Penicillins and Cephalosporins

Question 1

Penicillin G - what specific type of organisms does it tx?

Answer 1

Antimicrobial - good for gram (+) organisms; high dose given IV

Question 2

Penicillin G - MOA

Answer 2

Inhibits transpeptidase –> blocks cell wall synthesis

Question 3

Penicillin G - MOR (2)

Answer 3

1. Penicillinase

2. Beta-lactamase

Question 4

Amoxicillin; Ampicillin - MOA

Answer 4

Antimicrobial

Inhibition of cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking –> activity against gram +/- bacteria

Question 5

Amoxicillin; Ampicillin - MOR

Answer 5

Beta-lactamase

Question 6

What do you tx using amoxicillin-clavulanate (oral)?

Answer 6

Uncomplicated cystitis, uncomplicated pyelonephritis

Question 7

What do you tx w/ampicillin + gentamicin (IV)?

Answer 7

Uncomplicated and complicated pyelonephritis –> esp. by Enterococcus or extremely ill

Question 8

What 2 UT pathogens make the most common (90% outpatient)?

Answer 8

E. coli and Klebsiella

Question 9

Piperacillin; Ticarcillin - MOA

Answer 9

Antimicrobial

Inhibit cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking –> activity against gram +/- aerobic/anaerobic bacteria

Question 10

Piperacillin and Ticarcillin are used in combo w/

Answer 10

Used together with a beta-lactamase inhibitors tazobactam/clavulanate –> effective against Pseudomonas aeruginosa

Question 11

Piperacillin-tazobactam and Ticarcillin-clavulanate are used for Tx of….

Answer 11

Complicated pyelonephritis (IV), extremely ill

Question 12

Piperacillin; Ticarcillin - Toxcity

Answer 12

Defect of hemostasis

Question 13

Imipenem-Cilastatin - MOA (only Imipenem)

Answer 13

Antimicrobial

MOA: Imipenem inhibits cell wall synthesis by binding penicllin binding protein, preventing peptidoglycan crosslinking

Question 14

Imipenem-Cilastatin - Why Paired

Answer 14

Paired w/ Cilastatin (DHP-I inhibitor)-> inhibits renal enzyme dehydropeptidasein in PCT brush border=> prevents Imipenem break down

Question 15

Imipenem-Cilastatin - Tx

Answer 15

Very resistant to chromosomal beta-lactamases; Broad spectrum ; Treatment of complicated pyelonephritis (IV) (and extremely ill)

Question 16

Aztreonam - MOA

Answer 16

Antimicrobial

Prevents cell wall synthesis by binding penicllin binding protein, preventing peptidoglycan cross-linking

Question 17

Aztreonam - Tx what type of bacteria?

Answer 17

Activity only against gram-negative bacteria; effective against Enterobacteriaceae and P. aeruginosa

Question 18

Aztreonam - MOR

Answer 18

Resistant to plasmid extended spectrum beta-lactamases (but not chromosomal); ;

Question 19

Aztreonam - Tx

Answer 19

Treatment of uncomplicated pyelonephritis (IV) or septicemia in extremely ill pts

Question 20

Ceftriaxone - Class

Answer 20

Antimicrobial –> 3rd generation cephalosporin

Question 21

Ceftriaxone - MOA

Answer 21

Interferes w/ cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan cross-linking

Question 22

Ceftriaxone - MOR

Answer 22

Beta-lactamase

Question 23

Ceftriaxone - Tx

Answer 23

Given IV every 12-24 hours; half-life = 8hrs

Tx of suspected septicemia and uncomplicated pyelonephritis (oral, sensitivities known)

Question 24

Ceftriaxone - Effective against…

Answer 24

Effective against S. aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa

Question 25

Cefepime - Class

Answer 25

Antimicrobial –> 4th generation cephalosporin

Question 26

Cefepime - MOA

Answer 26

Interferes w/ cell wall synthesis by binding penicillin binding protein, preventing peptidoglycan crosslinking; ;

Question 27

What makes Cefepime better than Ceftriaxone?

Answer 27

4th generation cephalosporins even more resistant to beta-lactamases than 3rd generations

Question 28

Cefepime - MOR

Answer 28

Beta-lactamase

Question 29

Cefepime - Tx

Answer 29

Treatment of extremely ill pts and those w/ complicated pyelonephritis (IV)

Question 30

Clavulanate - MOA/Class

Answer 30

Beta-lactamase Inhibitor

Suicide inhibitor that irreversibly binds and inhibits beta-lactamase

Question 31

Tazobactam - MOA/Class

Answer 31

Beta-lactamase Inhibitor
Poor activity against the inducible chromosomal beta-lactamases
Good activity against the plasmid beta-lactamases