Fluoroquinolones Flashcards

1
Q

What is the MOA of fluoroquinolone?

A

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

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2
Q

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

A

Topoisomerase IV

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3
Q

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

A

DNA Gyrase (Topoisomerase II)

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4
Q

Which of the FQs is used against Gram + aerobes?

A

Levofloxacin, Moxifloxacin, Gemifloxacin

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5
Q

Which of the FQs is used against Gram - aerobes?

A

Ciporfloxacin = Levofloxacin > Moxifloxacin

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6
Q

What FQs should NOT be used for Pseudomonas?

A

Moxifloxacin

Gemifloxacin

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7
Q

What FQ should be used for anaerobes?

A

Moxifloxacin

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8
Q

What FQs should be used for atypical bacteria?

A

All of the FQs

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9
Q

What are the pharmokinetics of FQs?

A

Concentration-dependent bactericidal activity

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10
Q

What are the mechanisms of resistance to FQs?

A

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

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11
Q

What is the old FQ that is still in use?

A

Ciprofloxacin

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12
Q

What are the new FQs?

A

Levofloxaxin
Moxifloxacin
Gemifloxacin

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13
Q

What FQs have good Gram + activity?

A

The newer ones.

Levofloxaxin
Moxifloxacin
Gemifloxacin

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14
Q

What is the best FQ against anaerobes?

A

Moxifloxacin

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15
Q

Which of the FQs has good CSF penetration?

A

Moxifloxacin

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16
Q

What FQs are used for CA pneumonia?

A

Levofloxaxin
Moxifloxacin
Gemifloxacin

17
Q

What FQs are used for HCA pneumonia?

A

Ciprofloxacin (add a Gram + antibiotic)

Levofloxacin

18
Q

What FQs are used to treat UTIs and prostatitis?

A

Ciprofloxacin

Levofloxacin

19
Q

What FQs are used to treat sinusitis and bronchitis?

A

All of them

20
Q

What FQs are used to treat TB?

A

Levofloxacin

Moxifloxacin

21
Q

How are intrabdominal infections treated?

A

Use of a FQ alongside metronidazole for anaerobe coverage

22
Q

What is used to treat Pseudomonas?

A

Ciprofloxacin

23
Q

What are the SE of FQs?

A

GI problems
QT elongation
Tendonitis
Tendon rupture

24
Q

What population should FQs NOT be used in?

A

Pregnant women

25
Q

What are the drug interactions of FQs?

A

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

26
Q

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

A

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

27
Q
  • 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
A

• A. Ciprofloxacin

28
Q

What is the MOA of metronidazole?

A

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

29
Q

What are the pharmokinetics of metronidazole?

A

Metronidazole displays concentration-dependent bactericidal activity

30
Q

What are the mechanisms of resistance to metronidazole?

A
  • 􏰀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
31
Q

What is the spectrum of activity of metronidazole?

A

Anaerobes

Peptostreptococcus spp.
Bacteroides spp. (ALL)* 
Fusobacterium 
Prevotella spp. 
Clostridium spp. (ALL)* 
Helicobacter pylori
32
Q

What are the administration methods of metronidazole?

A

IV or oral

33
Q

What is the main metabolism of metronidazole?

A

Liver

34
Q

What is metronidazole the drug of choice for?

A

Moderate C. difficile infection

35
Q

What are the main SEs of metronidazole?

A

GI problems - nausea/vomiting

Peripheral neuropathy

36
Q

What is the interaction of metronidazole and warfarin?

A

It will increase the anticoagulant effect of warfarin

37
Q

Are the FQs removed in hemodialysis?

A

No

38
Q

Is metronidazole removed in hemodialysis?

A

Yes