Amoxicillin and Clavulanate side effects: what 27,008 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Amoxicillin (Amoxicillin)
Who reports
27,008 reports · 78% serious · 2,605 with death outcome · 57% 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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,182 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 |
|---|---|---|---|---|---|---|
| Spirometry abnormal | 65 | 96.5 74.6–124.9ROR 96.8 · calibrated p 2e-7 ✓ | 83.8 EB05 68.0 · IC025 +5.3 3/3 methods agree | Lab value / disease marker | serious n=65 · ♀ 0% (drug 57%) | not reported in cached trials |
| Mite allergy | 70 | 95.6 74.6–122.5ROR 95.9 · calibrated p 2e-7 ✓ | 83.2 EB05 68.1 · IC025 +5.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=70 · ♀ 0% (drug 57%) | not reported in cached trials |
| Mycotic allergy | 69 | 69.2 54.1–88.5ROR 69.3 · calibrated p 2e-6 ✓ | 62.5 EB05 51.0 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=69 · ♀ 0% (drug 57%) | not reported in cached trials |
| Dust allergy | 70 | 60.7 47.6–77.4ROR 60.9 · calibrated p 5e-6 ✓ | 55.5 EB05 45.4 · IC025 +4.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=70 · ♀ 0% (drug 57%) | not reported in cached trials |
| Pulmonary vasculitis | 32 | 49.9 34.9–71.4ROR 50.0 · calibrated p 2e-5 ✓ | 45.8 EB05 33.9 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=32 · ♀ 0% (drug 57%) · 100% clinician | not reported in cached trials |
| Total lung capacity abnormal | 22 | 47.5 30.9–73.1ROR 47.6 · calibrated p 4e-5 ✓ | 43.3 EB05 30.1 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=22 · ♀ 0% (drug 57%) | not reported in cached trials |
| Mixed liver injury | 148 | 41.5 35.2–49.0ROR 41.8 · calibrated p 5e-5 ✓ | 39.3 EB05 34.2 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=147 · 100% clinician | not reported in cached trials |
| Conjunctivitis allergic | 70 | 39.0 30.7–49.5ROR 39.1 · calibrated p 8e-5 ✓ | 36.8 EB05 30.1 · IC025 +4.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=69 · ♀ 0% (drug 57%) | not reported in cached trials |
| Respiratory tract infection bacterial | 21 | 34.0 21.9–52.6ROR 34.0 · calibrated p 3e-4 ✓ | 31.7 EB05 21.9 · IC025 +3.5 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=21 · 100% clinician | not reported in cached trials |
| Sputum purulent | 26 | 31.7 21.4–46.9ROR 31.7 · calibrated p 3e-4 ✓ | 29.9 EB05 21.4 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=26 · ♀ 0% (drug 57%) | not reported in cached trials |
| Vascular purpura | 53 | 30.7 23.3–40.4ROR 30.8 · calibrated p 3e-4 ✓ | 29.3 EB05 23.2 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=53 · ♀ 37% (drug 57%) | not reported in cached trials |
| Hepatitis cholestatic | 223 | 29.9 26.2–34.2ROR 30.2 · calibrated p 3e-4 ✓ | 28.8 EB05 25.8 · IC025 +4.5 3/3 methods agree | Labeled (related wording) related wording | serious n=213 | not reported in cached trials |
| Antineutrophil cytoplasmic antibody positive | 26 | 28.7 19.4–42.4ROR 28.7 · calibrated p 5e-4 ✓ | 27.2 EB05 19.5 · IC025 +3.5 3/3 methods agree | Lab value / disease marker | serious n=26 · ♀ 0% (drug 57%) · 100% clinician | not reported in cached trials |
| Chronic kidney disease-mineral and bone disorder | 33 | 24.5 17.3–34.7ROR 24.6 · calibrated p 0.001 ✓ | 23.5 EB05 17.5 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=33 | not reported in cached trials |
| Cholestasis (bile flow blockage) | 563 | 23.6 21.7–25.6ROR 24.0 · calibrated p 8e-4 ✓ | 22.9 EB05 21.3 · IC025 +4.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 16.9 | not reported in cached trials |
| Normochromic normocytic anaemia | 88 | 23.4 18.9–28.9ROR 23.5 · calibrated p 0.001 ✓ | 22.6 EB05 18.9 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=88 · ♀ 0% (drug 57%) | not reported in cached trials |
| Choroidal effusion | 22 | 21.9 14.4–33.5ROR 22.0 · calibrated p 0.002 ✓ | 21.0 EB05 14.5 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=22 · 100% clinician | not reported in cached trials |
| Neuritis | 39 | 20.2 14.7–27.7ROR 20.2 · calibrated p 0.002 ✓ | 19.5 EB05 14.8 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=39 · ♀ 0% (drug 57%) | not reported in cached trials |
