Buffered Aspirin side effects: what 1,404 FDA adverse event reports show

Buffered Aspirin · Alka-Seltzer · 43 reaction terms · 2,674 drug–reaction co-reports · data 2026-09-14

Drug class

Nonsteroidal Anti-inflammatory Drug, Platelet Aggregation Inhibitor

FDA label (Established Pharmacologic Class) · compare the class

Brand names

Alka-Seltzer

openFDA label

Who reports

1,404 reports · 81% serious · 114 with death outcome · 57% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Uses temporarily relieves minor aches and pains due to: headache muscle pain backache toothache menstrual pain colds minor pain of arthritis 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 28 strongest signals

Labeled (related wording) 2Likely indication confounding 1Lab value / disease marker 1Not in label — unassessed 24

What the badges mean

Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
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.
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. 15 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
End stage renal disease	256	210.5 188.3–235.4ROR 257.2 · χ² 52,468 / p <1e-300	204.4 EB05 184.2 · IC025 +7.0 3/3 methods agree	Not in label — unassessed	serious PRR 146.6	no trial data cached
Chronic kidney disease	721	141.8 134.7–149.3ROR 290.5 · χ² 100,083 / p <1e-300	140.0 EB05 131.6 · IC025 +6.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 100.9	no trial data cached
Renal injury	179	89.6 78.1–102.8ROR 102.5 · χ² 15,519 / p <1e-300	88.2 EB05 77.9 · IC025 +5.9 3/3 methods agree	Not in label — unassessed	serious PRR 63.1	no trial data cached
Nephropathy	35	55.9 40.3–77.6ROR 57.3 · χ² 1,827 / p <1e-300	54.1 EB05 40.7 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 42.0	no trial data cached
Tubulointerstitial nephritis	64	51.2 40.3–65.1ROR 53.6 · χ² 3,092 / p <1e-300	50.3 EB05 40.8 · IC025 +4.8 3/3 methods agree	Not in label — unassessed	serious PRR 36.2	no trial data cached
Renal failure (kidney failure)	395	44.2 40.7–48.1ROR 61.2 · χ² 16,703 / p <1e-300	44.0 EB05 40.5 · IC025 +5.2 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.4	no trial data cached
Acute kidney injury (sudden kidney damage)	439	43.2 39.9–46.7ROR 62.4 · χ² 18,121 / p <1e-300	43.0 EB05 39.7 · IC025 +5.2 3/3 methods agree	Not in label — unassessed	serious PRR 30.5	no trial data cached
Multiple fractures	45	40.7 30.5–54.2ROR 42.0 · χ² 1,698 / p <1e-300	39.9 EB05 31.1 · IC025 +4.3 3/3 methods agree	Not in label — unassessed	serious PRR 28.5 · ♀ 77% (drug 57%)	no trial data cached
Vitamin d deficiency	24	36.9 24.8–54.8ROR 37.5 · χ² 800 / p 2e-176	35.8 EB05 25.3 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 27.4 · ♀ 92% (drug 57%)	no trial data cached
Intervertebral disc degeneration	17	27.3 17.0–43.9ROR 27.6 · χ² 405 / p 3e-90	26.5 EB05 17.5 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 22.1	no trial data cached
Osteoporosis	68	24.7 19.6–31.2ROR 25.9 · χ² 1,523 / p <1e-300	24.5 EB05 20.0 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 19.0 · ♀ 78% (drug 57%)	no trial data cached
Gastrooesophageal reflux disease (acid reflux)	118	22.0 18.5–26.2ROR 23.9 · χ² 2,351 / p <1e-300	21.9 EB05 18.8 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 24.4	no trial data cached
Bone disorder	26	21.2 14.5–31.0ROR 21.5 · χ² 479 / p 2e-106	20.8 EB05 14.9 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 17.5	no trial data cached
Arteriosclerosis	11	17.4 9.7–31.4ROR 17.6 · χ² 154 / p 1e-35	16.2 EB05 8.7 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 12.7	no trial data cached
Full blood count abnormal	11	15.6 8.7–28.1ROR 15.7 · χ² 136 / p 1e-31	14.2 EB05 7.4 · IC025 +2.2 3/3 methods agree	Lab value / disease marker	serious PRR 14.6	no trial data cached
Ankle fracture	16	15.4 9.5–25.1ROR 15.6 · χ² 202 / p 5e-46	14.7 EB05 9.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 12.3	no trial data cached
Renal tubular necrosis	10	15.2 8.2–28.2ROR 15.3 · χ² 119 / p 6e-28	13.5 EB05 6.7 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 10.8	no trial data cached
Carpal tunnel syndrome	12	12.8 7.3–22.4ROR 12.9 · χ² 119 / p 6e-28	11.2 EB05 6.1 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 10.2	no trial data cached
Wrist fracture	10	12.5 6.7–23.1ROR 12.5 · χ² 94 / p 1e-22	10.4 EB05 5.3 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 10.3	no trial data cached
Nodule	10	11.5 6.2–21.2ROR 11.5 · χ² 85 / p 1e-20	9.4 EB05 4.8 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 12.5	no trial data cached
Sleep disorder due to a general medical condition	12	11.1 6.3–19.5ROR 11.2 · χ² 100 / p 7e-24	9.4 EB05 5.2 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 15.5	no trial data cached
Osteopenia	11	10.8 6.0–19.4ROR 10.9 · χ² 88 / p 3e-21	8.9 EB05 4.8 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 9.0	no trial data cached
