Streptogramin Antibiotics and Oxazolidinone Antimicrobial Agents Flashcards Preview

Pharmacology Test #2 > Streptogramin Antibiotics and Oxazolidinone Antimicrobial Agents > Flashcards

Flashcards in Streptogramin Antibiotics and Oxazolidinone Antimicrobial Agents Deck (28)
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1

Synercid is a mixture containing?

30% quinupristin and 70% dalfopristin

2

Are quinupristin and dalfopristin useful on their own?

No, each of these compounds is bacteriostatic alone, but bactericidal in combination

3

Dalfopristin MOA

directly interferes with the peptidyl transferase-catalyzed step

4

What reaction does peptidyl transferase (ribosomal RNA) catalyze?

catalyzes the formation of a peptide bond between the two amino acids present in the ribosome

5

Quinupristin MOA

binds in the ribosomal tunnel and causes blockage of the tunnel

6

Syncercid is used IV for treatment of:

1. Vancomycin-resistant Enterococcus faecium bacteremia
2. Skin infections caused by MRSA
3. Vancomycin-resistant Enterococcus faecium urinary tract infections

7

Most common resistance to quinupristin is due to?

adenine methylation of A2058 in the 23S rRNA as in the case of erythromycin and clindamycin

8

What can resistance to Streptogramin also be caused by?

resistance can also be due to efflux and enzymatic inactivation (metabolism) by resistant bacteria

9

What is Streptogramin likely to be reserved for?

reserved for serious life-threatening infections caused by gram (+) organisms

10

Mild side effects of synercid?

inflammation and pain at the site of injection, nausea, diarrhea, muscle weakness and rash

11

Drug interactions of Streptogramins

Streptogramins inhibit cytochrome CYP3A4

12

CYP3A4 metabolizes

warfarin, diazepam, astemizole, terfenadine, cisapride, non-nucleoside reverse transcriptase inhibitors and cyclosporine

13

Oxazolidinones are a novel class of antimicrobials that act by

inhibiting protein synthesis

14

MOA of linezolid?

acts early by potent interaction with 50S ribosomal subunit

15

In the initiation step of bacterial translation, the 50S subunit associates with?

associates with fMet-tRNA and a complex composed of the 30S ribosomal subunit and mRNA to form the functional 70S initiation complex

16

What does linezolid have affinity for?

the 50S subunit - no affinity to the 30S subunit

17

Linezolid interaction with the 50S subunit does what?

prevents the formation of the 70S initiation complex

18

Which rRNA does linezolid specifically interact with?

the 23S rRNA

19

Linezolid is used to treat:

1. Vancomycin-resistant Enterococcus faecium
2. Nosocomial pneumonia caused by methacillin - resistant strains of Staphylococcus aureus
3. Skin infections caused by methicillin-resistant strains of Staphylococcus aureus

20

Emergence of linezolid resistant has been reported in which species?

Enterococcus species, MRSA, and E. coli

21

Other mild reported side effects of linezolid?

headache, tongue discoloration and oral Monilia (Candida) infections

22

More serious side effects of linezolid?

thrombocytopenia, GI bleeding and anemia

23

Long-term treatment of linezolid resulted in?

fully reversible myelosuppression and linezolid-induced neuropathy

24

What should be monitored weekly in patients receiving linezolid?

complete blood counts

25

Linezolid is a reversible, nonselective inhibitor of

monoamine oxidase

26

Patients taking linezolid should not consume large quantities of?

food or beverages that are rich in tyramine (cheese, red wine) in order to avoid a significant pressor response

27

Because of drug interactions, linezolid has the potential for interaction with?

adrenergic and serotonergic agents

28

What has been observed when linezolid is administered to normotensive subjects?

a reversible potentiation of pressor response to pseudoepherine