PHARMACO - Chloramphenicol Flashcards Preview

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Flashcards in PHARMACO - Chloramphenicol Deck (87)
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1

?S ribosomes in bacteria

70

2

?S ribosomes in mammalians

80

3

 Basis for selective toxicity against microorganisms without causing major effects on mammalian cells
3 Differences

 Ribosomal subunits
 Chemical composition
 Functional specificities of component nucleic acids and proteins

4

General MoA

Bactericidal

5

General binding at what ribosome

50S except for tetracycline

6

 Inhibits transpeptidation (catalyzed by peptidyl transferase)

chloramphenicol

7

 Blocks the binding of aminoacyl moiety of tRNA to mRNA complex so the peptide at the donor site cannot be transferred to the amino acid acceptor

chloramphenicol

8

 Bind at 50S-block translocation of peptidyl-tRNA from the acceptor site to the donor site

 Macrolides, telithromycin, and clindamycin

9


 Bind to 30S

 Tetracyclines

10

 Blocks the binding of amino-acid-charged tRNA to the acceptor site

 Tetracyclines

11

 Constrict the exit channel on the ribosome through which polypeptides are extruded tRNA synthase activity is inhibited

 Streptogramins

12

inhibits tRNA synthase activity

 Streptogramins

13

bactericidal AB which bind to the 50S

 Streptogramins

14

 Bacteriostatic
 Binds to a unique site at 50S
 Blocks formation of tRNA-ribosome-mRNA complex

 Linezolid

15

Broad spectrum

chloramphenicol
tetracycline

16

moderate spectrum

macrolides
ketolides

17

narrow spectrum

lincosamides
streptogramins
linezolid

18

newer antibiotics

streptogramins
linezolid

19

Are there other antimicrobial drugs in chloramphenicol class

No

20

RoA of Chloramphenicol

 Oral as well as parenteral

21

Tissue distribution of Chloramphenicol

Distributed throughout all tissues

22

Crosses placental and blood-brain barriers

Chloramphenicol

23

Undergoes enterohepatic cycling

Chloramphenicol
tetracycline

24

Enzyme that inactivates chloramphenicol

hepatic glucoronosyltransferase

25

Does Chloramphenicol undergo enterohepatic cycling

Yes

26

Fraction excreted in urine unchanged or changed in chloramphenicol?

unchanged

27

MoA of Chloramphenicol

 Bacteriostatic

28

When does Chloramphenicol become bactericidal

 H. influenzae
 N. meningitidis
 Bacteroides

29

Is chloramphenicol effective for chlamydia

No

30

Resistance to chloramphenicol

 Plasmid mediated-formation of acetyl- transferases that inactivate the drug

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