in cached trials |
| Hyperparathyroidism secondary | 746 | 16.9 15.5–18.4ROR 16.9 · χ² 7,807 / p <1e-300 | 12.1 EB05 11.4 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=745 | not reported in cached trials |
| Vascular stent thrombosis | 583 | 16.2 14.7–17.9ROR 16.3 · χ² 5,905 / p <1e-300 | 11.8 EB05 11.0 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=582 · ♀ 0% (drug 49%) · 100% clinician | not reported in cached trials |
| Coronary artery stenosis | 1,049 | 10.6 9.9–11.3ROR 10.6 · χ² 7,181 / p <1e-300 | 8.5 EB05 8.1 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=1,042 | not reported in cached trials |
| Angina unstable | 1,326 | 10.2 9.6–10.9ROR 10.2 · χ² 8,764 / p <1e-300 | 8.3 EB05 7.9 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=1,321 | not reported in cached trials |
| Systemic infection | 328 | 9.9 8.8–11.2ROR 9.9 · χ² 2,093 / p <1e-300 | 8.1 EB05 7.3 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=328 · ♀ 0% (drug 49%) · 100% clinician | not reported in cached trials |
| Thrombosis in device | 639 | 9.6 8.8–10.5ROR 9.7 · χ² 3,975 / p <1e-300 | 7.9 EB05 7.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=635 · 100% clinician | not reported in cached trials |
| Carotid artery stenosis | 675 | 9.6 8.8–10.4ROR 9.6 · χ² 4,181 / p <1e-300 | 7.9 EB05 7.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=671 | not reported in cached trials |
| Haemorrhagic anaemia | 849 | 9.5 8.8–10.2ROR 9.5 · χ² 5,192 / p <1e-300 | 7.8 EB05 7.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=849 | not reported in cached trials |
| Diverticulum intestinal haemorrhagic | 423 | 9.3 8.3–10.3ROR 9.3 · χ² 2,519 / p <1e-300 | 7.6 EB05 7.0 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=422 | not reported in cached trials |
| Aortic valve stenosis | 334 | 9.3 8.2–10.4ROR 9.3 · χ² 1,987 / p <1e-300 | 7.6 EB05 7.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=334 · ♀ 100% (drug 49%) · 100% clinician | not reported in cached trials |
| Ischaemic cardiomyopathy | 577 | 9.2 8.4–10.1ROR 9.2 · χ² 3,428 / p <1e-300 | 7.6 EB05 7.1 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=578 · ♀ 0% (drug 49%) | not reported in cached trials |
| Rebound acid hypersecretion | 570 | 9.2 8.4–10.1ROR 9.2 · χ² 3,376 / p <1e-300 | 7.6 EB05 7.1 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=570 | not reported in cached trials |
| Coronary artery disease | 5,655 | 9.2 8.9–9.4ROR 9.3 · χ² 33,481 / p <1e-300 | 7.6 EB05 7.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 | not reported in cached trials |
| Lower gastrointestinal haemorrhage | 1,273 | 8.3 7.9–8.9ROR 8.4 · χ² 6,794 / p <1e-300 | 7.1 EB05 6.7 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.7 | not reported in cached trials |
| Diastolic dysfunction | 532 | 8.3 7.6–9.2ROR 8.3 · χ² 2,834 / p <1e-300 | 7.0 EB05 6.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=527 · 100% clinician | not reported in cached trials |
| Coronary arterial stent insertion | 858 | 8.2 7.6–8.9ROR 8.2 · χ² 4,506 / p <1e-300 | 7.0 EB05 6.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=852 | not reported in cached trials |
| Coronary artery occlusion | 2,304 | 8.1 7.7–8.5ROR 8.1 · χ² 11,890 / p <1e-300 | 6.9 EB05 6.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | not reported in cached trials |
| Upper gastrointestinal haemorrhage | 2,803 | 8.0 7.7–8.4ROR 8.1 · χ² 14,344 / p <1e-300 | 6.8 EB05 6.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | not reported in cached trials |
| Coronary artery thrombosis | 336 | 8.0 7.1–9.0ROR 8.0 · χ² 1,710 / p <1e-300 | 6.8 EB05 6.2 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious n=334 · ♀ 0% (drug 49%) · 100% clinician | not reported in cached trials |
| Retroperitoneal haemorrhage | 394 | 7.6 6.9–8.5ROR 7.6 · χ² 1,902 / p <1e-300 | 6.5 EB05 6.0 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=392 · 100% clinician | not reported in cached trials |
