8.5 Flashcards Preview

270 S1 > 8.5 > Flashcards

Flashcards in 8.5 Deck (31):
1

What is the difference between ketolides and macrolides?

Ketolides bind to 2 RNA domain vs macrolides bind to only 1.
= kotolides bind tighter, harder to efflux

2

What are ketolides used for? Spectrum?

Respiratory infections
strep, staph
H. flu, Pertussis
Atypical: Chlamydia, Mycoplasma, and Legionella

3

What are the toxicities of ketolides?

Erythromycin – GI – N/V/D; Phlebitis
QT prolongation
Erythromycin and Clarithromycin – Cyp 3A4 inhibitors
Blurred vision, diplopia, difficulty focusing
Severe liver damage

4

What is the mechanism of tetracyclines and Glycylcyclines?

Bind to 30s and prevent protein synthesis

5

How do bugs become resistant to TCN?

Efflux pumps
Ribosomal mutation

6

What is the spectrum of TCN?

Strep pneumo, staph aureus
H. flu, Neisseria
Atypical: Rickettsia, Chlamydia, Mycoplasma, Borrelia, Treponema

7

What TCN is PO and IV?

Doxycycline

8

What does minocycline treat?

MRSA
Leprosy

9

How are Glycylcyclines different than TCNs?

Glycl amide group- prevents recognition by efflux pump

10

What is the coverage of glycylcyclines?

G+: Strep, Staph (including MRSA), Enterococci (including VRE)
G-: H. Flu, Neisseria, Enterobacteriacea
Anarobes: B. fragilis and many other
Atypical: Mycoplasma

11

What are the toxicities of TCNs?

Rings structure – a potent chelator of metal ions gray to yellow discoloration of growing teeth and bone
Contraindicated for pregnant women
Cautious for children <8y.o
Rashes, anaphylaxis
Blue-black hyperpigmentation – minocycline
Photosensitivity
N/V
Hepatoxicity

12

What is the mechanism of Choramphenicol?

Binds to 50s, blocks formation of peptide bonds

13

If a bug is resistant to Choramphenicol, what else is it likely resistant to?

also resistant to macrolides/ketolides, clindamycin *******
**These drugs are all similar, if resistant to one, likeley resistant to all

14

How do bugs become resistant to Choramphenicol?

Producing enz acetylates chloramphenicol  prevent binding to target
Efflux pumps

15

What is the spectrum of chloramphenicol?

Strep
H. Flu, Neisseria, Salmonella, Shigella
**Anaerobes – B fragilis and other
**Atypical – Mycoplasma, Chlamydia, Rickettsia

16

What are the toxicities of chloramphenicol?

Reversible bone marrow suppression – dose dependent
Bind to mitochondrial ribosome
Irreversible aplastic anemia – occurs after completion a of therapy
Neonates – caused “gray baby syndrome”
Not fully functional liver enz (i.e UDP-glucuronyl transferase) accumulation of unmetabolized chloramphenicol
Optic neuritis

17

What is the mechanism of clindamycin?

Binds to 50s, inhibits protein synthesis
Similar to macrolides

18

If a bug is resistant to clindamycin, what else is it likely resistant to?

macrolides

19

What is the spectrum of clindamycin?

G+: Strep, staph
Anaerobes: B. Fragilis, Clostridium, and most other

**Most G- intrinsically resistant

20

What are the toxicities of clindamycin?

Induce C diff colitis – 0.01 -10%
Diarrhea
Rashes

21

What is the mechanism of Streptogramins?

2 different macrocyclic compounds
Binds to 50S prevent protein synthesis
Each compound has moderate antibacterial effects
Dalfopristin binds to ribosome -> induce conformational change -> enhance binding of quinupristin

22

What other Abx binding sites do streptogramins overlap with?

Macrolides
Clindamycin

23

What is the coverage of streptogramins?

Covers G+ only (i.e. strep, staph, and enterococcus)

24

What are the toxicities of streptogramins?

CYP450 inhibitor

Phlebitis – should be given via central line
Arthralgia, myalgias
Hyperbilirubinemia

25

What is the mechanism of linezolid?

Prevents 30s from joining with 50s= ribosome can't form

26

How do bugs become resistant to linezolid?

Mutation of ribosome
Efflux pumps

27

What is the spectrum of linezolid?

G(+) – strep, staph including MRSA and VRE

28

When is linezolid used? How dosed?

Reserved for VRE, MRSA
PO/IV = bioavalibility

29

What are the toxicities of linezolid?

N/V/D
Thrombocytopenia
Anemia, leukopenia – reversible
Not be given with MAO inhibitors
Together with SSRI serotonin syndrome

30

What is the spectrum for nitrofuratonin/macrobid?

Staph enterococcus
UTI only, need good renal fxn

31

What are the toxicities of nitrofuratonin/macrobid?

N/V, rash, interstitial pneumonitis, hepatitis, hemolytic anemia, and neuropathy