Protein synthesis inhibitors

Question 1

How do AGs work?

Answer 1

They block translocation and termination of peptides

Question 2

How do tetracyclines work?

Answer 2

They block AA-tRNA

Question 3

How do macrolide work?

Answer 3

They lock translocation of peptides

Question 4

How do oxazolidinones (linezolid) work?

Answer 4

Block 50 S binding

Question 5

CLEan TAG

Answer 5

50s: chloramphenicol, clindamycin, linezolid, erythromycin
30s: tetracyclines and aminoglycosides

Question 6

Name the aminoglycosides

Answer 6

Gentamicin and tobramycin

Question 7

What are aminoglycosides good at covering?

Answer 7

aerobic GNRs

Question 8

What formulary is available for AGs?

Answer 8

Only IV

Question 9

What are the side effects of aminoglycosides?

Answer 9

Nephrotoxic and ototoxic. Lots of kids given gentamicin develop irreversible hearing loss which is why we don’t often use it.

Question 10

Describe concentration dependent killing versus time dependent killing

Answer 10

Concentration dependent=Exposure to higher concentration for a short time

Time dependent=Longer exposure with more dosings is more efficient

Question 11

Which drugs rely on concentration dependent killing?

Answer 11

Aminoglycosides
fluoroquinolones
metronidazole

Question 12

Which drugs rely on time dependent killing?

Answer 12

penicillins

Question 13

Extended interval dosing:

Answer 13

Give lots of smaller doses throughout the day to keep toxicity low but remain in efective range

Question 14

How to tetracyclines work?

Answer 14

They bind to 30S unit and block the aminoacyl tRNA too

Question 15

What are the major situations in which we would use a tetracycline?

Answer 15

Rocky mountain spotted fever and lyme dz

Question 16

How do macrolides develop resistance?

Answer 16

23S rRNA nucleotide mutation

Efflux

Question 17

When do we use macrolides?

Answer 17

Respiratory tract infections

Question 18

What is unique about the metabolism of macrolides?

Answer 18

They have a very long half life

Question 19

What are the side effects of macrolides?

Answer 19

Ototoxicity

Question 20

What do the macrolides cover?

Answer 20

1. GPC (staph and strep often resistant)
2. mycoplasma
3. legionella
4. chlamydia, mycobacteria
5. H. flu
   - –>basically all the atypicals

Question 21

How does clindamycin work?

Answer 21

Binds to 23S rRNA binding site, preventing peptide bond formation

Question 22

What drug should you NOT prescribe with clindamycin? Why?

Answer 22

Macrolides–because will have mutual interference

Question 23

Is clindamycin bacteriostatic or bacteriocidal?

Answer 23

bacteriostatic. Almost all of the protein synthesis inhibitors are bacteriostatic EXCEPT the aminoglycosides

Question 24

What is clindamycin effective against?

Answer 24

GPC and oral/bowel anaerobes

Question 25

How does linezolid work?

Answer 25

Prevents 50S from binding the 30S unit

Question 26

What is linezolid effective against?

Answer 26

VRE, VRSA, MRSA

Question 27

How do sulfa drugs work?

Answer 27

They inhibit dihydropteorate synthesis

Question 28

How does trimethoprim work?

Answer 28

Inhibits DHFR

Question 29

Is bactrim static or cidal?

Answer 29

static

Question 30

What are the contraindications to bactrim?

Answer 30

erythema multiforme rxn Pregnancy*** Can cause bone marrow suppression

Question 31

What is bactrim good for?

Answer 31

S pneumo H flu, E coli, pneumocystis

Question 32

How do fluoroquinolones work?

Answer 32

They inhibit DNA gyrase

Question 33

What are three mechanisms of resistance with fluoroquinolones?

Answer 33

1. Reduced binding to DNA topoisomerase (gyrase) 2. Protection by QnR protein 3. Impaired permeability and drug efflux

Question 34

Are fluoros cidal or static?

Answer 34

cidal

Question 35

Cipro is used for:

Answer 35

Uti and STD (mostly gram negative coverage) | --Cipro has better penetration of the urinary tract

Question 36

Mox/levo is used for:

Answer 36

pneumonia (good gram positive coverage too unlike cipro)

Question 37

How does metronidazole work?

Answer 37

Damages DNA by forming a nitro radical

Question 38

What is metronidazole used for?

Answer 38

Anaerobes (bowel, oral) C difficile infection Giardia Amoeba

Question 39

What are the side effects of metronidazole?

Answer 39

Metallic taste GI upset CNS: ataxia/vertigo teratogen

Question 40

How does Rifampin work?

Answer 40

Binds to RNA polymerase and inhibits

Question 41

What is Rifampin good for?

Answer 41

It's broad spectrum and good for: GP and GN coverage | Mycobacterium especially

Question 42

How does rifampin resistance develop?

Answer 42

Mutation of the RNA poly binding site. Resistance develops very easily, so never use alone

Question 43

How do you treat pertussis?

Answer 43

Azithromycin | --can also use bactrim