| Essential hypertension | 411 | 7.6 6.8–8.4ROR 7.6 · χ² 1,972 / p <1e-300 | 6.5 EB05 6.0 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=383 | not reported in cached trials |
| Acute myocardial infarction | 4,590 | 7.4 7.2–7.6ROR 7.5 · χ² 21,410 / p <1e-300 | 6.4 EB05 6.2 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 | not reported in cached trials |
| Gastrointestinal haemorrhage | 12,383 | 7.0 6.8–7.1ROR 7.1 · χ² 53,950 / p <1e-300 | 6.1 EB05 6.0 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 | not reported in cached trials |
| Labelled drug-drug interaction medication error | 1,294 | 6.8 6.4–7.2ROR 6.8 · χ² 5,492 / p <1e-300 | 6.0 EB05 5.7 · IC025 +2.5 3/3 methods agree | Reporting / coding artifact | serious PRR 5.6 | not reported in cached trials |
| Carotid artery occlusion | 519 | 6.7 6.1–7.3ROR 6.7 · χ² 2,131 / p <1e-300 | 5.8 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=511 | not reported in cached trials |
| Duodenal ulcer haemorrhage | 402 | 6.6 5.9–7.3ROR 6.6 · χ² 1,618 / p <1e-300 | 5.7 EB05 5.3 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=401 · ♀ 0% (drug 49%) | not reported in cached trials |
| Ventricular hypertrophy | 352 | 6.5 5.8–7.3ROR 6.5 · χ² 1,404 / p <1e-300 | 5.7 EB05 5.2 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=350 · ♀ 0% (drug 49%) · 100% clinician | not reported in cached trials |
| Coronary artery bypass | 799 | 6.5 6.0–7.0ROR 6.5 · χ² 3,168 / p <1e-300 | 5.7 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=799 | not reported in cached trials |
| Arteriosclerosis coronary artery | 899 | 6.3 5.9–6.8ROR 6.4 · χ² 3,485 / p <1e-300 | 5.6 EB05 5.3 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=891 | not reported in cached trials |
| Mitral valve incompetence | 1,537 | 6.3 6.0–6.7ROR 6.3 · χ² 5,946 / p <1e-300 | 5.6 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | not reported in cached trials |
| End stage renal disease | 2,501 | 6.3 6.1–6.6ROR 6.4 · χ² 9,680 / p <1e-300 | 5.6 EB05 5.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | not reported in cached trials |
| Orthopnoea | 431 | 6.3 5.7–7.0ROR 6.3 · χ² 1,650 / p <1e-300 | 5.5 EB05 5.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=416 | not reported in cached trials |
| Radiculopathy | 356 | 6.3 5.6–7.0ROR 6.3 · χ² 1,361 / p 3e-298 | 5.5 EB05 5.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=352 · ♀ 100% (drug 49%) · 100% clinician | not reported in cached trials |
| Therapeutic agent toxicity | 446 | 6.1 5.5–6.8ROR 6.1 · χ² 1,651 / p <1e-300 | 5.4 EB05 5.0 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=442 | not reported in cached trials |
| Aortic stenosis | 459 | 6.1 5.5–6.7ROR 6.1 · χ² 1,696 / p <1e-300 | 5.4 EB05 5.0 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=452 | not reported in cached trials |
| Brain natriuretic peptide increased | 406 | 6.1 5.5–6.8ROR 6.1 · χ² 1,499 / p <1e-300 | 5.4 EB05 5.0 · IC025 +2.3 3/3 methods agree | Lab value / disease marker | serious n=398 · ♀ 0% (drug 49%) · 100% clinician | not reported in cached trials |
| Haemorrhagic stroke | 1,027 | 6.1 5.7–6.5ROR 6.1 · χ² 3,755 / p <1e-300 | 5.4 EB05 5.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | not reported in cached trials |
| Peripheral arterial occlusive disease | 535 | 6.0 5.5–6.6ROR 6.0 · χ² 1,947 / p <1e-300 | 5.3 EB05 5.0 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=525 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Aspirin 81 as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT02409680 — Aspirin Supplementation for Pregnancy Indicated Risk Reduction In Nulliparas (ASPIRIN) (N=11976, NA; 15 AE terms posted; arms: Intervention Arm; Placebo Arm)
- NCT02984384 — PREVENTion of Clot in Orthopaedic Trauma (N=12424, PHASE3; 7 AE terms posted; arms: Low Molecular Weight Heparin (LMWH)-Enox; Acetylsalicylic Acid (ASA)-Aspirin)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 31,779 | 1.7 1.7–1.7ROR 1.8 · χ² 9,439 / p <1e-300 | 1.7 EB05 1.7 · IC025 +0.7 | Not in label — unassessed | serious PRR 1.6 | not reported in cached trials |
