Reported Reactions

Drugs › Penicillin-class antibacterial

Generic name

Oxacillin: adverse event reports filed with FDA

557 reports list it as a suspect or interacting product, 2004–2026. Class: Penicillin-class antibacterial.

557
reports as suspect product
0% of all reports · about 25 a year
22
reports, 12 months to June 2026
33 in the 12 months before
94.3%
marked serious by the reporter
81% across the class
14%
record death among outcomes, as reported
78 reports · not verified by FDA

557 adverse event reports received by FDA list oxacillin, a generic name as a suspect or interacting product, from February 2004 to June 2026. A further 402 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 22 reports listed it, down 33% from 33 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 25 reports a year and 0% of the 20,646,523 reports in the database, and 0.9% of the reports for the penicillin-class antibacterial class. How many people take it is not in the data, so a count is not a rate of occurrence.

The MedDRA terms listed most often are drug ineffective (9.9%), drug reaction with eosinophilia and systemic symptoms (9.2%) and acute kidney injury (6.8%). A report can list several reactions, so shares add to more than 100%; 237 different terms appear across these reports. Drug ineffective is recorded in 9.9% of these reports, a larger share than in the median penicillin-class antibacterial drug (5%).

94.3% of the reports are marked serious by the reporter (81% across the class); 14% record death among the outcomes and 49.7% record hospitalisation, as reported. 61.4% of the reports came from other health professionals, and the largest patient age group is 45 to 64 (23.3%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

047Jul 2021: 1Aug 2021: 2Sep 2021: 1Oct 2021: 1Nov 2021: 0Dec 2021: 12022Jan 2022: 7Feb 2022: 4Mar 2022: 1Apr 2022: 1May 2022: 6Jun 2022: 2Jul 2022: 4Aug 2022: 0Sep 2022: 0Oct 2022: 0Nov 2022: 1Dec 2022: 02023Jan 2023: 6Feb 2023: 7Mar 2023: 1Apr 2023: 1May 2023: 2Jun 2023: 1Jul 2023: 0Aug 2023: 1Sep 2023: 4Oct 2023: 7Nov 2023: 1Dec 2023: 22024Jan 2024: 1Feb 2024: 6Mar 2024: 6Apr 2024: 2May 2024: 1Jun 2024: 2Jul 2024: 2Aug 2024: 0Sep 2024: 1Oct 2024: 3Nov 2024: 0Dec 2024: 52025Jan 2025: 5Feb 2025: 2Mar 2025: 4Apr 2025: 7May 2025: 3Jun 2025: 1Jul 2025: 4Aug 2025: 2Sep 2025: 0Oct 2025: 2Nov 2025: 0Dec 2025: 12026Jan 2026: 5Feb 2026: 1Mar 2026: 3Apr 2026: 3May 2026: 0Jun 2026: 1

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

026522004: 2820042005: 152006: 72007: 1520072008: 82009: 152010: 420102011: 202012: 242013: 720132014: 372015: 302016: 2020162017: 262018: 502019: 3620192020: 522021: 312022: 2620222023: 332024: 292025: 3120252026: 13

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Oxacillin reports recording the termmedian drug in penicillin-class antibacterial

  1. Drug ineffectivethe medicine did not work as expected9.9%55
  2. Drug reaction with eosinophilia and systemic symptomsDRESS, a severe reaction with rash, fever and organ involvement9.2%51
  3. Acute kidney injurysudden loss of kidney function6.8%38
  4. Rashskin rash5.2%29
  5. Pyrexiafever3.4%19
  6. Toxic epidermal necrolysisa severe skin reaction with peeling3.4%19
  7. Infectionan infection, type not specified3.1%17
  8. Alanine aminotransferase increasedraised liver enzyme (ALT)2.9%16
  9. Off label useused for a purpose or in a way not on the label2.7%15
  10. Aspartate aminotransferase increasedraised liver enzyme (AST)2.5%14
  11. Condition aggravatedthe condition being treated got worse2.3%13
  12. Neutropenialow neutrophils, a type of white blood cell2.2%12
  13. Thrombocytopenialow platelets2.2%12
  14. Pneumonialung infection2%11
  15. Product use in unapproved indicationused for a purpose not on the label2%11
  16. Toxicity to various agentspoisoning or toxic effect of one or more substances2%11
  17. Treatment failurethe treatment did not work2%11
  18. Eosinophilic myocarditis1.8%10
  19. Foetal exposure during pregnancythe unborn baby was exposed to the medicine1.6%9
  20. Premature babya baby born early1.6%9
  21. Septic shockshock arising from infection1.6%9
  22. Cutaneous vasculitis1.4%8
  23. Device related infectionan infection related to the device1.4%8

