Amoxicillin side effects: what 75,882 FDA adverse event reports show
Drug class
Not stated in label
Who reports
75,882 reports · 80% serious · 5,023 with death outcome · 60% female
Used for
Adults and Pediatric Patients Upper Respiratory Tract Infections of the Ear, Nose, and Throat: Amoxicillin capsules are indicated in the treatment of infections due to susceptible (ONLY β- lactamase–negative) isolates of Streptococcus species. (α- and β-hemolytic isolates only), Streptococcus pneumoniae , Staphylococcus spp., or Haemophilus influenzae .
What it is
Amoxicillin capsules, USP are a semisynthetic antibacterial (amoxicillin), an analog of ampicillin, with a broad spectrum of bactericidal activity against many Gram-positive and Gram-negative microorganisms.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
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.
- 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. 1,168 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 |
|---|---|---|---|---|---|---|
| Amyloid arthropathy | 59 | 3,204.4 1,286.1–7,983.7ROR 3,206.8 · χ² 14,511 / p <1e-300 | 232.4 EB05 186.8 · IC025 +5.9 3/3 methods agree | Not in label — unassessed | serious n=59 · ♀ 100% (drug 60%) · 100% clinician | not reported in cached trials |
| Vaginal flatulence | 146 | 254.1 202.8–318.5ROR 254.6 · χ² 18,886 / p <1e-300 | 129.6 EB05 112.9 · IC025 +6.2 3/3 methods agree | Not in label — unassessed | serious n=146 · ♀ 100% (drug 60%) | not reported in cached trials |
| Allergy test positive | 106 | 87.0 69.9–108.2ROR 87.1 · χ² 6,757 / p <1e-300 | 65.4 EB05 55.6 · IC025 +5.3 3/3 methods agree | Lab value / disease marker | serious n=106 · 100% clinician | not reported in cached trials |
| Crystalluria | 119 | 76.8 62.6–94.1ROR 76.9 · χ² 6,878 / p <1e-300 | 59.5 EB05 51.1 · IC025 +5.3 3/3 methods agree | Labeled adverse reaction exact term | serious n=119 · 100% clinician | not reported in cached trials |
| Chronic kidney disease-mineral and bone disorder | 185 | 57.3 48.9–67.1ROR 57.4 · χ² 8,402 / p <1e-300 | 47.3 EB05 41.8 · IC025 +5.2 3/3 methods agree | Not in label — unassessed | serious n=185 | not reported in cached trials |
| Therapeutic product cross-reactivity | 152 | 55.7 46.8–66.3ROR 55.8 · χ² 6,731 / p <1e-300 | 46.1 EB05 40.3 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=152 · 100% clinician | not reported in cached trials |
| Rebound acid hypersecretion | 440 | 46.2 41.8–51.1ROR 46.4 · χ² 16,588 / p <1e-300 | 39.6 EB05 36.5 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=440 | not reported in cached trials |
| Nephrogenic anaemia | 661 | 45.4 41.8–49.3ROR 45.8 · χ² 24,562 / p <1e-300 | 39.0 EB05 36.6 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=661 | not reported in cached trials |
| Hyperparathyroidism secondary | 343 | 43.2 38.6–48.4ROR 43.4 · χ² 12,164 / p <1e-300 | 37.3 EB05 34.1 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=343 | not reported in cached trials |
| Serum sickness-like reaction | 81 | 42.1 33.3–53.1ROR 42.1 · χ² 2,776 / p <1e-300 | 36.3 EB05 30.1 · IC025 +4.5 3/3 methods agree | Labeled adverse reaction exact term | serious n=48 · 100% clinician | not reported in cached trials |
| Type i hypersensitivity | 392 | 34.8 31.4–38.7ROR 35.0 · χ² 11,386 / p <1e-300 | 30.9 EB05 28.4 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=392 · 100% clinician | not reported in cached trials |