| Dyspnoea (shortness of breath) | 27,147 | 2.0 2.0–2.1ROR 2.1 · χ² 13,830 / p <1e-300 | 2.0 EB05 2.0 · IC025 +1.0 | Not in label — unassessed | serious PRR 1.8 | not reported in cached trials |
| Nausea | 26,337 | 1.4 1.4–1.4ROR 1.4 · χ² 2,878 / p <1e-300 | 1.4 EB05 1.4 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.4 | not reported in cached trials |
| Diarrhoea (diarrhea) | 26,280 | 1.7 1.7–1.7ROR 1.8 · χ² 7,717 / p <1e-300 | 1.7 EB05 1.7 · IC025 +0.7 | Not in label — unassessed | serious PRR 1.5 | not reported in cached trials |
| Dizziness | 22,269 | 1.9 1.9–1.9ROR 1.9 · χ² 9,022 / p <1e-300 | 1.8 EB05 1.8 · IC025 +0.9 | Not in label — unassessed | serious PRR 1.8 | not reported in cached trials |
| Drug ineffective (drug did not work) | 21,292 | 0.7 0.7–0.7ROR 0.6 · χ² 3,889 / p <1e-300 | 0.7 EB05 0.7 · IC025 -0.6 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.9 | not reported in cached trials |
| Headache | 19,476 | 1.3 1.3–1.3ROR 1.3 · χ² 1,275 / p 1e-279 | 1.3 EB05 1.3 · IC025 +0.3 | Likely indication confounding term in indications | serious PRR 1.4 | not reported in cached trials |
| Asthenia (weakness) | 18,696 | 2.1 2.1–2.1ROR 2.1 · χ² 10,478 / p <1e-300 | 2.0 EB05 2.0 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 1.8 | not reported in cached trials |
| Off label use (used outside approved label) | 18,653 | 0.9 0.9–0.9ROR 0.9 · χ² 294 / p 4e-66 | 0.9 EB05 0.9 · IC025 -0.2 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.9 | not reported in cached trials |
| Fall | 18,443 | 2.4 2.3–2.4ROR 2.4 · χ² 13,899 / p <1e-300 | 2.3 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 2.0 | not reported in cached trials |
| Pain | 17,948 | 1.2 1.2–1.2ROR 1.2 · χ² 644 / p 2e-142 | 1.2 EB05 1.2 · IC025 +0.2 | Likely indication confounding term in indications; also in warnings | serious PRR 1.2 | not reported in cached trials |
| Pneumonia (lung infection) | 15,853 | 2.1 2.0–2.1ROR 2.1 · χ² 8,515 / p <1e-300 | 2.0 EB05 2.0 · IC025 +1.0 | Not in label — unassessed | serious PRR 1.7 | not reported in cached trials |
| Vomiting | 15,825 | 1.4 1.4–1.4ROR 1.4 · χ² 1,823 / p <1e-300 | 1.4 EB05 1.4 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.4 | not reported in cached trials |
| Death | 14,498 | 0.7 0.7–0.7ROR 0.7 · χ² 2,096 / p <1e-300 | 0.7 EB05 0.7 · IC025 -0.6 PRR-only: not supported by EBGM or IC | Outcome field, not a reaction | serious PRR 0.6 | NCT02409680: 9/5,943 (0.2%) on Aspirin 81; 12/5,936 (0.2%) control (serious AE) |
| Myocardial infarction (heart attack) | 14,366 | 3.6 3.5–3.6ROR 3.7 · χ² 24,710 / p <1e-300 | 3.4 EB05 3.3 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | not reported in cached trials |
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.
- Chronic kidney disease-mineral and bone disorder — n=343, PRR 18.9
- Nephrogenic anaemia — n=1,415, PRR 17.5
- Hyperparathyroidism secondary — n=746, PRR 16.9
- Vascular stent thrombosis — n=583, PRR 16.2
- Coronary artery stenosis — n=1,049, PRR 10.6
- Angina unstable — n=1,326, PRR 10.2
- Systemic infection — n=328, PRR 9.9
- Thrombosis in device — n=639, PRR 9.6
- Carotid artery stenosis — n=675, PRR 9.6
- Haemorrhagic anaemia — n=849, PRR 9.5
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 Aspirin 81?
In FDA FAERS, the most frequently co-reported reaction terms for Aspirin 81 are fatigue, dyspnoea, nausea, diarrhoea, dizziness, headache. 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 Aspirin 81 have an FDA boxed warning?
No. The FDA label retrieved for Aspirin 81 has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Aspirin 81 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 04017bc9-602a-4204-96a9-b7f9713155f6, effective 20230131; matched on
openfda.generic_name.exact:"ASPIRIN 81 MG") - PubChem CID 2244 description (ChEBI)
- 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, 1,173 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
ASPIRIN 81, 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.