Fluoroquinolones

Fluoroquinolones were a previously widely used class of antibiotics that have become less commonly used due to the side effect profile.  Fluoroquinolones inhibit the DNA gyrase enzyme, which relaxes and weakens the bacterial DNA.  Fluoroquinolones also inhibit the topoisomerase IV enzyme, which results in interference of the separation of DNA during cell division.  Fluoroquinolones are primarily used in the treatment of respiratory and urinary tract infections. Adverse effects include tendinopathy, prolonged QTc interval, psychosis, neurotoxicity, phototoxicity, and should be avoided in pediatric, pregnant, and breastfeeding patients. 

Class Drugs

• Ciprofloxacin

• Levofloxacin

• Moxifloxacin

• Ofloxacin

Class Mechanism of Action

Inhibits DNA gyrase

• Relaxes and weakens DNA

Inhibition of topoisomerase IV

• Interferes with separation of DNA during cell division

Bacteriostatic/bactericidal

Class Applications

Respiratory and Urinary infections primarily

Organisms treated

• Gram (+) cocci

S. pneumoniae

• Gram (+) bacilli

Bacillus anthracis

• Gram (-) rods

Enterobacter

• E. coli

• H. influenzae

• Legionella

• Proteus

• Klebsiella

• Pseudomonas

• Shigella

• Atypical Infections

Class Adverse Effects

Resistance

• Mutations of topoisomerase IV and DNA gyrase

• Efflux pumps

• Decreased uptake

Hypersensitivity

• Rashes, angioedema, anaphylaxis

Tendinopathy

• Tendon rupture/tendinitis

Prolonged QT interval

Psychosis and neurotoxicity

Phototoxicity

C. difficile diarrhea

Avoid in pregnancy, pediatric patients, and breastfeeding

Drug Table

Drug Name	Application	Comments	Image
Ciprofloxacin			"Sip" "Row" "Flock"
Levofloxacin			"Lever 2000" "Flock"
Moxifloxacin			"Moxy" "Flock"
Ofloxacin			"Olaf" "Flock"