Prescription medicine
Penicillin g Brand names: Pfizerpen
Penicillin g (Pfizerpen) is a prescription medicine with an FDA approval on record since 1990. FDA's NDC Directory lists it from 8 generic labelers.
- Generic listed
Check it at the source: the penicillin g FDA label on DailyMed (effective September 16, 2020, Sandoz Inc); the NDA 50638 record on Drugs@FDA; every penicillin g label on DailyMed.
Highlights of the record
FDA label of September 16, 2020; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
Used for
From the label: indications and usageTherapy Buffered penicillin G potassium for injection is indicated in the treatment of serious infections caused by susceptible strains of the designated microorganisms in the conditions listed below.
Forms and strengths
- 50ml
Injection (powder) for solution; powder for solution; injection (solution).
On the market
- Earliest approval on file
- June 25, 1990 Penicillin G Potassium In Plastic Container, Baxter Hlthcare; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 14 first February 6, 1947; 6 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 9 of which 8 under generic applications, 1 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- 1 since 2025 1 Class I among all firms' recalls; latest June 27, 2025
- FAERS reports
- 3,439 through July 30, 2026
What is penicillin g used for?
From the label: indications and usageTherapy Buffered penicillin G potassium for injection is indicated in the treatment of serious infections caused by susceptible strains of the designated microorganisms in the conditions listed below. Appropriate culture and susceptibility tests should be done before treatment in order to isolate and identify organisms causing infection and to determine their susceptibility to penicillin G. Therapy with Buffered penicillin G potassium for injection may be initiated before results of such tests are known when there is reason to believe the infection may involve any of the organisms listed below, however, once these results become available, appropriate therapy should be continued. […]
Conditions named in the indications of penicillin g's FDA labels, with every medicine labeled for each:
From other penicillin g labelsBacterial infections: INDICATIONS AND USAGE Therapy Buffered penicillin G potassium for injection is indicated in the treatment of serious infections caused by susceptible strains of the designated microorganisms in the conditions listed below.
FDA pharmacologic class: Penicillin-class Antibacterial.
Source: FDA drug label (Penicillin G Potassium), Sandoz Inc, effective September 16, 2020 (SPL set 91950983-4884-40d1-abd8-bcc953d61b7f), via openFDA; the full label on DailyMed
Is there a generic for penicillin g (Pfizerpen)?
The FDA approved the first generic penicillin g on February 6, 1947. 14 generic applications are approved; 6 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists penicillin g from 8 labelers under a generic (ANDA) application and from 1 brand labeler. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
- 1990 earliest approval on file
- 1947 first generic approved
- red ticks recalls
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
Has penicillin g been recalled?
The FDA's Enforcement Report lists 1 recall naming penicillin g since 2025: 1 Class I (the most serious), 0 Class II, 0 Class III; 1 still ongoing. A recall names products and lots, not every product of the medicine.
| Started | Class | Company | Reason |
|---|---|---|---|
| June 27, 2025 | Class I | Sandoz Inc | Labeling: Label Mix-Up; Some vials of Cefazolin for Injection, USP 1 gram were incorrectly labeled as penicillin G potassium for Injection, USP, 20 million Unit |
Source: FDA Enforcement Report (drug recalls) via openFDA, through October 8, 2026
What does the penicillin g label say about other medicines?
The penicillin g label names 7 other medicines in its interaction, contraindication or warning sections. The labels of 8 other medicines name penicillin g. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Aspirin | drug interactions | These drugs include: aspirin, phenylbutazone, sulfonamides, indomethacin, thiazide diuretics, furosemide and ethacrynic acid. |
| Chloramphenicol | drug interactions | Drug Interactions Bacteriostatic antibacterials (i.e., chloramphenicol, erythromycins, sulfonamides or tetracyclines) may antagonize the bactericidal effect of penicillin, and concurrent use of these drugs should be avoided. |
| Epinephrine | warnings | SERIOUS ANAPHYLACTIC REACTIONS REQUIRE IMMEDIATE EMERGENCY TREATMENT WITH EPINEPHRINE. |
| Ethacrynic acid | drug interactions | These drugs include: aspirin, phenylbutazone, sulfonamides, indomethacin, thiazide diuretics, furosemide and ethacrynic acid. |
| Furosemide | drug interactions | These drugs include: aspirin, phenylbutazone, sulfonamides, indomethacin, thiazide diuretics, furosemide and ethacrynic acid. |
| Indomethacin | drug interactions | These drugs include: aspirin, phenylbutazone, sulfonamides, indomethacin, thiazide diuretics, furosemide and ethacrynic acid. |
| Probenecid | drug interactions | Penicillin blood levels may be prolonged by concurrent administration of probenecid which blocks the renal tubular secretion of penicillins. |
Other labels that name penicillin g
Source: FDA drug label (Penicillin G Potassium), Sandoz Inc, effective September 16, 2020 (SPL set 91950983-4884-40d1-abd8-bcc953d61b7f), via openFDA; the full label on DailyMed
What do FAERS reports show for penicillin g?
The FDA Adverse Event Reporting System holds 3,439 reports that list penicillin g among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 271 are coded as a death and 917 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
How does penicillin g compare with medicines for the same use?
1 side-by-side page set penicillin g beside a medicine whose label shares a use: approvals, generics, pharmacy cost, warnings and supply.
What next?
- Other penicillins
- the pharmacologic class, with prices and generics
- Penicillin g side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other