Cefprozil side effects: what 780 FDA adverse event reports show

Cefprozil · 39 reaction terms · 492 drug–reaction co-reports · data 2026-09-14

Drug class

Cephalosporin Antibacterial

FDA label (Established Pharmacologic Class)

Who reports

780 reports · 79% serious · 48 with death outcome · 64% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Cefprozil tablets are indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms in the conditions listed below: UPPER RESPIRATORY TRACT Pharyngitis/tonsillitis caused by Streptococcus pyogenes .

FDA label, Indications and Usage

What it is

DESCRIPTION Cefprozil, USP is a semi-synthetic broad-spectrum cephalosporin antibiotic. Cefprozil, USP is a cis and trans isomeric mixture (≥ 90% cis).

FDA label, Description section

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 31 strongest signals

Labeled adverse reaction 1Labeled (related wording) 1Likely indication confounding 2Reporting / coding artifact 3Lab value / disease marker 1Not in label — unassessed 23

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.
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. 8 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
Sputum discoloured	21	59.9 39.2–91.3ROR 61.5 · χ² 1,155 / p 2e-253	56.8 EB05 39.2 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 56.6 · ♀ 90% (drug 64%)	no trial data cached
Clostridium difficile colitis	17	43.1 26.9–69.0ROR 44.0 · χ² 657 / p 3e-145	41.2 EB05 27.2 · IC025 +3.5 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.8	no trial data cached
Secretion discharge	15	32.7 19.8–53.9ROR 33.3 · χ² 429 / p 1e-95	31.5 EB05 20.2 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 38.8	no trial data cached
Chronic kidney disease	89	31.2 25.7–38.0ROR 35.1 · χ² 2,582 / p <1e-300	31.0 EB05 26.0 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 23.0	no trial data cached
Choking	21	29.1 19.1–44.4ROR 29.9 · χ² 542 / p 4e-120	28.4 EB05 19.6 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 24.8 · ♀ 100% (drug 64%)	no trial data cached
End stage renal disease	19	27.8 17.8–43.3ROR 28.4 · χ² 464 / p 4e-103	27.1 EB05 18.3 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 20.1	no trial data cached
Ear infection	25	25.3 17.2–37.3ROR 26.1 · χ² 561 / p 3e-124	24.9 EB05 17.7 · IC025 +3.4 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 28.1	no trial data cached
Dry throat	9	23.8 12.5–45.7ROR 24.1 · χ² 175 / p 3e-40	22.4 EB05 11.9 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=9	no trial data cached
Ligament sprain	8	21.8 10.9–43.5ROR 22.0 · χ² 139 / p 3e-32	20.0 EB05 9.6 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious n=8	no trial data cached
Pharyngitis	9	19.4 10.1–37.2ROR 19.6 · χ² 139 / p 2e-32	17.9 EB05 8.9 · IC025 +2.2 3/3 methods agree	Likely indication confounding term in indications	serious PRR 16.2	no trial data cached
Tubulointerstitial nephritis	13	18.7 10.9–32.0ROR 19.0 · χ² 200 / p 1e-45	17.8 EB05 10.5 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 13.6	no trial data cached
Breast pain	7	17.7 8.4–36.9ROR 17.8 · χ² 94 / p 2e-22	15.1 EB05 6.1 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious n=7	no trial data cached
Diarrhoea haemorrhagic	6	17.2 7.8–38.2ROR 17.4 · χ² 76 / p 1e-18	13.8 EB05 5.1 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 13.4	no trial data cached
Renal tubular necrosis	6	16.4 7.4–36.4ROR 16.5 · χ² 72 / p 1e-17	12.9 EB05 4.8 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Colitis	22	15.7 10.4–23.7ROR 16.1 · χ² 289 / p 4e-65	15.3 EB05 10.3 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.2 · ♀ 14% (drug 64%) · 73% consumer	no trial data cached
Sneezing	13	15.6 9.1–26.8ROR 15.9 · χ² 164 / p 8e-38	14.6 EB05 8.2 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 28.3	no trial data cached
Wheezing	33	15.0 10.7–21.0ROR 15.6 · χ² 418 / p 3e-93	14.7 EB05 10.8 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 14.5 · ♀ 97% (drug 64%)	no trial data cached
Obstructive airways disorder	6	14.5 6.5–32.1ROR 14.6 · χ² 62 / p 1e-15	10.9 EB05 4.2 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 10.9	no trial data cached
Splenomegaly	6	13.8 6.2–30.6ROR 13.9 · χ² 59 / p 8e-15	10.2 EB05 4.0 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious PRR 11.2	no trial data cached
Product availability issue	11	13.2 7.3–23.7ROR 13.4 · χ² 112 / p 2e-26	11.5 EB05 6.0 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 19.8	no trial data cached
Product administration error	9	12.1 6.3–23.2ROR 12.3 · χ² 81 / p 1e-19	9.8 EB05 4.8 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 21.5	no trial data cached
Sinus congestion	6	11.9 5.4–26.5ROR 12.0 · χ² 50 / p 9e-13	8.4 EB05 3.5 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious n=5	no trial data cached