| Hepatocellular injury | 358 | 20.0 18.0–22.2ROR 20.3 · calibrated p 0.002 ✓ | 19.5 EB05 17.9 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 14.5 | not reported in cached trials |
| Acute generalised exanthematous pustulosis | 192 | 19.7 17.1–22.8ROR 19.9 · calibrated p 0.002 ✓ | 19.2 EB05 17.0 · IC025 +4.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 14.3 | not reported in cached trials |
| Cell death | 49 | 19.6 14.8–26.0ROR 19.6 · calibrated p 0.003 ✓ | 19.0 EB05 14.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=48 · ♀ 33% (drug 57%) · 100% clinician | not reported in cached trials |
| Cholestatic liver injury | 52 | 19.3 14.6–25.4ROR 19.3 · calibrated p 0.003 ✓ | 18.7 EB05 14.8 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=52 · ♀ 33% (drug 57%) · 100% clinician | not reported in cached trials |
| Toxic skin eruption | 243 | 19.1 16.8–21.7ROR 19.3 · calibrated p 0.002 ✓ | 18.6 EB05 16.7 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious PRR 13.9 | not reported in cached trials |
| Primary sequestrum | 22 | 19.0 12.5–29.1ROR 19.0 · calibrated p 0.004 ✓ | 18.2 EB05 12.5 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=22 | not reported in cached trials |
| Prothrombin time shortened | 31 | 17.5 12.3–25.0ROR 17.5 · calibrated p 0.005 ✓ | 16.9 EB05 12.4 · IC025 +3.2 3/3 methods agree | Lab value / disease marker | serious n=31 · 100% clinician | not reported in cached trials |
| Acute sinusitis | 38 | 17.5 12.7–24.1ROR 17.5 · calibrated p 0.004 ✓ | 16.9 EB05 12.8 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=35 | not reported in cached trials |
| Jaundice cholestatic | 77 | 17.2 13.8–21.6ROR 17.3 · calibrated p 0.004 ✓ | 16.8 EB05 13.9 · IC025 +3.6 3/3 methods agree | Labeled (related wording) related wording | serious n=76 | not reported in cached trials |
| Clostridium colitis | 25 | 16.2 10.9–24.0ROR 16.2 · calibrated p 0.007 ✓ | 15.5 EB05 10.8 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=23 | not reported in cached trials |
| Rash maculo-papular | 430 | 15.3 14.0–16.9ROR 15.6 · calibrated p 0.006 ✓ | 15.0 EB05 13.9 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 12.3 | not reported in cached trials |
| Hepatic cytolysis | 231 | 14.9 13.1–17.0ROR 15.1 · calibrated p 0.007 ✓ | 14.6 EB05 13.1 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious PRR 10.9 · 100% clinician | not reported in cached trials |
| Rash morbilliform | 52 | 14.8 11.3–19.5ROR 14.8 · calibrated p 0.008 ✓ | 14.4 EB05 11.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=52 | not reported in cached trials |
| Palatal oedema | 23 | 14.6 9.6–22.0ROR 14.6 · calibrated p 0.011 ✓ | 13.8 EB05 9.3 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=23 · 100% clinician | not reported in cached trials |
| Eosinophilic granulomatosis with polyangiitis | 36 | 14.1 10.1–19.6ROR 14.1 · calibrated p 0.011 ✓ | 13.5 EB05 10.0 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=36 · ♀ 0% (drug 57%) · 100% clinician | not reported in cached trials |
| Osteosclerosis | 28 | 14.0 9.6–20.4ROR 14.0 · calibrated p 0.012 ✓ | 13.4 EB05 9.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=28 · 100% consumer | not reported in cached trials |
| Dermatitis exfoliative generalised | 59 | 13.5 10.5–17.5ROR 13.6 · calibrated p 0.012 ✓ | 13.1 EB05 10.5 · IC025 +3.2 3/3 methods agree | Labeled (related wording) related wording | serious n=59 · 100% clinician | not reported in cached trials |
| Hyperparathyroidism secondary | 43 | 13.4 9.9–18.1ROR 13.4 · calibrated p 0.013 ✓ | 12.9 EB05 9.8 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=43 | not reported in cached trials |
| Osteolysis | 34 | 13.1 9.3–18.3ROR 13.1 · calibrated p 0.015 ✓ | 12.5 EB05 9.1 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=34 | not reported in cached trials |
| Nephrogenic anaemia | 77 | 13.0 10.4–16.3ROR 13.0 · calibrated p 0.013 ✓ | 12.6 EB05 10.4 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=77 | not reported in cached trials |
| Infusion site discharge | 28 | 12.9 8.9–18.7ROR 12.9 · calibrated p 0.016 ✓ | 12.2 EB05 8.6 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=28 · ♀ 100% (drug 57%) · 100% consumer | not reported in cached trials |