Foot fracture	13	10.2 5.9–17.6ROR 10.3 · χ² 99 / p 1e-23	8.6 EB05 5.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.6	no trial data cached
Arthritis	48	9.1 6.9–12.0ROR 9.4 · χ² 339 / p 5e-76	8.7 EB05 6.7 · IC025 +2.6 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 9.4	no trial data cached
Intervertebral disc protrusion	13	8.9 5.2–15.2ROR 8.9 · χ² 83 / p 4e-20	7.3 EB05 4.4 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 6.8	no trial data cached
Glaucoma	11	8.5 4.7–15.4ROR 8.6 · χ² 66 / p 2e-16	6.8 EB05 3.9 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.3	no trial data cached
Lower limb fracture	10	7.8 4.2–14.5ROR 7.9 · χ² 53 / p 2e-13	6.1 EB05 3.5 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 5.5	no trial data cached
Angina pectoris	12	6.2 3.5–10.9ROR 6.3 · χ² 47 / p 3e-12	5.1 EB05 3.1 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 3.8	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
Chronic kidney disease	721	141.8 134.7–149.3ROR 290.5 · χ² 100,083 / p <1e-300	140.0 EB05 131.6 · IC025 +6.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 100.9	no trial data cached
Acute kidney injury (sudden kidney damage)	439	43.2 39.9–46.7ROR 62.4 · χ² 18,121 / p <1e-300	43.0 EB05 39.7 · IC025 +5.2 3/3 methods agree	Not in label — unassessed	serious PRR 30.5	no trial data cached
Renal failure (kidney failure)	395	44.2 40.7–48.1ROR 61.2 · χ² 16,703 / p <1e-300	44.0 EB05 40.5 · IC025 +5.2 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.4	no trial data cached
End stage renal disease	256	210.5 188.3–235.4ROR 257.2 · χ² 52,468 / p <1e-300	204.4 EB05 184.2 · IC025 +7.0 3/3 methods agree	Not in label — unassessed	serious PRR 146.6	no trial data cached
Renal injury	179	89.6 78.1–102.8ROR 102.5 · χ² 15,519 / p <1e-300	88.2 EB05 77.9 · IC025 +5.9 3/3 methods agree	Not in label — unassessed	serious PRR 63.1	no trial data cached
Gastrooesophageal reflux disease (acid reflux)	118	22.0 18.5–26.2ROR 23.9 · χ² 2,351 / p <1e-300	21.9 EB05 18.8 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 24.4	no trial data cached
Osteoporosis	68	24.7 19.6–31.2ROR 25.9 · χ² 1,523 / p <1e-300	24.5 EB05 20.0 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 19.0 · ♀ 78% (drug 57%)	no trial data cached
Tubulointerstitial nephritis	64	51.2 40.3–65.1ROR 53.6 · χ² 3,092 / p <1e-300	50.3 EB05 40.8 · IC025 +4.8 3/3 methods agree	Not in label — unassessed	serious PRR 36.2	no trial data cached
Arthritis	48	9.1 6.9–12.0ROR 9.4 · χ² 339 / p 5e-76	8.7 EB05 6.7 · IC025 +2.6 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 9.4	no trial data cached
Multiple fractures	45	40.7 30.5–54.2ROR 42.0 · χ² 1,698 / p <1e-300	39.9 EB05 31.1 · IC025 +4.3 3/3 methods agree	Not in label — unassessed	serious PRR 28.5 · ♀ 77% (drug 57%)	no trial data cached
Nephropathy	35	55.9 40.3–77.6ROR 57.3 · χ² 1,827 / p <1e-300	54.1 EB05 40.7 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 42.0	no trial data cached
Bone disorder	26	21.2 14.5–31.0ROR 21.5 · χ² 479 / p 2e-106	20.8 EB05 14.9 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 17.5	no trial data cached
Vitamin d deficiency	24	36.9 24.8–54.8ROR 37.5 · χ² 800 / p 2e-176	35.8 EB05 25.3 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 27.4 · ♀ 92% (drug 57%)	no trial data cached
Intervertebral disc degeneration	17	27.3 17.0–43.9ROR 27.6 · χ² 405 / p 3e-90	26.5 EB05 17.5 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 22.1	no trial data cached
Ankle fracture	16	15.4 9.5–25.1ROR 15.6 · χ² 202 / p 5e-46	14.7 EB05 9.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 12.3	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.

End stage renal disease — n=256, PRR 210.5
Renal injury — n=179, PRR 89.6
Nephropathy — n=35, PRR 55.9
Tubulointerstitial nephritis — n=64, PRR 51.2
Acute kidney injury — n=439, PRR 43.2
Multiple fractures — n=45, PRR 40.7
Vitamin d deficiency — n=24, PRR 36.9
Osteoporosis — n=68, PRR 24.7
Gastrooesophageal reflux disease — n=118, PRR 22.0
Bone disorder — n=26, PRR 21.2

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 Buffered Aspirin?

In FDA FAERS, the most frequently co-reported reaction terms for Buffered Aspirin are chronic kidney disease, acute kidney injury, renal failure, end stage renal disease, renal injury, gastrooesophageal reflux disease. 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 Buffered Aspirin have an FDA boxed warning?

No. The FDA label retrieved for Buffered Aspirin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Buffered Aspirin 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 0c7a60e7-0bde-9aa2-e063-6294a90a3209, effective 20231214; matched on openfda.generic_name.exact:"BUFFERED ASPIRIN")
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, 43 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.