Blood lactate dehydrogenase increased	7	11.8 5.6–24.7ROR 11.9 · χ² 59 / p 8e-15	8.8 EB05 3.9 · IC025 +1.5 3/3 methods agree	Lab value / disease marker	serious PRR 9.1	no trial data cached
Oropharyngeal pain (sore throat)	39	11.3 8.3–15.4ROR 11.9 · χ² 358 / p 3e-80	10.9 EB05 8.1 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 15.6	no trial data cached
Injection site extravasation	5	10.8 4.5–25.8ROR 10.8 · χ² 35 / p 2e-9	6.9 EB05 2.8 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious n=5	no trial data cached
Renal injury	12	10.7 6.1–18.8ROR 10.9 · χ² 97 / p 4e-23	9.0 EB05 5.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 7.8	no trial data cached
Rotator cuff syndrome	5	10.4 4.4–25.0ROR 10.5 · χ² 34 / p 3e-9	6.6 EB05 2.8 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 8.8	no trial data cached
Lymphoma	6	10.4 4.7–23.1ROR 10.5 · χ² 42 / p 4e-11	7.1 EB05 3.2 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 7.6	no trial data cached
Aphonia	5	9.6 4.0–23.1ROR 9.7 · χ² 31 / p 2e-8	6.1 EB05 2.6 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 13.0	no trial data cached
Drug resistance	7	7.3 3.5–15.3ROR 7.4 · χ² 32 / p 7e-9	5.3 EB05 2.7 · IC025 +1.1 3/3 methods agree	Reporting / coding artifact	serious PRR 6.0	no trial data cached
Tardive dyskinesia (persistent involuntary movements)	6	5.7 2.6–12.6ROR 5.7 · χ² 19 / p 8e-6	4.1 EB05 2.1 · IC025 +0.6 3/3 methods agree	Not in label — unassessed	serious PRR 4.9	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	89	31.2 25.7–38.0ROR 35.1 · χ² 2,582 / p <1e-300	31.0 EB05 26.0 · IC025 +4.4 3/3 methods agree	Not in label — unassessed	serious PRR 23.0	no trial data cached
Oropharyngeal pain (sore throat)	39	11.3 8.3–15.4ROR 11.9 · χ² 358 / p 3e-80	10.9 EB05 8.1 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 15.6	no trial data cached
Wheezing	33	15.0 10.7–21.0ROR 15.6 · χ² 418 / p 3e-93	14.7 EB05 10.8 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 14.5 · ♀ 97% (drug 64%)	no trial data cached
Ear infection	25	25.3 17.2–37.3ROR 26.1 · χ² 561 / p 3e-124	24.9 EB05 17.7 · IC025 +3.4 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 28.1	no trial data cached
Colitis	22	15.7 10.4–23.7ROR 16.1 · χ² 289 / p 4e-65	15.3 EB05 10.3 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 12.2 · ♀ 14% (drug 64%) · 73% consumer	no trial data cached
Choking	21	29.1 19.1–44.4ROR 29.9 · χ² 542 / p 4e-120	28.4 EB05 19.6 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious PRR 24.8 · ♀ 100% (drug 64%)	no trial data cached
Sputum discoloured	21	59.9 39.2–91.3ROR 61.5 · χ² 1,155 / p 2e-253	56.8 EB05 39.2 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 56.6 · ♀ 90% (drug 64%)	no trial data cached
End stage renal disease	19	27.8 17.8–43.3ROR 28.4 · χ² 464 / p 4e-103	27.1 EB05 18.3 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 20.1	no trial data cached
Clostridium difficile colitis	17	43.1 26.9–69.0ROR 44.0 · χ² 657 / p 3e-145	41.2 EB05 27.2 · IC025 +3.5 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.8	no trial data cached
Secretion discharge	15	32.7 19.8–53.9ROR 33.3 · χ² 429 / p 1e-95	31.5 EB05 20.2 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 38.8	no trial data cached
Sneezing	13	15.6 9.1–26.8ROR 15.9 · χ² 164 / p 8e-38	14.6 EB05 8.2 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 28.3	no trial data cached
Tubulointerstitial nephritis	13	18.7 10.9–32.0ROR 19.0 · χ² 200 / p 1e-45	17.8 EB05 10.5 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 13.6	no trial data cached
Renal injury	12	10.7 6.1–18.8ROR 10.9 · χ² 97 / p 4e-23	9.0 EB05 5.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 7.8	no trial data cached
Product availability issue	11	13.2 7.3–23.7ROR 13.4 · χ² 112 / p 2e-26	11.5 EB05 6.0 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 19.8	no trial data cached
Product administration error	9	12.1 6.3–23.2ROR 12.3 · χ² 81 / p 1e-19	9.8 EB05 4.8 · IC025 +1.8 3/3 methods agree	Reporting / coding artifact	serious PRR 21.5	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.

Sputum discoloured — n=21, PRR 59.9
Chronic kidney disease — n=89, PRR 31.2
Choking — n=21, PRR 29.1
Wheezing — n=33, PRR 15.0
Oropharyngeal pain — n=39, PRR 11.3

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 Cefprozil?

In FDA FAERS, the most frequently co-reported reaction terms for Cefprozil are chronic kidney disease, oropharyngeal pain, wheezing, ear infection, colitis, choking. 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 Cefprozil have an FDA boxed warning?

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

Do FAERS signals prove that Cefprozil 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 3391de8b-7bc9-4624-a5c4-836135b39d99, effective 20180831; matched on openfda.generic_name.exact:"CEFPROZIL")
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, 39 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.