Fluoroquinolones Flashcards
MOA of Fluoroquinolones
Bactericidal
- Inhibit DNA gyrase (Topoisomerase II)
- Mainly in gram (-) bacteria
- prevents relaxation of positively supercoiled DNA - Inhibits Topoisomerase IV
- Mainly in gram (+) bacteria
- prevents separation of replicated chromosomal DNA
Describe the two mechanisms of resistance to Fluoroquinolones due to mutation.
- Mutation of GyrA or GyrB genes that code for gyrase or mutation in ParC or ParE genes that code for Topoisomease IV. Mutation lowers affinity for the drug to bind and inhibit the enzymes.
- Mutation in the efflux pump or porins decreasing the concentration of the drug in the bacterial cell.
Describe the two mechanisms of Plasmid-mediated resistance to Fluoroquinolones.
- Plamids contain a qnr gene that protects the gyrase and topoisomerase IV
- Plasmid contains aminoglycoside acetyltransfease enzyme that modifies the drug and inactivates it
Which two FQs work against gram negatives
Ciprofloxacin
Levofloxacin
Which two FQs work against gram positives
Moxifloxacin
Gemifloxacin
(levo also woks against +’s)
Which of the 4 FQs work well against anaerobes?
Moxi
Which FQ is not metabolized in the kidneys and where is it metabolized?
Moxi
-Liver
The three FQs that are metabolized in the kidneys are also great for what type of infection?
UTIs
Which two drugs are great for serious Nosocomial infections?
Cipro, Levo
-they have a good safety rating especially for anthrax, GU infection and prostatits
What are cardiovascular and dematologic side effects of FQs?
Cardio: QT prolongation
Derm: photosensitivity, Stephen Johnson syndrome
What MSK side effects can occur while taking FQs and why?
Tendonitis or tendon rupture and/or arthropathy
-drugs can affect collagen formation and can damage cartilage
What neuro side effects do FQs have and why?
Peripheral Neuropathy
-drugs can inhibit GABA and adenosine receptors and result in permanent nerve damage
