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
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
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
- Drug ineffectivethe medicine did not work as expected9.9%55
- Drug reaction with eosinophilia and systemic symptomsDRESS, a severe reaction with rash, fever and organ involvement9.2%51
- Acute kidney injurysudden loss of kidney function6.8%38
- Rashskin rash5.2%29
- Pyrexiafever3.4%19
- Toxic epidermal necrolysisa severe skin reaction with peeling3.4%19
- Infectionan infection, type not specified3.1%17
- Alanine aminotransferase increasedraised liver enzyme (ALT)2.9%16
- Off label useused for a purpose or in a way not on the label2.7%15
- Aspartate aminotransferase increasedraised liver enzyme (AST)2.5%14
- Condition aggravatedthe condition being treated got worse2.3%13
- Drug resistance2.2%12
- Liver injury2.2%12
- Neutropenialow neutrophils, a type of white blood cell2.2%12
- Staphylococcal infection2.2%12
- Thrombocytopenialow platelets2.2%12
- Agranulocytosis2%11
- Pneumonialung infection2%11
- Product use in unapproved indicationused for a purpose not on the label2%11
- Toxicity to various agentspoisoning or toxic effect of one or more substances2%11
- Treatment failurethe treatment did not work2%11
- Bacteraemia1.8%10
- Eosinophilic myocarditis1.8%10
- Renal failure acute1.8%10
- Foetal exposure during pregnancythe unborn baby was exposed to the medicine1.6%9
- Premature babya baby born early1.6%9
- Septic shockshock arising from infection1.6%9
- Cutaneous vasculitis1.4%8
- 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
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
Patient sex
Who reported
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) | Reports | Share |
|---|---|---|
| Staphylococcal infection | 55 | 9.9% |
| Staphylococcal bacteraemia | 49 | 8.8% |
| Antibiotic therapy | 26 | 4.7% |
| Staphylococcal sepsis | 25 | 4.5% |
| Infection | 21 | 3.8% |
| Endocarditis | 11 | 2% |
The indication field is filled in by the reporter and is often blank; shares are of all 557 reports.
In context
| Measure | Oxacillin | Penicillin-class antibacterial | All reports |
|---|---|---|---|
| Reports as suspect product | 557 | 64,409 | 20,646,523 |
| Share of that pool | — | 0.9% | 0% |
| Reports, latest 12 months | 22 | — | 1,332,454 |
| Marked serious | 94.3% | 81% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 140 | 82 | 91 |
| Hospitalisation recorded, per 1,000 reports | 497 | 406 | 213 |
| Consumer-filed share | 2.9% | 18.4% | 45.8% |
| Top term, share of reports | Drug 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
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Amoxicillin | generic | 31,984 | 2,311 | 83.8% |
| Augmentin | brand | 9,436 | 412 | 72.2% |
| Piperacillin and tazobactam | generic | 9,307 | 582 | 96.6% |
| Ampicillin | generic | 3,505 | 205 | 90% |
| Zosyn | brand | 2,359 | 51 | 81% |
| Penicillin v potassium | generic | 1,285 | 63 | 36.3% |
| Penicillin g | generic | 1,045 | 73 | 79% |
| Penicillin g sodium | generic | 1,045 | 80 | 25.6% |
| Bicillin L-A | brand | 891 | 581 | 11.6% |
| Unasyn | brand | 773 | 22 | 90.9% |
| Ampicillin sodium, sulbactam sodium | generic | 567 | 77 | 92.9% |
| Ampicillin and sulbactam | generic | 562 | 21 | 94.3% |
| Ampicillin sodium | generic | 558 | 9 | 43.7% |
| Amoxil | brand | 535 | 3 | 58.1% |
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.