Mechanisms of Action by Drug Class

Question 1

Aminoglycosides

Answer 1

Inhibit bacterial protein synthesis

bind to 30S ribosomal subunit

resulting in the defective bacterial cell membrane

Question 2

Carbapenems

Answer 2

Inhibit cell wall synthesis

Question 3

cephalosporins

Answer 3

inhibit cell wall synthesis

Question 4

Fluoroquinolones

Answer 4

Inhibit DNA Gyrase

Question 5

Glycopeptides

Answer 5

Inhibit bacterial cell wall synthesis

D-alanyl-D-alanine

Question 6

Lincosamides

Answer 6

Inhibit bacterial protein synthesis

reversibly bind to 50S ribosomal subunits

Question 7

Lipoglycopeptide

Answer 7

inhibit bacterial cell wall synthesis

blocking polymerization and cross-linking of peptidoglycan

Question 8

Lipopeptides

Answer 8

Inhibits intracellular synthesis of DNA, RNA, and protein

Question 9

Macrolide

Answer 9

Zithromax & Erythrocin
inhibit RNA dependent protein synthesis
Bind to 50S ribosomal subunit

Biaxin
Inhibit protein synthesis
binds to 50S ribosomal subunit

Question 10

Monobactam

Answer 10

Inhibits bacterial cell wall synthesis

Question 11

Nitroimidazole

Answer 11

Damage DNA

Flagyl
cause a loss of helical DNA structure and strand breakage

Tindamax
Prevents DNA synthesis

Question 12

Oxazolidinones

Answer 12

Inhibit protein synthesis

Zyvox
binds to bacterial 23S ribosomal RNA of the 50S subunit

Sivextro
binds to the 50S bacterial ribosomal subunit; prevents the formation of a functional 70S initiation complex

Question 13

Penicillins

Answer 13

Inhibit bacterial cell wall synthesis

Question 14

Pleuromutilin

Answer 14

Inhibit bacterial protein synthesis

Xanleta
Interacts with the A- and P- sites of the peptidyl transferase center in domain V of the 23s ribosomal RNA of the 50S subunit

Altabax
binds at a unique site on the ribosomal 50S subunit; prevents formation of active 50S ribosomal subunits by inhibiting peptidyl transfer and blocking P-site interactions at this site

Question 15

Polymixins

Answer 15

Damages to bacterial cytoplasmic membrane causing leakage

Question 16

Rifamycins

Answer 16

Inhibit nucleic (RNA or DNA) synthesis

Question 17

Streptogramins

Answer 17

Inhibit bacterial protein synthesis by binding to different sites on the 50S bacterial ribosomal subunit

Question 18

Sulfonamides

Answer 18

Sulfamethoxazole
Interferes with bacterial folic acid synthesis and growth via inhibition of dihydrofolic acid formation from para-aminobenzoic acid;

trimethoprim
inhibits dihydrofolic acid reduction to tetrahydrofolate resulting in sequential inhibition of enzymes of the folic acid pathway

Question 19

tetracyclines

Answer 19

Inhibit bacterial protein synthesis

Question 20

ethambutol (Myambutol)

Answer 20

Inhibits arabinosyl transferase resulting in impaired mycobacterial cell wall synthesis

Question 21

isoniazid

Answer 21

Inhibits the synthesis of mycoloic acids, an essential component of the bacterial cell wall.

Question 22

pyrazinamide (Tebrazid)

Answer 22

Lowers the pH of the environment; exact mechanism of action has not been elucidated

Question 23

secnidazole (Solosec)

Answer 23

After entering the bacterial cell, it is proposed that secnidazole interferes with bacterial DNA synthesis of susceptible isolates

Question 24

retapamulin (Altabax)

Answer 24

Inhibits normal bacterial protein biosynthesis by binding at a unique site (protein L3) on the ribosomal 50S subunit; prevents formation of active 50S ribosomal subunits by inhibiting peptidyl transfer and blocking P-site interactions at this site