Antibiotic Classes

Beta Lactam Drugs

- most common
- diverse
- bactericidal
- inhibits synthesis of peptidoglycan

Penicillin- Natural

Gram positive spectrum

Penicillin- penicillinase resistant

- Gram positives
- adds side chain
- methilicillin, oxacillin

Penicillin- Extended spectrum

- Gram positive and negative
- amoxicillin, ampicillin

Penicillin Co-drugs

Combination of b-lactam with b-lactamase inhibitor
- augmentin

Cephalosporins

resemble penicillin but can withstand b-lactamase
- can be modified

Cephalosporin 4th and 5th generation

affect both Gram positive and negative

Monobactams

- gram negative
- aztreonam

Carbapenems

- similar to third gen cephalosporin
- imipenem

Cell wall targets have no

side effects because human cells lack cell walls

Cell membrane inhibitors

- create leakage
- topical use
- bacitracin or polymyxins

Glycopeptides

interfere with cross-linking in peptidoglycan chains
- G+
- Vancomycin

Fosfomycin

- stops cell wall synthesis
- UTIs
- not for children

Quinolones

- inhibit DNA gyrase
- Nalidixic acid for UTIs
- fluoroquinolones for broader spectrum

Sulfonamides

- inhibit folic aicd
- UTIs
- photosensitive and forms sulfa crystals

Nitrofurantoin

- interferes with enzyme and protein synthesis

- UTIs

- Proteus is resistant

Rifampin

- inhibits RNA polymerase
- treats TB
- causes discoloration (red orange)

Flagyl (metronidazole)

- prevents synthesis of nucleic acids

- anaerobes

- parasites (Trichomonas)

Aminoglycosides

- interfere with 30s ribosome
- oto and nephro toxic
- for serious Gram +
- inpatient drug to monitor peaks and troughs

Tetracycline

- interfere with 30s ribosome subunit
- broad spectrum
- photosensitive
- deposits in bone and teeth
- decrease normal flora= secondary infection

Macrolides

- interfere with 50s subunit
- older= G+; new= broad
- accumulate in WBCs for good for intracellular infections
- heart on liver, heart, and GI

Chloramphenicol

- interfere with 50s subunit
- only gram negative infections
- can cross blood brain barrier (meningitis)
- aplastic anemia and bone marrow aplasia (grey baby syndrome)