Cell Wall Synthesis Inhibitors

Question 1

MOA for Penicillins

Answer 1

inhibit cell wall synthesis by interfering with formation of peptidoglycan layer

bind transpeptidase enzyme

bacteriocidal

Question 2

Natural Penicillins

Answer 2

Penicillin G (gram +)
Penillin V (gram +)

Question 3

Penillin G

Answer 3

Gram +
IV or intramuscular administration
destroyed in acidic environment of digestive tract

Question 4

Penicillin V

Answer 4

Gram +
Oral (more stable in acidic environment)
Take without food

Question 5

Aminopenicillins

Answer 5

Gram -
Ampicillin
Amoxicillin

Question 6

Ampicillin

Answer 6

Oral

Take with OUT food

Question 7

Amoxicilin

Answer 7

Oral

Take with or without food

Question 8

Penicillinase Resistant Penicillins

Answer 8

Gram +
Contain side groups that protect drugs from inactivation by B-lactamases
Methicillin, oxacillin, nafcillin (parenterally)
Dicloxicillin (orally)

Question 9

Parenteral Penicillinase Resistant Penicillins

Answer 9

Methicillin, oxacillin, nafcillin

Question 10

Oral Penicillinase Resistant Penicillins

Answer 10

Dicloxicillin

Question 11

Anti-pseudomonal Penicillins

Answer 11

Gram -
Extended spectrum penicillins
Ticarcillin, Mezlocillin, pipercillin–parenterally
Carbenicillin–orally (therapeutic levels only reached in urinary tract)

Question 12

Parenteral anti-pseudomonal penicillins

Answer 12

Ticarcillin, mezlocillin, pipercillin

Question 13

Oral anti-pseudomonal penicillins

Answer 13

Carbenicillin–therapeutic levels only reached in urinary tract–limited to UTI’s and prostatic infections

Question 14

Irreversible inhibitors of B-lactamases

Answer 14

NO anti-microbial activity by themselves!
must be combined with penicillins–> expanded coverage against B-lactamase producing organisms

Clavulanic acid, sulbactam, tazobactam

Question 15

Cephalosporins

Answer 15

Cell-wall synthesis inhibitors

Structurally resemble penicillins

Difference: B-lactam chemical backbone
Stable to changes in pH
Take with or without food

Question 16

Adverse Effects of Cephalosporins

Answer 16

Penicillin allergic patients may be hypersensitive to cephalosporins

GI irritation

Renal Toxicity–accumulation of drug may cause seizures

Disrupts normal flora–infections

Question 17

Carbapenems

Answer 17

Bacteriocidal

Inhibit cell wall synthesis

Resistant to B-lactamases (unique different stereochemical structure of B-lactam ring)

Imipenem/cilostatin
Doripenem
Ertapenem
Meropenem

Question 18

Telavancin

Answer 18

interferes with cell wall synthesis by binding D-Ala-D-Ala portion of cell-wall– blocks cross linking

Changes cell’s permeability–> may disrupt membrane potential

NOT affected by B-lactamases

Question 19

Vancomycin

Answer 19

Interferes with cell wall synthesis by binding D-Ala-D-Ala portion of cell walls

NOT affected by B-lactamases

Given by IV

Reserved for MRSA

“Red man syndrome”–temporary flushing of skin when drug is given at high concentration too rapidly

Question 20

Cycloserine

Answer 20

Gram +/-

Reserved to treat TB (mycobacterium tuberculosis)

Question 21

Polymyxin B

Answer 21

Gram - (except Proteus)

Cationic detergent–disrupts lipoproteins in bacterial cell wall, increasing permeability