Two medicines, side by side
Ampicillin vs ceftriaxone
Ampicillin and ceftriaxone are both labeled for bacterial infections and urinary tract infections. Drugs@FDA records approvals of ampicillin since 1966 and of ceftriaxone since 1984. Pharmacies paid $0.441 per ampicillin 500 mg capsule and $1.44 per ceftriaxone 1 g vial (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 ceftriaxone a cephalosporin antibacterial.
Check it at the source: the ampicillin FDA label on DailyMed (effective February 21, 2025); the ceftriaxone FDA label on DailyMed (effective February 4, 2026).
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 ceftriaxone record
Ceftriaxone (Rocephin) · label of February 4, 2026
Used for
From the label: indicationsBefore instituting treatment with Ceftriaxone for injection, USP, appropriate specimens should be obtained for isolation of the causative organism and for determination of its susceptibility to the drug. Therapy may be instituted prior to obtaining results of susceptibility testing. […]
On the market
- Earliest approval on file
- December 21, 1984
- Generic labelers
- 16 labelers
- Pharmacy cost
- $1.44 per vial
Supply and safety
- Shortage
- No current entry
- Recalls
- 20
Source: FDA drug labels via openFDA (Ampicillin label of February 21, 2025, Ceftriaxone label of February 4, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do ampicillin and ceftriaxone differ on the record?
In FDA's classes, ampicillin is a penicillin-class antibacterial and ceftriaxone a cephalosporin 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 …”; Ceftriaxone, “Based on middle ear fluid ceftriaxone concentrations in the 23 to 25 hour and the 46 to 50 hour sampling time …”
Generics: ampicillin since 1971; ceftriaxone since 1987 (Drugs@FDA).
| Ampicillin | Ceftriaxone | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | Urinary tract infections, Bacterial infections |
| Pharmacologic class | Penicillin-class Antibacterial | Cephalosporin Antibacterial |
| How it works (label) | n/a | Microbiology: Mechanism of Action Ceftriaxone is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. |
| 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. | Based on middle ear fluid ceftriaxone concentrations in the 23 to 25 hour and the 46 to 50 hour sampling time intervals, a half-life of 25 hours was calculated. |
| Earliest approval on file (Drugs@FDA) | December 29, 1966 | December 21, 1984 |
| First generic approved | March 3, 1971 | April 30, 1987 |
| Generic labelers (NDC) | 17 labelers | 16 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.441 per capsule (Ampicillin 500 mg capsule) | $1.44 per vial (Ceftriaxone 1 g vial) |
| 12-month price change | -8% | -4% |
| Boxed warning | No | No |
| Shortage now | A presentation being discontinued | No current entry |
| Recalls recorded | 3 | 20 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 8,240 | 38,242 |
| 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