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8 Cards in this Set
- Front
- Back
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Penicillin Action Mechanism
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Inhibit cell wall synthesis by covalently binding to PBPs and inhibiting the D-D-transpeptidation (loose end of pentaglycan attached to side-chain); structural abn. leads to cell lysis
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Mechanisms of beta-lactam resistance
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1. altered PBPs -- decr. affinity for beta-lactams
2. inability to penetrate to site of action (e.g., Gram(-)) 3. incr. expression of efflux pumps 4. beta-lactamase |
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Penicillin G
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Abs: low acid stability; food interference; max. conc. after 30-60m use only if proven efficacious; typically given parenterally --
Distr: 60% bound to albumin; signif. amt appears in bile, kidney, liver, semen, lymph, intestine Elim: by kidney; 10% glom, 90% tub. secr. Spec: cellulitis, endocarditis, gonorrhea, pneumonia, strep, syphilis, meningococci |
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Penicillin V
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Abs: orally active; yield 2-5x more plasma conc. than G
Spec: tonsillitis, pharyngitis, skin inf. (strep. pyogenes), odontogenic inf. |
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isoxazoyl penicillins: oxocillin, cloxacillin, dicloxacillin,
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Abs: rapid, but incomplete; increases on empty stomach
Dist: Elim: rapidly by kidney; some hepatic Spec: narrow; beta-lactamase resistant; good against beta-lactamase staph. |
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Aminopenicillins
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- ampicillin/amoxicillin
- broader Gram (-) spec. than PenG - amox. has better oral absorption than ampi, - covers enterococci |
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beta-lactamase resistant penicillins (IV)
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-methicillin/nafcillin/oxacillin
- R: IV - I: Skin infections -- S. aureus; S. epidermidis |
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oral beta-lactamase resistant
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- cloxacillin/dicloxacillin
- R: oral - I: skin infections -- S. aureus; S. epidermidis |