Top 30 of 237 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 15 drugs in the penicillin-class antibacterial class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death14%78
Life-threatening8.3%46
Hospitalisation (initial or prolonged)49.7%277
Disability1.3%7
Congenital anomaly0.2%1
Other serious57.6%321
Not serious5.7%32

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 64,409 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 22%11
2 to 118.1%45
12 to 173.1%17
18 to 4418.1%101
45 to 6423.3%130
65 to 746.3%35
75 and over8.6%48
Age not given30.5%170

Patient sex

Female32.7%182
Male45.6%254
Not given21.7%121

Who reported

Physician18.7%104
Pharmacist11.8%66
Other health professional61.4%342
Lawyer0%0
Consumer or non-health professional2.9%16
Not given5.2%29

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 42% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Staphylococcal infection559.9%
Staphylococcal bacteraemia498.8%
Antibiotic therapy264.7%
Staphylococcal sepsis254.5%
Infection213.8%
Endocarditis112%

The indication field is filled in by the reporter and is often blank; shares are of all 557 reports.

In context

MeasureOxacillinPenicillin-class antibacterialAll reports
Reports as suspect product55764,40920,646,523
Share of that pool—0.9%0%
Reports, latest 12 months22—1,332,454
Marked serious94.3%81%57.4%
Death recorded among outcomes, per 1,000 reports1408291
Hospitalisation recorded, per 1,000 reports497406213
Consumer-filed share2.9%18.4%45.8%
Top term, share of reportsDrug ineffective 9.9%median 5%6.3%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the penicillin-class antibacterial class

DrugName typeReportsLatest 12 monthsMarked serious
Amoxicillingeneric31,9842,31183.8%
Augmentinbrand9,43641272.2%
Piperacillin and tazobactamgeneric9,30758296.6%
Ampicillingeneric3,50520590%
Zosynbrand2,3595181%
Penicillin v potassiumgeneric1,2856336.3%
Penicillin ggeneric1,0457379%
Penicillin g sodiumgeneric1,0458025.6%
Bicillin L-Abrand89158111.6%
Unasynbrand7732290.9%
Ampicillin sodium, sulbactam sodiumgeneric5677792.9%
Ampicillin and sulbactamgeneric5622194.3%
Ampicillin sodiumgeneric558943.7%
Amoxilbrand535358.1%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Oxacillin reports

How many adverse event reports has FDA received for Oxacillin?

557 reports list Oxacillin as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 22 of them arrived in the latest 12 months. Another 402 list it only as a concomitant medication.

What reactions are recorded in Oxacillin reports?

drug ineffective (9.9%), drug reaction with eosinophilia and systemic symptoms (9.2%), acute kidney injury (6.8%), rash (5.2%) and pyrexia (3.4%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Oxacillin was responsible.

How serious are the reports?

94.3% are marked serious by the reporter. Among the outcomes recorded, 14% of reports include death and 49.7% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

other health professional (61.4%), physician (18.7%) and pharmacist (11.8%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Oxacillin rising?

22 reports in the 12 months to June 2026, down 33% from 33 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Oxacillin was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Oxacillin?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Oxacillin as a suspect or interacting product; reports listing it only as a concomitant medication (402) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.