Penicillins and Cephalosporins Flashcards
Tx of UTIs 15.22
Penicillin G - what specific type of organisms does it tx?
Antimicrobial - good for gram (+) organisms; high dose given IV
Penicillin G - MOA
Inhibits transpeptidase –> blocks cell wall synthesis
Penicillin G - MOR (2)
- Penicillinase
2. Beta-lactamase
Amoxicillin; Ampicillin - MOA
Antimicrobial
Inhibition of cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking –> activity against gram +/- bacteria
Amoxicillin; Ampicillin - MOR
Beta-lactamase
What do you tx using amoxicillin-clavulanate (oral)?
Uncomplicated cystitis, uncomplicated pyelonephritis
What do you tx w/ampicillin + gentamicin (IV)?
Uncomplicated and complicated pyelonephritis –> esp. by Enterococcus or extremely ill
What 2 UT pathogens make the most common (90% outpatient)?
E. coli and Klebsiella
Piperacillin; Ticarcillin - MOA
Antimicrobial
Inhibit cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking –> activity against gram +/- aerobic/anaerobic bacteria
Piperacillin and Ticarcillin are used in combo w/
Used together with a beta-lactamase inhibitors tazobactam/clavulanate –> effective against Pseudomonas aeruginosa
Piperacillin-tazobactam and Ticarcillin-clavulanate are used for Tx of….
Complicated pyelonephritis (IV), extremely ill
Piperacillin; Ticarcillin - Toxcity
Defect of hemostasis
Imipenem-Cilastatin - MOA (only Imipenem)
Antimicrobial
MOA: Imipenem inhibits cell wall synthesis by binding penicllin binding protein, preventing peptidoglycan crosslinking
Imipenem-Cilastatin - Why Paired
Paired w/ Cilastatin (DHP-I inhibitor)-> inhibits renal enzyme dehydropeptidasein in PCT brush border=> prevents Imipenem break down
Imipenem-Cilastatin - Tx
Very resistant to chromosomal beta-lactamases; Broad spectrum ; Treatment of complicated pyelonephritis (IV) (and extremely ill)
Aztreonam - MOA
Antimicrobial
Prevents cell wall synthesis by binding penicllin binding protein, preventing peptidoglycan cross-linking
Aztreonam - Tx what type of bacteria?
Activity only against gram-negative bacteria; effective against Enterobacteriaceae and P. aeruginosa
Aztreonam - MOR
Resistant to plasmid extended spectrum beta-lactamases (but not chromosomal); ;
Aztreonam - Tx
Treatment of uncomplicated pyelonephritis (IV) or septicemia in extremely ill pts
Ceftriaxone - Class
Antimicrobial –> 3rd generation cephalosporin
Ceftriaxone - MOA
Interferes w/ cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking
Ceftriaxone - MOR
Beta-lactamase
Ceftriaxone - Tx
Given IV every 12-24 hours; half-life = 8hrs
Tx of suspected septicemia and uncomplicated pyelonephritis (oral, sensitivities known)
Ceftriaxone - Effective against…
Effective against S. aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa
Cefepime - Class
Antimicrobial –> 4th generation cephalosporin
Cefepime - MOA
Interferes w/ cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan crosslinking; ;
What makes Cefepime better than Ceftriaxone?
4th generation cephalosporins even more resistant to beta-lactamases than 3rd generations
Cefepime - MOR
Beta-lactamase
Cefepime - Tx
Treatment of extremely ill pts and those w/ complicated pyelonephritis (IV)
Clavulanate - MOA/Class
Beta-lactamase Inhibitor
Suicide inhibitor that irreversibly binds and inhibits beta-lactamase
Tazobactam - MOA/Class
Beta-lactamase Inhibitor
Poor activity against the inducible chromosomal beta-lactamases
Good activity against the plasmid beta-lactamases
