Oxacillin Sodium side effects: what 1,116 FDA adverse event reports show

Oxacillin Sodium · 43 reaction terms · 668 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Who reports

1,116 reports · 92% serious · 214 with death outcome · 38% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Oxacillin is indicated in the treatment of infections caused by penicillinase producing staphylococci which have demonstrated susceptibility to the drug. Cultures and susceptibility tests should be performed initially to determine the causative organism and its susceptibility to the drug (see CLINICAL PHARMACOLOGY-Susceptibility Testing ).

FDA label, Indications and Usage

What it is

DESCRIPTION: Oxacillin for Injection, USP is a semisynthetic penicillin antibiotic derived from the penicillin nucleus, 6-amino-penicillanic acid. It is resistant to inactivation by the enzyme penicillinase (beta-lactamase). It is the sodium salt in parenteral dosage form for intramuscular or intravenous use.

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 2Labeled (related wording) 1Likely indication confounding 2Reporting / coding artifact 4Not in label — unassessed 22

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.
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. 12 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
Toxic epidermal necrolysis (severe skin peeling reaction)	42	52.5 39.0–70.6ROR 54.5 · χ² 2,065 / p <1e-300	51.2 EB05 39.5 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious PRR 32.6 · 100% clinician	no trial data cached
Drug reaction with eosinophilia and systemic symptoms	68	50.1 39.8–63.1ROR 53.3 · χ² 3,221 / p <1e-300	49.4 EB05 40.3 · IC025 +4.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.1 · 100% clinician	no trial data cached
Renal tubular necrosis	17	32.5 20.3–52.2ROR 33.0 · χ² 488 / p 2e-108	31.5 EB05 20.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 20.4	no trial data cached
Eosinophilia	29	31.2 21.8–44.7ROR 32.0 · χ² 818 / p 3e-180	30.6 EB05 22.4 · IC025 +3.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 19.6 · 96% clinician	no trial data cached
Toxic skin eruption	16	29.8 18.3–48.5ROR 30.2 · χ² 416 / p 7e-93	28.8 EB05 18.8 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 18.6	no trial data cached
Bacteraemia	17	27.2 16.9–43.6ROR 27.6 · χ² 402 / p 8e-90	26.4 EB05 17.4 · IC025 +3.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 17.0	no trial data cached
Device related infection	20	24.4 15.8–37.7ROR 24.8 · χ² 425 / p 9e-95	23.8 EB05 16.3 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 15.6	no trial data cached
Hepatic cytolysis	15	23.1 14.0–38.2ROR 23.4 · χ² 295 / p 2e-66	22.4 EB05 14.3 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 14.4	no trial data cached
Staphylococcal infection	39	22.2 16.3–30.2ROR 22.9 · χ² 767 / p 4e-169	21.9 EB05 16.7 · IC025 +3.6 3/3 methods agree	Likely indication confounding term in indications	serious PRR 14.8 · 100% clinician	no trial data cached
Drug resistance	28	20.5 14.2–29.6ROR 21.0 · χ² 500 / p 4e-111	20.2 EB05 14.6 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 13.8 · 100% clinician	no trial data cached
Multi-organ failure	18	19.3 12.2–30.5ROR 19.6 · χ² 294 / p 3e-66	18.8 EB05 12.3 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Disseminated intravascular coagulation	14	18.6 11.1–31.4ROR 18.9 · χ² 216 / p 3e-49	17.9 EB05 10.8 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 11.6	no trial data cached
Cardiogenic shock	14	18.4 11.0–31.1ROR 18.7 · χ² 214 / p 1e-48	17.7 EB05 10.7 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 11.5	no trial data cached
Vasculitis	10	16.1 8.7–29.9ROR 16.3 · χ² 127 / p 9e-30	14.6 EB05 7.3 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 10.8	no trial data cached
Hypomagnesaemia	10	13.6 7.3–25.1ROR 13.7 · χ² 104 / p 1e-24	11.7 EB05 5.8 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.7	no trial data cached
Agranulocytosis (severe loss of white cells)	13	13.2 7.7–22.7ROR 13.4 · χ² 135 / p 2e-31	11.9 EB05 6.6 · IC025 +2.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.2	no trial data cached
Renal failure acute	29	12.7 8.8–18.1ROR 13.0 · χ² 300 / p 1e-67	12.2 EB05 8.6 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 8.0 · 96% clinician	no trial data cached
Drug level increased	11	12.5 6.9–22.5ROR 12.6 · χ² 105 / p 6e-25	10.7 EB05 5.6 · IC025 +2.0 3/3 methods agree	Reporting / coding artifact	serious PRR 8.6	no trial data cached
Liver injury	16	12.4 7.6–20.2ROR 12.6 · χ² 157 / p 2e-36	11.3 EB05 6.8 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 7.0	no trial data cached
Rash maculo-papular	14	11.9 7.1–20.0ROR 12.0 · χ² 129 / p 4e-30	10.5 EB05 6.1 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 8.2	no trial data cached
Septic shock	26	11.3 7.7–16.5ROR 11.6 · χ² 234 / p 3e-53	10.6 EB05 7.3 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 7.0 · ♀ 13% (drug 38%)	no trial data cached
Face oedema	10	11.1 6.0–20.6ROR 11.2 · χ² 82 / p 7e-20	9.0 EB05 4.7 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 7.7	no trial data cached
