Antibiotic Substitutions
Not all agents are routinely tested by microbiology labs against all organisms. This is especially true of oral antibiotics as intravenous agents are often used as the reference for the entire drug class. Generally, the following agents from the same drug class can be used in place of the reference agent that is reported on the antibiogram. The table below can be used to assist with some common substitution issues.
| Considering using: | Use reference susceptibility reported on Antibiogram: | Notes: |
|---|---|---|
| Amoxicillin | Penicillin | Amoxicillin exhibits less resistance than penicillin for S. pneumoniae |
| Amoxicillin/clavulanate | Ampicillin/sulbactam | Amoxicillin/clavulanate may not have coverage for Acinetobacter; Amoxicillin/clavulanate has better coverage of E. coli than ampicillin/sulbactam |
| Azithromycin | Erythromycin | |
| Cefadroxil | Cefazolin | |
| Cephalexin | Cefazolin | |
| Cefdinir | Ceftriaxone | Neisseria infections not covered by cefdinir |
| Cefditoren | Ceftriaxone | |
| Cefpodoxime | Ceftriaxone | |
| Ceftibuten | Ceftriaxone | |
| Clarithromycin | Erythromycin | |
| Dicloxacillin | Oxacillin | |
| Doxycycline | Tetracycline | |
| Minocycline | Tetracycline | |