Exam 8: Fluoroquinolones Flashcards Preview

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Flashcards in Exam 8: Fluoroquinolones Deck (30)
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1
Q

What are 3 common fluoroquinolone formulations? What generation is each?

A

Ciprofloxacin (2nd)
Levofloxacin (3rd)
Moxifloxacin (4th)

2
Q

What is the mechanism of fluoroquinolones?

A

They target DNA gyrate (Gram negatives) and DNA Topoisomerase IV (Gram positives)
Humans don’t have Gyrase, but we do have a Topoisomerase (II) that could be affected at SUPER high concentrations

3
Q

Are fluoroquinolones -cidal or -static?

A

Bactericidal

4
Q

What is an advantage of each generation of fluoroquinolones?

A

2nd- Good for systemic infections, Pseudomonas
3rd- Good against Strep and atypicals
4th- Good against anaerobes, gram positive and negative aerobes

5
Q

What causes antibiotic resistance to fluoroquinolones?

A
  1. Plasmid encoded Quinolone resistance proteins (Qnr) shield enzymes from drug
  2. Plasmid encoded Efflux pumps
  3. Chromosomal mutations that modify quinolone binding sites
6
Q

What is an important principle about Fluoroquinolone resistance?

A

If a bug is resistant to one fluoroquinolone, it’s probably resistant to all of them

7
Q

What resistance mechanism do aminoglycosides share with Ciprofloxacin?

A

Plasmid encoded aminoglycoside acetyltransferase can modify Cipro too…

8
Q

What can inhibit absorption of fluoroquinolones?

A

Polyvalent ions (Calcium , zinc, iron, aluminum)

9
Q

What can’t moxifloxacin treat?

A

UTI because it is metabolized by the liver, not found in urine

10
Q

What are 3 “respiratory fluoroquinolones”?

A

Levofloxacin
Moxifloxacin
Gemifloxacin

11
Q

What bugs can respiratory fluoroquinolones cover?

A

Strep pneumo
Staph aureus (not if it’s Oxacillin resistant)
Mycoplasma pneumoniae
Legionella pneumophila

12
Q

fluoroquinolones are the only orally administered antibiotics that are effective against ________? In whom are they useful?

A

Pseudomonas

Good for managing Pseudomonas in CF patients

13
Q

How should fluoroquinolones be used in treating Pseudomonas? Why?

A

For acute exacerbations, not for chronic therapy.

We don’t want to cause resistance.

14
Q

Which fluoroquinolone can’t treat UTIs?

A

Moxifloxacin

15
Q

What are 3 GU infections that fluoroquinolones can treat? What don’t we use them to treat?

A

UTIs
Prostatitis
Chlamydia
NOT for syphilis or N. gonorrhoeae

16
Q

Why can’t we use fluoroquinolones for gonorrhea anymore?

A

Resistance became a big problem

17
Q

What are 3 GI infections we can treat with fluoroquinolones?

A

Traveler’s diarrhea
Shigella
Salmonella

18
Q

What is a consideration when treating traveler’s diarrhea?

A

Be careful, because fluoroquinolones can induce expression of Shiga-like toxin

19
Q

Why are fluoroquinolones good for soft tissue infections? What is a soft tissue infection that they shouldn’t be used to treat?

A

Really good tissue penetration
Osteomyelitis, joint infections, diabetic ulcers.
They should NOT be used to treat MRSA (resistance could be bad)

20
Q

When would you use fluoroquinolones to treat TB?

A

MDR TB or TB in HIV patients

21
Q

What is a rare use of flourquinolones? Which one is used?

A

Anthrax (Bacillus anthracis)

Ciprofloxacin

22
Q

A terrorist sprays your patient in the face with some weird powder, but you don’t know what it is. Treatment?

A

Ciprofloxacin

Treatment for anthrax

23
Q

What is the most common side effect of fluoroquinolones?

A

Nausea, GI distress

24
Q

What is a serious side effect of fluoroquinolones?

A

C diff.

Heavy fluoroquinolone use probably selected for toxic strains of Clostridium difficile

25
Q

What is a CNS side effect of fluoroquinolones?

A

GABA-A antagonism

Increased use of seizure

26
Q

What is the black box warning for fluoroquinolones?

A

Chondrotoxicity

Makes people prone to tendon rupture (Achilles)

27
Q

In whom are fluoroquinolones contraindicated? Why?

A
Pregnant women (damage bones/joints of the fetus)
Children 
Arthropathy was observed in animal models (chondrotoxicity)
Maybe no real danger in the long term though
28
Q

What are 3 adverse effects of fluoroquinolones?

A

C diff
Seizures (GABA antagonism)
Chondrotoxicity

29
Q

Who are most prone to the chondrotoxicity effects of fluoroquinolones?

A

Old patients
People on corticosteroids
Solid organ transplant patients

30
Q

What increases the risk of seizures associated with fluoroquinolones.

A

NSAID use