Tubulointerstitial nephritis	11	11.0 6.1–19.9ROR 11.1 · χ² 91 / p 8e-22	9.1 EB05 4.9 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.3	no trial data cached
Cholestasis (bile flow blockage)	11	10.8 6.0–19.5ROR 10.9 · χ² 89 / p 2e-21	8.9 EB05 4.8 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 6.8	no trial data cached
Drug-induced liver injury	15	9.1 5.5–15.1ROR 9.3 · χ² 101 / p 5e-24	7.8 EB05 4.8 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.7	no trial data cached
Lactic acidosis	15	8.8 5.3–14.5ROR 8.9 · χ² 96 / p 6e-23	7.4 EB05 4.6 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 5.5	no trial data cached
Transaminases increased	10	8.5 4.6–15.7ROR 8.5 · χ² 59 / p 1e-14	6.6 EB05 3.7 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 5.6	no trial data cached
Premature baby	13	8.1 4.7–13.9ROR 8.2 · χ² 74 / p 4e-18	6.7 EB05 4.0 · IC025 +1.7 3/3 methods agree	Not in label — unassessed	serious PRR 5.1	no trial data cached
Jaundice (yellowing of skin/eyes)	11	7.7 4.3–13.8ROR 7.7 · χ² 57 / p 2e-14	6.1 EB05 3.6 · IC025 +1.5 3/3 methods agree	Not in label — unassessed	serious PRR 5.0	no trial data cached
Rhabdomyolysis (muscle breakdown)	16	7.2 4.4–11.8ROR 7.3 · χ² 80 / p 2e-19	6.2 EB05 4.0 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.5	no trial data cached
Foetal exposure during pregnancy	13	3.0 1.8–5.2ROR 3.0 · χ² 16 / p 4e-5	2.8 EB05 1.8 · IC025 +0.5	Reporting / coding artifact	serious PRR 1.9	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
Drug reaction with eosinophilia and systemic symptoms	68	50.1 39.8–63.1ROR 53.3 · χ² 3,221 / p <1e-300	49.4 EB05 40.3 · IC025 +4.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 31.1 · 100% clinician	no trial data cached
Toxic epidermal necrolysis (severe skin peeling reaction)	42	52.5 39.0–70.6ROR 54.5 · χ² 2,065 / p <1e-300	51.2 EB05 39.5 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious PRR 32.6 · 100% clinician	no trial data cached
Staphylococcal infection	39	22.2 16.3–30.2ROR 22.9 · χ² 767 / p 4e-169	21.9 EB05 16.7 · IC025 +3.6 3/3 methods agree	Likely indication confounding term in indications	serious PRR 14.8 · 100% clinician	no trial data cached
Renal failure acute	29	12.7 8.8–18.1ROR 13.0 · χ² 300 / p 1e-67	12.2 EB05 8.6 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 8.0 · 96% clinician	no trial data cached
Eosinophilia	29	31.2 21.8–44.7ROR 32.0 · χ² 818 / p 3e-180	30.6 EB05 22.4 · IC025 +3.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 19.6 · 96% clinician	no trial data cached
Drug resistance	28	20.5 14.2–29.6ROR 21.0 · χ² 500 / p 4e-111	20.2 EB05 14.6 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 13.8 · 100% clinician	no trial data cached
Septic shock	26	11.3 7.7–16.5ROR 11.6 · χ² 234 / p 3e-53	10.6 EB05 7.3 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 7.0 · ♀ 13% (drug 38%)	no trial data cached
Device related infection	20	24.4 15.8–37.7ROR 24.8 · χ² 425 / p 9e-95	23.8 EB05 16.3 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 15.6	no trial data cached
Multi-organ failure	18	19.3 12.2–30.5ROR 19.6 · χ² 294 / p 3e-66	18.8 EB05 12.3 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Bacteraemia	17	27.2 16.9–43.6ROR 27.6 · χ² 402 / p 8e-90	26.4 EB05 17.4 · IC025 +3.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 17.0	no trial data cached
Renal tubular necrosis	17	32.5 20.3–52.2ROR 33.0 · χ² 488 / p 2e-108	31.5 EB05 20.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 20.4	no trial data cached
Rhabdomyolysis (muscle breakdown)	16	7.2 4.4–11.8ROR 7.3 · χ² 80 / p 2e-19	6.2 EB05 4.0 · IC025 +1.8 3/3 methods agree	Not in label — unassessed	serious PRR 4.5	no trial data cached
Liver injury	16	12.4 7.6–20.2ROR 12.6 · χ² 157 / p 2e-36	11.3 EB05 6.8 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 7.0	no trial data cached
Toxic skin eruption	16	29.8 18.3–48.5ROR 30.2 · χ² 416 / p 7e-93	28.8 EB05 18.8 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 18.6	no trial data cached
Lactic acidosis	15	8.8 5.3–14.5ROR 8.9 · χ² 96 / p 6e-23	7.4 EB05 4.6 · IC025 +1.9 3/3 methods agree	Not in label — unassessed	serious PRR 5.5	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.

Toxic epidermal necrolysis — n=42, PRR 52.5
Renal failure acute — n=29, PRR 12.7
Septic shock — n=26, 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 Oxacillin?

In FDA FAERS, the most frequently co-reported reaction terms for Oxacillin are drug reaction with eosinophilia and systemic symptoms, toxic epidermal necrolysis, staphylococcal infection, renal failure acute, eosinophilia, septic shock. 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 Oxacillin have an FDA boxed warning?

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

Do FAERS signals prove that Oxacillin 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 af2dccac-98c8-488f-a133-6374b3ca8dba, effective 20200729; matched on openfda.generic_name.exact:"OXACILLIN")
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.