Two medicines, side by side
Ampicillin vs vancomycin
Ampicillin and vancomycin are both labeled for bacterial infections. Drugs@FDA records approvals of ampicillin since 1966 and of vancomycin since 1986. Pharmacies paid $0.441 per ampicillin 500 mg capsule and $1.33 per vancomycin HCl 125 mg capsule (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, ampicillin is a penicillin-class antibacterial and vancomycin a glycopeptide antibacterial.
Check it at the source: the ampicillin FDA label on DailyMed (effective February 21, 2025); the vancomycin FDA label on DailyMed (effective June 7, 2024).
Highlights of the ampicillin record
Ampicillin (Penbritin-S) · label of February 21, 2025
Used for
From the label: indicationsAmpicillin for injection is indicated in the treatment of infections caused by susceptible strains of the designated organisms in the following conditions: Respiratory Tract Infections caused by Streptococcus pneumoniae. Staphylococcus aureus (penicillinase and nonpenicillinase-producing), H. influenzae, and Group A beta-hemolytic streptococci. […]
On the market
- Earliest approval on file
- December 29, 1966
- Generic labelers
- 17 labelers
- Pharmacy cost
- $0.441 per capsule
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 3
Highlights of the vancomycin record
Vancomycin (Vancocin Hydrochloride) · label of June 7, 2024
Used for
From the label: indicationsVancomycin Hydrochloride for Injection is a glycopeptide antibacterial indicated in adult and pediatric patients (neonates and older) for the treatment of: • Septicemia ( 1.1 ) • Infective Endocarditis ( 1.2 ) • Skin and Skin Structure Infections ( 1.3 ) • Bone Infections ( 1.4 ) • Lower Respiratory Tract Infections ( 1.5 ) To reduce the development of drug-resistant bacteria and maintain the effectiveness of […]
On the market
- Earliest approval on file
- April 15, 1986
- Generic labelers
- 31 labelers
- Pharmacy cost
- $1.33 per capsule
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 49
Source: FDA drug labels via openFDA (Ampicillin label of February 21, 2025, Vancomycin label of June 7, 2024); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do ampicillin and vancomycin differ on the record?
In FDA's classes, ampicillin is a penicillin-class antibacterial and vancomycin a glycopeptide antibacterial.
Half-life, in each label's words: Ampicillin, “Due to maturational changes in renal function, ampicillin half-life decreases as postmenstrual age (a sum of …”; Vancomycin, “The mean elimination half-life of vancomycin from plasma is 4 to 6 hours in subjects with normal renal function.”
Generics: ampicillin since 1971; vancomycin since 1964 (Drugs@FDA).
| Ampicillin | Vancomycin | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | Bacterial infections, Diarrhea |
| Pharmacologic class | Penicillin-class Antibacterial | Glycopeptide Antibacterial |
| How it works (label) | n/a | Vancomycin is an antibacterial drug [see Microbiology (12.4) ]. |
| Half-life (label) | Due to maturational changes in renal function, ampicillin half-life decreases as postmenstrual age (a sum of gestational age and postnatal age) increases for infants with postnatal age of less than 28 days. | The mean elimination half-life of vancomycin from plasma is 4 to 6 hours in subjects with normal renal function. |
| Earliest approval on file (Drugs@FDA) | December 29, 1966 | April 15, 1986 |
| First generic approved | March 3, 1971 | November 6, 1964 |
| Generic labelers (NDC) | 17 labelers | 31 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.441 per capsule (Ampicillin 500 mg capsule) | $1.33 per capsule (Vancomycin HCl 125 mg capsule) |
| 12-month price change | -8% | +4% |
| Boxed warning | No | No |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
| Recalls recorded | 3 | 49 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 8,240 | 65,529 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to ampicillin
- every medicine labeled for the same conditions