| Pulmonary vasculitis | 57 | 33.3 25.3–43.8ROR 33.3 · χ² 1,561 / p <1e-300 | 29.5 EB05 23.6 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=57 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Spirometry abnormal | 61 | 31.9 24.5–41.6ROR 31.9 · χ² 1,607 / p <1e-300 | 28.4 EB05 22.9 · IC025 +4.1 3/3 methods agree | Lab value / disease marker | serious n=61 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Mite allergy | 65 | 31.2 24.2–40.4ROR 31.3 · χ² 1,679 / p <1e-300 | 27.9 EB05 22.7 · IC025 +4.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=65 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Female genital tract fistula | 174 | 31.0 26.5–36.2ROR 31.1 · χ² 4,505 / p <1e-300 | 27.8 EB05 24.5 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=174 · ♀ 100% (drug 60%) | not reported in cached trials |
| Crystal nephropathy | 55 | 28.5 21.6–37.6ROR 28.5 · χ² 1,296 / p 4e-284 | 25.7 EB05 20.5 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=55 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Symmetrical drug-related intertriginous and flexural exanthema | 60 | 22.5 17.3–29.3ROR 22.6 · χ² 1,120 / p 6e-246 | 20.8 EB05 16.7 · IC025 +3.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=60 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| End stage renal disease | 1,392 | 22.5 21.3–23.8ROR 22.9 · χ² 26,436 / p <1e-300 | 20.9 EB05 20.0 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 14.9 | not reported in cached trials |
| Radiculopathy | 198 | 22.4 19.3–25.8ROR 22.4 · χ² 3,713 / p <1e-300 | 20.7 EB05 18.4 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=198 · ♀ 88% (drug 60%) | not reported in cached trials |
| Skin test positive | 69 | 21.8 17.0–27.8ROR 21.8 · χ² 1,246 / p 3e-273 | 20.1 EB05 16.4 · IC025 +3.8 3/3 methods agree | Lab value / disease marker | serious n=67 · 100% clinician | not reported in cached trials |
| Chronic sinusitis | 272 | 21.6 19.1–24.4ROR 21.6 · χ² 4,922 / p <1e-300 | 20.0 EB05 18.1 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=263 · ♀ 87% (drug 60%) | not reported in cached trials |
| Enterocolitis haemorrhagic | 103 | 20.5 16.8–25.0ROR 20.5 · χ² 1,758 / p <1e-300 | 19.1 EB05 16.2 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious n=102 · 100% clinician | not reported in cached trials |
| Dust allergy | 66 | 20.2 15.8–26.0ROR 20.2 · χ² 1,105 / p 1e-242 | 18.8 EB05 15.3 · IC025 +3.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=66 · ♀ 0% (drug 60%) | not reported in cached trials |
| Mycotic allergy | 57 | 20.0 15.3–26.1ROR 20.0 · χ² 939 / p 1e-206 | 18.6 EB05 14.8 · IC025 +3.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=57 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Type iv hypersensitivity reaction | 168 | 18.1 15.5–21.2ROR 18.1 · χ² 2,529 / p <1e-300 | 17.0 EB05 14.9 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=162 · 100% clinician | not reported in cached trials |
| Chronic kidney disease | 4,668 | 17.9 17.4–18.4ROR 19.0 · χ² 69,951 / p <1e-300 | 16.8 EB05 16.4 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 12.2 | not reported in cached trials |
| Lip oedema | 251 | 17.3 15.2–19.7ROR 17.4 · χ² 3,610 / p <1e-300 | 16.3 EB05 14.7 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious n=246 · 100% clinician | not reported in cached trials |
| Proctitis | 163 | 17.0 14.5–19.9ROR 17.0 · χ² 2,294 / p <1e-300 | 16.0 EB05 14.0 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=162 · ♀ 100% (drug 60%) | not reported in cached trials |
