Fluoroquinolones

Question 1

What are the second generation fluoroquinolones?

Answer 1

Enrofloxacin, difloxacin, orbifloxacin, marbofloxacin, danofloxacin

Question 2

Is ciprofloxacin for human or veterinary use? Pradofloxacin?

Answer 2

Human

Question 3

What are most Baytril (Enrofloxacin) breakpoints & clinical studies in small animals for?

Answer 3

UTI

Question 4

Can you use fluoroquinolones extra-label in food animals?

Answer 4

NO

Question 5

Can you use enrofloxacin in dairy cattle?

Answer 5

If they are less than 20 months yes, but not over 20 months or veal calves

Question 6

What is the indication for enrofloxacin use in food animals?

Answer 6

BRD, swine respiratory disease

Question 7

Can you use Danofloxacin in cattle? What disease?

Answer 7

Beef only for BRD, no dairy or veal

Question 8

Are fluoroquinolones natural or synthetic?

Answer 8

Fully synthetic (antimicrobial)

Question 9

Are fluoroquinolones lipid soluble or water soluble? Small or large Vd?

Answer 9

Very lipid soluble, very high Vd

Question 10

Are fluoroquinolones bactericidal or bacteristatic?

Answer 10

Bactericidal

Question 11

How do fluoroquinolones work?

Answer 11

Topoisomerase inhibition (topoisomerase enzyme)

Question 12

What is the spectrum of fluoroquinolones? (What are they referred to as?)

Answer 12

Oral aminoglycosides
Gram+ aerobes: ++
Gram - aerobes: +++++

Question 13

Are mammalian topoisomerases affected by fluoroquinolones?

Answer 13

No

Breaks bacterial DNA strands

Question 14

Which fluoroquinolone includes anaerobes?

Answer 14

Pradofloxacin

Question 15

Will enrofloxacin be active against mycoplasma, erlichia & rickettsia?

Answer 15

Yes

Question 16

What are the 2 mechanisms of resistance for fluoroquinolones

Answer 16

Alteration of target enzymes (DNA gyrase & topoisomerase IV) and decreased drug permeation in to bacterial cells by efflux pumps

Question 17

How does resistance start in fluoroquinolones?

Answer 17

mutations in DNA gyrase leading to 2 - 4x MIC values

Question 18

Which bacteria has 3rd generation cephalosporin & plasmid-mediated fluoroquinolone resistance?

Answer 18

Salmonella Heidelberg

Question 19

Which bacteria had the first reported plasmid-mediated fluoroquinolone resistance?

Answer 19

K. pneumoniae

Question 20

Which bacteria have single step mutations that confer resistance to new fluoroquinolones?

Answer 20

Staph aureus & pseudomonas

Question 21

What is a mutant selection window?

Answer 21

Low level resistance due to using fluoroquinolones at MIC to 10x MIC in-vitro

Question 22

What is the mutant prevention concentration?

Answer 22

The concentration above which 2 concurrent mutations for resistance must occur for an organism to grow

Question 23

What is the bioavailability or oral fluoroquinolones? IM? SQ?

Answer 23

All above 80%

Question 24

When are peak plasma conceontrations of fluoroquinolones reached in the dog?

Answer 24

30 min - 1 hour

Question 25

What are 2 tissues that have diffusional barrier to antimicrobials? DO these tissues reach therapeutic concentrations?

Answer 25

Brain, prostate | Yes

Question 26

What is the primary elimination route of fluoroquinolones?

Answer 26

Kidney

Question 27

The liver biotransforms enrofloxacin to what in animals?

Answer 27

Ciprofloxacin

Question 28

Which fluoroquinolone is excreted 80% in feces (biliary)?

Answer 28

Difloxacin

Question 29

Is oral ciprofloxacin as bioavailable as oral enrofloxacin?

Answer 29

No. Only 50%

Question 30

What is the efficacy of fluoroquinolones associated with?

Answer 30

Peak concentration & ratio of AUC to MIC (AUIC)

Question 31

What is the peak concentration to pathogen MIC ratio target?

Answer 31

8 - 10x MIC

Question 32

What is the purpose of this target?

Answer 32

Preventing proliferation of first step resistant mutants

Question 33

What is the minimum target for AUC to pathogen MIC? What is this equation?

Answer 33

125 | 24hr AUC / pathogen MIC = 125+

Question 34

If the ratio is 125+, can there be 100% efficacy with a 24Q dose?

Answer 34

Yes

Question 35

Which species are susceptible to articular cartilage damage from enrofloxacin?

Answer 35

Puppies in rapid growth @ high doses | Foals

Question 36

What are the 2 biggest concerns for using enrofloxacin in cats?

Answer 36

Retinal degeneration | Phototoxicity

Question 37

Which 2 drugs can prolong enrofloxacin levels?

Answer 37

Furosemide, Cemetedine

Question 38

What is the max amount of enrofloxacin you should give a cat per day to reduce risk of blindness?

Answer 38

5mg/kg

Question 39

What is the issue with administering enrofloxacin to a dog with a history of epilepsy?

Answer 39

Decrease seizure threshold

Question 40

Why should pradofloxacin not be used in dogs?

Answer 40

Bone marrow suppression. Thrombocytopenia & neutropenia

Question 41

What drugs can enrofloxacin have interactions with?

Answer 41

Drugs that are substrate for CP450 (phenobarbital)

Question 42

Ciprofloxacin raise the serum level of what in humans?

Answer 42

Theophylline

Question 43

Can you use enrofloxacin as an intra-uterine infusion for a mare with pyometra?

Answer 43

No

Question 44

What are the 2 fluoroquinolones you can use in cattle for BRD?

Answer 44

Enrofloxacin, Danofloxacin

Question 45

What is the 1 fluoroquinolone you can use in swine for respiratory disease?

Answer 45

Enrofloxacin

Question 46

What 3 fluoroquinolones can you use in cats for skin infections?

Answer 46

Enrofloxacin, marbofloxacin, orbifloxacin

Question 47

What are the 4 fluoroquinolones you can use in dogs for skin infections?

Answer 47

Difloxacin, enrofloxacin, marbofloxacin, orbifloxacin

Question 48

What is the 1 fluororquinolone you can use in dogs for respiratory disease?

Answer 48

Enrofloxacin

Question 49

What are the 4 fluoroquinolones you can use in dogs for a UTI?

Answer 49

Enrofoxacin, difloxacin, marbofloxacin, orbifloxacin