| Biliary tract disorder | 22 | 12.6 8.3–19.2ROR 12.6 · calibrated p 0.018 ✓ | 11.7 EB05 7.7 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | – | 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 and Clavulanate 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 |
|---|---|---|---|---|---|---|
| Diarrhoea (diarrhea) | 1,880 | 2.3 2.2–2.4ROR 2.4 · calibrated p 0.872 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | NCT05584657: 45/1,107 (4.1%) on Amoxicillin and Clavulanate |
| Drug hypersensitivity | 1,818 | 7.3 7.0–7.7ROR 7.8 · calibrated p 0.072 | 7.3 EB05 7.0 · IC025 +2.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.0 · ♀ 82% (drug 57%) | not reported in cached trials |
| Nausea | 1,436 | 1.4 1.3–1.5ROR 1.4 · calibrated p 0.600 | 1.4 EB05 1.4 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.4 | NCT05584657: 48/1,107 (4.3%) on Amoxicillin and Clavulanate |
| Dyspnoea (shortness of breath) | 1,403 | 1.9 1.8–2.0ROR 2.0 · calibrated p 0.932 | 1.9 EB05 1.8 · IC025 +0.9 | Not in label — unassessed | serious PRR 1.8 | not reported in cached trials |
| Pyrexia (fever) | 1,397 | 3.1 3.0–3.3ROR 3.3 · calibrated p 0.549 | 3.1 EB05 3.0 · IC025 +1.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.7 | not reported in cached trials |
| Fatigue (tiredness) | 1,280 | 1.3 1.2–1.3ROR 1.3 · calibrated p 0.503 | 1.3 EB05 1.2 · IC025 +0.3 | Not in label — unassessed | serious PRR 1.4 | not reported in cached trials |
| Pneumonia (lung infection) | 1,192 | 2.9 2.7–3.0ROR 3.0 · calibrated p 0.641 | 2.9 EB05 2.7 · IC025 +1.4 3/3 methods agree | Likely indication confounding term in indications | serious PRR 2.2 | not reported in cached trials |
| Vomiting | 1,184 | 2.0 1.9–2.1ROR 2.0 · calibrated p 0.948 | 2.0 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 1.7 | NCT05584657: 4/1,107 (0.4%) on Amoxicillin and Clavulanate |
| Rash | 1,033 | 1.9 1.7–2.0ROR 1.9 · calibrated p 0.880 | 1.8 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 2.3 | not reported in cached trials |
| Pain | 983 | 1.2 1.2–1.3ROR 1.2 · calibrated p 0.474 | 1.2 EB05 1.2 · IC025 +0.2 | Not in label — unassessed | serious PRR 1.2 | NCT05584657: 1/1,107 (0.1%) on Amoxicillin and Clavulanate (serious AE) |
| Headache | 935 | 1.2 1.1–1.2ROR 1.2 · calibrated p 0.417 | 1.2 EB05 1.1 · IC025 +0.1 | Labeled adverse reaction exact term | serious PRR 1.3 | NCT05584657: 17/1,107 (1.5%) on Amoxicillin and Clavulanate |
| Drug ineffective (drug did not work) | 859 | 0.5 0.5–0.5ROR 0.5 · calibrated p 0.045 ✓ | 0.5 EB05 0.5 · IC025 -1.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.7 | not reported in cached trials |
| Pruritus (itching) | 859 | 1.8 1.7–1.9ROR 1.8 · calibrated p 0.825 | 1.8 EB05 1.7 · IC025 +0.7 | Labeled adverse reaction exact term | serious PRR 2.6 | not reported in cached trials |
| Acute kidney injury (sudden kidney damage) | 853 | 4.4 4.1–4.7ROR 4.5 · calibrated p 0.300 | 4.3 EB05 4.1 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 | not reported in cached trials |
| Sinusitis | 843 | 6.4 6.0–6.9ROR 6.6 · calibrated p 0.117 | 6.3 EB05 6.0 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | 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.
- Pulmonary vasculitis — n=32, PRR 49.9
- Total lung capacity abnormal — n=22, PRR 47.5
- Mixed liver injury — n=148, PRR 41.5
- Sputum purulent — n=26, PRR 31.7
- Vascular purpura — n=53, PRR 30.7
- Chronic kidney disease-mineral and bone disorder — n=33, PRR 24.5
- Normochromic normocytic anaemia — n=88, PRR 23.4
- Choroidal effusion — n=22, PRR 21.9
- Neuritis — n=39, PRR 20.2
- Hepatocellular injury — n=358, PRR 20.0
✓ 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 and Clavulanate?
In FDA FAERS, the most frequently co-reported reaction terms for Amoxicillin and Clavulanate are diarrhoea, drug hypersensitivity, nausea, dyspnoea, pyrexia, fatigue. 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 and Clavulanate have an FDA boxed warning?
No. The FDA label retrieved for Amoxicillin and Clavulanate has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Amoxicillin and Clavulanate 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, 1,222 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 2026-10-14. 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.