| Fixed eruption | 95 | 16.4 13.3–20.1ROR 16.4 · χ² 1,278 / p 4e-280 | 15.4 EB05 13.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=89 · ♀ 34% (drug 60%) · 100% clinician | not reported in cached trials |
| Acute generalised exanthematous pustulosis | 421 | 15.8 14.4–17.5ROR 15.9 · χ² 5,521 / p <1e-300 | 15.0 EB05 13.8 · IC025 +3.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.8 · 95% clinician | not reported in cached trials |
| Meningitis aseptic | 238 | 15.5 13.6–17.6ROR 15.5 · χ² 3,034 / p <1e-300 | 14.7 EB05 13.2 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious n=238 · 100% clinician | not reported in cached trials |
| Rash morbilliform | 138 | 14.4 12.2–17.1ROR 14.4 · χ² 1,624 / p <1e-300 | 13.7 EB05 11.9 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=130 | not reported in cached trials |
| Allergy to chemicals | 61 | 14.2 11.0–18.3ROR 14.2 · χ² 698 / p 4e-154 | 13.4 EB05 10.7 · IC025 +3.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=60 · ♀ 100% (drug 60%) · 100% clinician | not reported in cached trials |
| Conjunctivitis allergic | 64 | 12.6 9.8–16.2ROR 12.6 · χ² 642 / p 7e-142 | 11.9 EB05 9.5 · IC025 +3.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=61 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Mixed liver injury | 124 | 12.2 10.2–14.7ROR 12.3 · χ² 1,215 / p 2e-266 | 11.7 EB05 10.0 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=124 · 100% clinician | not reported in cached trials |
| Rash maculo-papular | 929 | 12.0 11.3–12.9ROR 12.2 · χ² 9,011 / p <1e-300 | 11.6 EB05 11.0 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious PRR 9.0 · 94% clinician | not reported in cached trials |
| Tubulointerstitial nephritis | 775 | 11.9 11.1–12.8ROR 12.0 · χ² 7,397 / p <1e-300 | 11.4 EB05 10.7 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious PRR 8.2 | not reported in cached trials |
| Vascular purpura | 56 | 11.5 8.8–15.1ROR 11.6 · χ² 507 / p 1e-112 | 10.8 EB05 8.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=56 · ♀ 0% (drug 60%) · 100% clinician | not reported in cached trials |
| Linear iga disease | 67 | 11.5 9.0–14.7ROR 11.6 · χ² 609 / p 1e-134 | 10.9 EB05 8.8 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=67 · ♀ 100% (drug 60%) · 100% clinician | not reported in cached trials |
| Neuritis | 61 | 11.4 8.8–14.7ROR 11.4 · χ² 543 / p 2e-120 | 10.7 EB05 8.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=60 · ♀ 0% (drug 60%) | 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 Amoxicillin 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).
- NCT05584657 — Oral Sulopenem Versus Amoxicillin/Clavulanate for Uncomplicated Urinary Tract Infection in Adult Women (N=2229, PHASE3; 10 AE terms posted; arms: Sulopenem Etzadroxil/Probenecid; Amoxicillin/Clavulanate)
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 |
|---|---|---|---|---|---|---|
| Chronic kidney disease | 4,668 | 17.9 17.4–18.4ROR 19.0 · χ² 69,951 / p <1e-300 | 16.8 EB05 16.4 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 12.2 | not reported in cached trials |
| Acute kidney injury (sudden kidney damage) | 4,276 | 8.0 7.7–8.2ROR 8.4 · χ² 25,427 / p <1e-300 | 7.7 EB05 7.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.6 | not reported in cached trials |
| Diarrhoea (diarrhea) | 4,218 | 1.8 1.8–1.9ROR 1.9 · χ² 1,586 / p <1e-300 | 1.8 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.8 | NCT05584657: 45/1,107 (4.1%) on Amoxicillin |
| Nausea | 3,807 | 1.3 1.3–1.4ROR 1.4 · χ² 330 / p 6e-74 | 1.3 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.5 | NCT05584657: 48/1,107 (4.3%) on Amoxicillin |
