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Flashcards in 9.1 Sulfa Deck (24):
1

Broadly speaking, what is the mechanism of sulfa drugs?

Prevent folate synthesis- which is necessary for nuclei acid production

2

What are the 2 mechanisms sulfa drugs use?

Sulfamethoxazole mimic PABA --> competitively inhibits DHT synthetase

Trimethoprim (TMP) – analog of dihydrofolate --> DHF reductase

3

What is the IV sulfa drug?

Trimethroprim – sulfamethoxazole

4

What are the PO sulfa drugs?

Trimethroprim – sulfamethoxazole (TMP-SMZ)/Bactrim/Septra
Dapsone
Sulfisoxazole/erythromycin (Pediazole)

5

What G+ coverage do Sulfa drugs have?

Strep
Staph
Listeria

6

What G+ are NOT covered by Sulfa? Why?

Enterococcus- Can bring in folate from host

7

What G- coverage do sulfa drugs have?

H. flu
Enterobacteriaceae

8

What is Dapsone used for?

Leprosy/ mycobacterium leprae

9

What are the common side effects of Sulfa?

GI effects
Fever
Rash (including Stevens-Johnson syndrome)
Leukopenia
Thrombocytopenia
Hepatitis
Hyperkalemia

10

What are special risks with Dapsone?

Hemolysis
Methemoglobinemia = decreased ability of RBC to carry O2

11

What was the first Quinilone?

Nalidixic acid

12

What G+ coverage does Nalidixic acid have?

Staph aureus
Strep

13

What G- coverage does Nalidixic acid have?

E. coli

14

What is the mechanism of Nalidixic acid against G+/G-?

G+: Topoisomerase
G-: DNA gyrase
= both interfere with unwinding of DNA

15

What are the IV quinolones?

-oxacin
Ciprofloxacin
Levofloxacin
Moxifloxacin

16

What are the PO quinolones?

-oxacin
Ciprofloxacin
Levofloxacin
Moxifloxacin
Gemifloxacin
Ofloxacin

17

How do bacteria become immune to quinilones?

Mutation of topoisomerase IV/gyrase
Overexpression of reflux pumps

18

What is the spectrum for Quinilones?

G+ = strep, staph
G- = H. Flu, Enterobacteriacea, Neisseria
Anaerobic = Clostridia, Bacteroids
Atypical = Chlamydia, Mycoplasma, Legionella
Mycobacteria = TB, MAC, Mycobacterium leprae

19

What does Cipro cover?

R1 = piperazine – enhance G- activity (similar to PCN)
Covers Pseudomonas
Weak G+ activity – Not to treat Strep Pneumo infection
Many atypical
Some mycobacteria

20

What does Levofloxacine cover?

2x more potent than ofloxacin
Less active against G- than Cipro
Covers Pseudomonas
More active against G+ than Cipro
Ok for strep pneumo including PCN resistant

21

What is the difference between cipro/levo?

Cipro- more G-, weaker G+, pseudomonas
Levo- More G+, weaker G-

22

What do Moxifloxin and Gemifloxacin cover?

Enhance activity against strep pneumo including PCN resistant
Atypical
Less active against G- (i.e. pseudomonas)
Good coverage for anaerobes

23

What populations are quinilones contraindicated with?

Peds
Pregnancy

24

What are the SA of quinilones?

QT prolongation
Achilles rupture
+ risk for C Diff
N/V/D, abd pain
Headache/dizzy
Rash