Reported Reactions

Drugs › Penicillin-class antibacterial

Generic name

Penicillin g: adverse event reports filed with FDA

1,045 reports list it as a suspect or interacting product, 2004–2026. Class: Penicillin-class antibacterial. Also reported as Penicillin G /00000901/, Penicillin G /00000903/.

1,045
reports as suspect product
0% of all reports · about 47 a year
73
reports, 12 months to June 2026
118 in the 12 months before
79%
marked serious by the reporter
81% across the class
9.4%
record death among outcomes, as reported
98 reports · not verified by FDA

1,045 adverse event reports received by FDA list penicillin g, a generic name as a suspect or interacting product, from February 2004 to June 2026. A further 784 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, 73 reports listed it, down 38% from 118 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 47 reports a year and 0% of the 20,646,523 reports in the database, and 1.6% 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 reactions recorded most often are drug hypersensitivity (36.3%), drug ineffective (17.5%) and dyspnoea (16.5%). A report can list several reactions, so shares add to more than 100%; 431 different terms appear across these reports. Drug hypersensitivity is recorded in 36.3% of these reports, a larger share than in the median penicillin-class antibacterial drug (9%).

79% of the reports are marked serious by the reporter (81% across the class); 9.4% record death among the outcomes and 30.7% record hospitalisation, as reported. 45.6% of the reports came from other health professionals, and the largest patient age group is 45 to 64 (27.8%). 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

01223Jul 2021: 12Aug 2021: 10Sep 2021: 6Oct 2021: 6Nov 2021: 6Dec 2021: 72022Jan 2022: 8Feb 2022: 5Mar 2022: 8Apr 2022: 6May 2022: 6Jun 2022: 13Jul 2022: 8Aug 2022: 17Sep 2022: 6Oct 2022: 11Nov 2022: 15Dec 2022: 112023Jan 2023: 20Feb 2023: 10Mar 2023: 5Apr 2023: 14May 2023: 12Jun 2023: 8Jul 2023: 8Aug 2023: 18Sep 2023: 17Oct 2023: 18Nov 2023: 14Dec 2023: 92024Jan 2024: 10Feb 2024: 18Mar 2024: 23Apr 2024: 6May 2024: 7Jun 2024: 16Jul 2024: 12Aug 2024: 6Sep 2024: 17Oct 2024: 17Nov 2024: 11Dec 2024: 132025Jan 2025: 9Feb 2025: 9Mar 2025: 11Apr 2025: 5May 2025: 2Jun 2025: 6Jul 2025: 8Aug 2025: 6Sep 2025: 15Oct 2025: 7Nov 2025: 5Dec 2025: 82026Jan 2026: 4Feb 2026: 3Mar 2026: 2Apr 2026: 5May 2026: 3Jun 2026: 7

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

0781562004: 920042005: 62006: 102007: 1220072008: 72009: 202010: 820102011: 72012: 122013: 720132014: 102015: 192016: 1620162017: 322018: 562019: 8120192020: 912021: 1042022: 11420222023: 1532024: 1562025: 9120252026: 24

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

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

  1. Drug hypersensitivityan allergic-type reaction to a medicine36.3%379
  2. Drug ineffectivethe medicine did not work as expected17.5%183
  3. Dyspnoeashortness of breath16.5%172
  4. Rashskin rash16.4%171
  5. Drug intolerancethe medicine was not tolerated16.1%168
  6. Diarrhoealoose or frequent stools15.4%161
  7. Malaisegeneral feeling of being unwell14.5%152
  8. Abdominal pain upperupper stomach pain13.7%143
  9. Coughcough11%115
  10. Nauseafeeling sick11%115
  11. Hypertensionhigh blood pressure9.7%101
  12. Anxietyanxiety9.5%99
  13. Pruritusitching9.2%96
  14. Condition aggravatedthe condition being treated got worse8.8%92
  15. Hypersensitivityan allergic-type reaction8.1%85
  16. Arthralgiajoint pain7.9%83
  17. Off label useused for a purpose or in a way not on the label7.9%83
  18. Vomitingbeing sick7.9%83
  19. Headachehead pain7.8%81
  20. Hepatic steatosisfatty liver7.8%81
  21. Abdominal discomfortstomach discomfort7.6%79
  22. Urticariahives7.6%79
  23. Fatiguetiredness7.3%76
  24. Pneumonialung infection7.3%76
  25. Abdominal painstomach or belly pain7.2%75
  26. Cardiac failure congestivecongestive heart failure7%73
  27. Anaphylactic reactiona severe, sudden allergic reaction6.9%72
  28. Asthmaasthma6.7%70

Top 30 of 431 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

Death9.4%98
Life-threatening11.1%116
Hospitalisation (initial or prolonged)30.7%321
Disability4.8%50
Congenital anomaly1%10
Other serious65.6%685
Not serious21%219

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 20.7%7
2 to 113.2%33
12 to 171.2%13
18 to 4413.1%137
45 to 6427.8%290
65 to 7412.2%127
75 and over4.4%46
Age not given37.5%392

Patient sex

Female55.4%579
Male34.3%358
Not given10.3%108

Who reported

Physician24%251
Pharmacist2.4%25
Other health professional45.6%476
Lawyer0.1%1
Consumer or non-health professional26.1%273
Not given1.8%19

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 30.9% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Antibiotic therapy181.7%
Erysipelas101%
Skin test80.8%
Cellulitis60.6%
Endocarditis bacterial60.6%
Hidradenitis50.5%

The indication field is filled in by the reporter and is often blank; shares are of all 1,045 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Penicillin g reports
Prednisone20619.7%
Codeine17616.8%
Ciprofloxacin17216.5%
Cephalexin14413.8%
Clindamycin12912.3%
Celebrex11310.8%
Methotrexate10810.3%
Moxifloxacin10510%
Clarithromycin989.4%
Albuterol938.9%

Other products listed in reports where Penicillin g is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasurePenicillin gPenicillin-class antibacterialAll reports
Reports as suspect product1,04564,40920,646,523
Share of that pool—1.6%0%
Reports, latest 12 months73—1,332,454
Marked serious79%81%57.4%
Death recorded among outcomes, per 1,000 reports948291
Hospitalisation recorded, per 1,000 reports307406213
Consumer-filed share26.1%18.4%45.8%
Top term, share of reportsDrug hypersensitivity 36.3%median 9%0.9%

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 g sodiumgeneric1,0458025.6%
Bicillin L-Abrand89158111.6%
Unasynbrand7732290.9%
Ampicillin sodium, sulbactam sodiumgeneric5677792.9%
Ampicillin and sulbactamgeneric5622194.3%
Ampicillin sodiumgeneric558943.7%
Oxacillingeneric5572294.3%
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 Penicillin g reports

How many adverse event reports has FDA received for Penicillin g?

1,045 reports list Penicillin g as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 73 of them arrived in the latest 12 months. Another 784 list it only as a concomitant medication.

What reactions are recorded in Penicillin g reports?

drug hypersensitivity (36.3%), drug ineffective (17.5%), dyspnoea (16.5%), rash (16.4%) and drug intolerance (16.1%). 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 Penicillin g was responsible.

How serious are the reports?

79% are marked serious by the reporter. Among the outcomes recorded, 9.4% of reports include death and 30.7% 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 (45.6%), consumer or non-health professional (26.1%) and physician (24%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Penicillin g rising?

73 reports in the 12 months to June 2026, down 38% from 118 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 Penicillin g 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 Penicillin g?

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 Penicillin g as a suspect or interacting product; reports listing it only as a concomitant medication (784) 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.