| Drug hypersensitivity | 3,806 | 5.5 5.3–5.7ROR 5.7 · χ² 13,866 / p <1e-300 | 5.4 EB05 5.3 · IC025 +2.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.3 | not reported in cached trials |
| Dyspnoea (shortness of breath) | 3,720 | 1.8 1.8–1.9ROR 1.9 · χ² 1,408 / p <1e-300 | 1.8 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 1.6 | not reported in cached trials |
| Rash | 3,674 | 2.4 2.3–2.4ROR 2.4 · χ² 2,889 / p <1e-300 | 2.3 EB05 2.3 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.7 | not reported in cached trials |
| Pain | 3,638 | 1.6 1.6–1.7ROR 1.7 · χ² 923 / p 6e-203 | 1.6 EB05 1.6 · IC025 +0.7 | Not in label — unassessed | serious PRR 1.6 | NCT05584657: 1/1,107 (0.1%) on Amoxicillin (serious AE) |
| Fatigue (tiredness) | 3,378 | 1.2 1.2–1.2ROR 1.2 · χ² 118 / p 8e-28 | 1.2 EB05 1.2 · IC025 +0.2 | Not in label — unassessed | serious PRR 1.2 | not reported in cached trials |
| Drug ineffective (drug did not work) | 3,083 | 0.6 0.6–0.7ROR 0.6 · χ² 637 / p 9e-141 | 0.6 EB05 0.6 · IC025 -0.7 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.0 | not reported in cached trials |
| Renal failure (kidney failure) | 3,067 | 6.5 6.2–6.7ROR 6.7 · χ² 13,905 / p <1e-300 | 6.3 EB05 6.1 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.6 | not reported in cached trials |
| Off label use (used outside approved label) | 3,057 | 1.0 0.9–1.0ROR 1.0 · χ² 2 / p 0.061 | 1.0 EB05 0.9 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.1 | not reported in cached trials |
| Vomiting | 2,951 | 1.7 1.7–1.8ROR 1.8 · χ² 950 / p 8e-209 | 1.7 EB05 1.7 · IC025 +0.7 | Labeled adverse reaction exact term | serious PRR 1.6 | NCT05584657: 4/1,107 (0.4%) on Amoxicillin |
| Headache | 2,901 | 1.3 1.2–1.3ROR 1.3 · χ² 183 / p 5e-42 | 1.3 EB05 1.2 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.5 | NCT05584657: 17/1,107 (1.5%) on Amoxicillin |
| Pruritus (itching) | 2,884 | 2.1 2.0–2.2ROR 2.2 · χ² 1,715 / p <1e-300 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 | 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.
- Amyloid arthropathy — n=59, PRR 3,204.4
- Vaginal flatulence — n=146, PRR 254.1
- Chronic kidney disease-mineral and bone disorder — n=185, PRR 57.3
- Therapeutic product cross-reactivity — n=152, PRR 55.7
- Rebound acid hypersecretion — n=440, PRR 46.2
- Nephrogenic anaemia — n=661, PRR 45.4
- Hyperparathyroidism secondary — n=343, PRR 43.2
- Type i hypersensitivity — n=392, PRR 34.8
- Pulmonary vasculitis — n=57, PRR 33.3
- Female genital tract fistula — n=174, PRR 31.0
✓ A hand-written Bradford Hill causality assessment exists for this drug: Amoxicillin–clavulanate ↔ Cholestatic liver injury.
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 Amoxicillin?
In FDA FAERS, the most frequently co-reported reaction terms for Amoxicillin are chronic kidney disease, acute kidney injury, diarrhoea, nausea, drug hypersensitivity, dyspnoea. 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 Amoxicillin have an FDA boxed warning?
No. The FDA label retrieved for Amoxicillin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Amoxicillin 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 05e88717-2ce3-4b1a-88af-c3f61a2d8cd5, effective 20241104; matched on
openfda.generic_name.exact:"AMOXICILLIN") - 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, 1,208 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
AMOXICILLIN, 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.