Lecture 16 - Fluoroquinolone

What are the characteristics of Fluoroquinolones? (-static/-cidal, time/concentration, etc)

-Bacteriocidal

-Concentration dependent

-PAE

What is the spectrum of activity of fluoroquinolones?

-Most aerobic gram (-)

-Some aerobic gram (+)

What is the biggest issue with Fluoroquinolones?

Rapid emergence of resistance

What is the mechanism of action of fluoroquinolones?

Inhibit bacterial DNA gyrase (inhibits DNA replication and transcription)

What are the two most common resistance to fluoroquinolone?

-Mutations to DNA gyrase enzyme

-Decreased bacterial cell permeability

How is the absorption of fluoroquinolone?

-Absorbed well orally

-Decreased absorption with cations

How is the distribution of fluoroquinolone?

-Good penetration into deep tissue

-Enrofloxacin can penetrate CNS and prostate

-Passes placental barrier and found in milk

Where is fluoroquinolone metabolized and eliminated?

-Renal elimination

-Secreted as active form in urine

-Difloxacin liver excretion

What are the common toxicities associated with fluoroquinolones?

-Mild GI upset

-Decreases seizure threshold

-Phototoxicity

-Retinal degeneration in cats (can cause permanent blindness)

-Arthropathy (vesicles on articular surface) and decreased bone growth in juveniles

What animals should you not use fluoroquinolones in?

-Pregnant/lactating animals

-Growing animals (especially large breeds)

-Animals with hx/risk of seizures

-Athletes

What are the therapeutic uses of fluoroquinolones in dogs and cats?

-UTI

-Serious infections caused by gram (-) bacteria

-Respiratory tract infections

-Ophthalmic infections caused by gram (-) bacteria

-Prostatitis

What are the therapeutic uses of fluoroquinolones in small mammals?

-Skin and visceral infections

-Do not cause GI disturbances and enteritis

What are the therapeutic uses of fluoroquinolones in large animals?

-Bovine respiratory disease complex (only approved for food animals)

-Any gram (-) bacterial infection in horses

What are the extra label use laws with fluoroquinolones in large animals?

Vets are prohibited from extra label use in food producing animals