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1st generation Spectra of Activity
- Good Gram + activity (resistant to B-lactamases)
- Limited Gram - activity (covers some enteric bacilli, poor B-lactamase resistance)
- Anaerobe activity limited to PCN susceptible strains (in oropharnyx)
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1st Generation pharmacokinetics
- High bioavailability of oral agents (food doesn't affect abs)
- Good distribution throughout body but little CNS penetration
- Primarily renally eliminated
- Short half-life
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-
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2nd generation pharmacokinetics
- Good oral bioavailability
- (Cefuroxime axetil should be given w/ food)
- Good distribution (only cefuroxime penetrates CNS)
- Renally eliminated
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2nd generation Spectrum of Activity
- Gram + aerobes: not as active as 1st gen, primarily streptococci and staphylococci activity
- Gram - aerobes: Improved activity from 1st gen against enteric bacilli (E.coli, Klebsiella, Enterobacter, Proteus)Good activity against some B-lactamase producers (Haemophilus, Moraxella)
- Anaerobes: limited overall. Exception: cephamycins (cefoxitin, cefotetan, cefmetazole)
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ceftriaxone (Rocephin)
3rd generation (IV)
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3rd generation pharmacokinetics
- Good bioavailability of oral agents
- (cefpodoxime & cefditoren should be given with food)
- Good distribution throughout body (CNS penetration)
- Primarily renally eliminated (except ceftriaxone & cefoperazone- 30-45% renal, remainder in bile)
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3rd generation Spectrum of Activity
- Gram+ aerobes: primarily streptococci and staphylococci, less active than other generations.
- Gram- aerobes: Active against wide variety of organisms but still subject to inactivation by B-lactamases. (Excellent against Enterobacteriacae, Haemophilus, Moxarella, Neisseria)
- Ceftazidime good against pseudomonas
- Anaerobes: Limited to oropharyngeal strains
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4th generation Spectrum of Activity
- Good Gram+ activity.
- Excellent Gram- activity, inc pseudomonas aeruginosa
- More stable against B-lactamases especially those made by enterobacteriaceae.
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4th Generation pharmacokinetics
- IV only- 100% bioavailability
- Good CNS penetration
- Short half-life
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Cephalosporin Adverse Effects
- GI: n/v, abd pain, diarrhea
- Skin: rash
- CNS: stimulatory (tremors, insomnia, seizures)
- Neutropenia, thrombocytopenia
- Hypersensitivity in 1-3% pts
- Ceftriaxone- billiary sludging
- Agents w/NMTT side chain- hypoprothombinemia, disulfiram-like rxn (cefoperazone, cefmandole, cefotetan, cefmetazole)
- C.diff, superinfection
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