Fluoroquinolones

Question 1

What is the MOA of fluoroquinolone?

Answer 1

Inhibition of DNA synthesis via inhibition of DNA gyrase and topoisomerase IV

Question 2

What is the main enzyme targeted by FQs in Gram (+)?

Answer 2

Topoisomerase IV

Question 3

What is the main enzyme targeted by FQs in Gram (-)?

Answer 3

DNA Gyrase (Topoisomerase II)

Question 4

Which of the FQs is used against Gram + aerobes?

Answer 4

Levofloxacin, Moxifloxacin, Gemifloxacin

Question 5

Which of the FQs is used against Gram - aerobes?

Answer 5

Ciporfloxacin = Levofloxacin > Moxifloxacin

Question 6

What FQs should NOT be used for Pseudomonas?

Answer 6

Moxifloxacin

Gemifloxacin

Question 7

What FQ should be used for anaerobes?

Answer 7

Moxifloxacin

Question 8

What FQs should be used for atypical bacteria?

Answer 8

All of the FQs

Question 9

What are the pharmokinetics of FQs?

Answer 9

Concentration-dependent bactericidal activity

Question 10

What are the mechanisms of resistance to FQs?

Answer 10

Altered target sites
Efflux of the drug
Change in cell wall permeability

Question 11

What is the old FQ that is still in use?

Answer 11

Ciprofloxacin

Question 12

What are the new FQs?

Answer 12

Levofloxaxin
Moxifloxacin
Gemifloxacin

Question 13

What FQs have good Gram + activity?

Answer 13

The newer ones.

Levofloxaxin
Moxifloxacin
Gemifloxacin

Question 14

What is the best FQ against anaerobes?

Answer 14

Moxifloxacin

Question 15

Which of the FQs has good CSF penetration?

Answer 15

Moxifloxacin

Question 16

What FQs are used for CA pneumonia?

Answer 16

Levofloxaxin
Moxifloxacin
Gemifloxacin

Question 17

What FQs are used for HCA pneumonia?

Answer 17

Ciprofloxacin (add a Gram + antibiotic)

Levofloxacin

Question 18

What FQs are used to treat UTIs and prostatitis?

Answer 18

Ciprofloxacin

Levofloxacin

Question 19

What FQs are used to treat sinusitis and bronchitis?

Answer 19

All of them

Question 20

What FQs are used to treat TB?

Answer 20

Levofloxacin

Moxifloxacin

Question 21

How are intrabdominal infections treated?

Answer 21

Use of a FQ alongside metronidazole for anaerobe coverage

Question 22

What is used to treat Pseudomonas?

Answer 22

Ciprofloxacin

Question 23

What are the SE of FQs?

Answer 23

GI problems
QT elongation
Tendonitis
Tendon rupture

Question 24

What population should FQs NOT be used in?

Answer 24

Pregnant women

Question 25

What are the drug interactions of FQs?

Answer 25

Divalent and trivalent cations will impair oral absorption of FQs Warfarin + FQ will cause prolonged bleeding Theophylline/Cyclosporine + FQ will cause a buildup of the former and lead to toxicity

Question 26

49 yo female was admitted with a UTI. Urine culture is positive for E.Coli >100,000 colonies sensitive to fluoroquinolones. Which of the following is NOT appropriate treatment. • A. Ciprofloxacin • B. Levofloxacin • C. Moxifloxacin

Answer 26

• C. Moxifloxacin - it doesn't enter into the urine

Question 27

* 24yo male is admitted with community acquired pneumonia. CXR shows a right middle lobe infiltrate. Sputum cultures are positive for Streptococcus pneumoniae sensitive to FQ’s. Which of the following in NOT appropriate treatment. * A. Ciprofloxacin * B. Levofloxacin * C. Moxifloxacin * D Gemifloxacin

Answer 27

• A. Ciprofloxacin

Question 28

What is the MOA of metronidazole?

Answer 28

Ultimately inhibits DNA synthesis 􏰁- Prodrug that is activated by a reductive process 􏰁- Selective toxicity against anaerobic and microaerophilic bacteria due to the presence of ferredoxins within these bacteria 􏰁- Ferredoxins are proteins that donate electrons to form highly reactive nitro anion that damages bacterial DNA, inhibit DNA synthesis, and cause cell death

Question 29

What are the pharmokinetics of metronidazole?

Answer 29

Metronidazole displays concentration-dependent bactericidal activity

Question 30

What are the mechanisms of resistance to metronidazole?

Answer 30

- 􏰀Altered growth requirements – organisms grows in higher local oxygen concentrations causing decreased activation of metronidazole 􏰀- Altered ferredoxin levels – reduced transcription of the ferredoxin gene; less activation of metronidazole

Question 31

What is the spectrum of activity of metronidazole?

Answer 31

Anaerobes ``` Peptostreptococcus spp. Bacteroides spp. (ALL)* Fusobacterium Prevotella spp. Clostridium spp. (ALL)* Helicobacter pylori ```

Question 32

What are the administration methods of metronidazole?

Answer 32

IV or oral

Question 33

What is the main metabolism of metronidazole?

Answer 33

Liver

Question 34

What is metronidazole the drug of choice for?

Answer 34

Moderate C. difficile infection

Question 35

What are the main SEs of metronidazole?

Answer 35

GI problems - nausea/vomiting | Peripheral neuropathy

Question 36

What is the interaction of metronidazole and warfarin?

Answer 36

It will increase the anticoagulant effect of warfarin

Question 37

Are the FQs removed in hemodialysis?

Answer 37

No

Question 38

Is metronidazole removed in hemodialysis?

Answer 38

Yes