Fluoroquinolones

Agents

  • Ciprofloxacin (Cipro) (see Ciprofloxacin, [[Ciprofloxacin]])
  • Gatifloxacin (Tequin) (see Gatifloxacin, [[Gatifloxacin]])
  • Gemifloxacin (Factive) (see Gemifloxacin, [[Gemifloxacin]])
  • Grepafloxacin (Raxar) (see Grepafloxacin, [[Grepafloxacin]]): withdrawn from worldwide markets in 1999
  • Levofloxacin (Levaquin) (see Levofloxacin, [[Levofloxacin]])
  • Moxifloxacin (Avelox, Avalox, Avelon) (see Moxifloxacin, [[Moxifloxacin]])
  • Ofloxacin (Floxin, Ocuflox) (see Ofloxacin, [[Ofloxacin]])
  • Sitafloxacin (Gracevit) (see Sitafloxacin, [[Sitafloxacin]])
  • Sparfloxacin (Spacin, Zagam) (see Sparfloxacin, [[Sparfloxacin]]): withdrawn from US market
  • Tosufloxacin (Ozex) (see Tosufloxacin, [[Tosufloxacin]])
  • Trovafloxacin (Trovan, Turvel) (see Trovafloxacin, [[Trovafloxacin]]): withdrawn from US market

Pharmacology

  • Fluoroquinolone Antibiotics

Gram-Negative Coverage

  • Fluoroquinolones Have Adequate Activity Against Enteric Gram-Negative Rods
    • General Spectrum of Gram-Negative Rod Activity: levofloxacin had same overall spectrum of activity again Gram-negative rods as ofloxacin, but is 2x more potent
    • Pseudomonas Aeruginosa: levofloxacin has less activity against than ciprofloxacin
    • Pseudomonas Aeruginosa/Serratia/Providencia/Proteus: moxifloxacin has less activity against these organisms than ciprofloxacin

Gram-Positive Coverage

  • Newer Fluoroquinolones Have Increased Activity Against Streptococcus Pneumoniae and Other Gram-Positive Organisms, as Compared to Ciprofloxacin
    • Methicillin-Sensitive Staphylococcus Aureus (MSSA): levofloxacin/moxifloxacin/gemifloxacin are active
    • Methicillin-Sensitive Staphylococcus Epidermidis (MSSE): levofloxacin/moxifloxacin/gemifloxacin are active
    • Methicillin-Resistant Staphylococcus Aureus (MRSA): have high levels of resistance to ciprofloxacin and newer fluoroquinolones
    • Methicillin-Resistant Staphylococcus Epidermidis (MRSE): have high levels of resistance to ciprofloxacin and newer fluoroquinolones
    • Enterococcus: levofloxacin/moxifloxacin activities are marginal

Anerobic Coverage

  • Moxifloxacin is the Only Currently Available Agent Which Has Clinically-Significant Anaerobic Coverage
    • Bacteroides Species: anaerobic activity of moxifloxacin has been shown to be comparable to that of piperacillin-tazobactam (Zosyn) and amoxicillin-clavulanic acid (Augmentin)
      • However, resistance rates may be as high as 25-30% in some centers

Respiratory Pathogen Coverage

  • Streptococcus Pneumoniae: newer fluoroquinolones have increased activity against Streptococcus Pneumoniae and other Gram-positive organisms, as compared to ciprofloxacin
    • Gemifloxacin Has Unusually High Activity Against Streptococcus Pneumoniae, as Compared to Other Fluoroquinolones
  • Haemophilus Influezae/Moraxella Catarrhalis/Legionella Pneumophila/Mycoplasma Pneumoniae/Chlamydophila Pneumoniae: all newer fluoroquinolones have good activity against these pathogens

Adverse Effects

Cardiovascular Adverse Effects

Q-T Prolongation with Definite Association with Torsade (see Torsade, [[Torsade]])

  • Epidemiology: fluoroquinolones have a definite association with torsade
    • However, the risk of Q-T prolongation with fluoroquinolones is mainly related to additive effects with other Q-T prolonging drugs, as the risk when used alone is small
  • Physiology: dose-dependently block cardiac voltage-gated potassium channels -> delay in cardiac repolarization
    • Class Effect
  • Risk of Q-T Prolongation
    • High Risk
      • Gatifloxacin (Tequin) (see Gatifloxacin, [[Gatifloxacin]])
      • Grepafloxacin (Raxar) (see Grepafloxacin, [[Grepafloxacin]])
      • Moxifloxacin (Avelox, Avalox, Avelon) (see Moxifloxacin, [[Moxifloxacin]])
      • Sparfloxacin (see Sparfloxacin, [[Sparfloxacin]])
    • Medium Risk
      • Gemifloxacin (see Gemifloxacin, [[Gemifloxacin]])
      • Levofloxacin (Levaquin) (see Levofloxacin, [[Levofloxacin]])
      • Ofloxacin (Floxin, Ocuflox) (see Ofloxacin, [[Ofloxacin]])
      • Sitafloxacin (Gracevit) (see Sitafloxacin, [[Sitafloxacin]])
      • Tosufloxacin (Ozex) (see Tosufloxacin, [[Tosufloxacin]])
    • Low Risk

Pulmonary Adverse Effects

Drug-Induced Pulmonary Eosinophilia (see Drug-Induced Pulmonary Eosinophilia, [[Drug-Induced Pulmonary Eosinophilia]])

Other Adverse Effects

  • Tendon Rupture

References

  • Torsade de pointes probably induced by sparfloxacin. J Assoc Physicians India. 2002 Aug;50:1077-8 [MEDLINE]
  • Levofloxacin-Induced Torsades de Pointes. Tex Heart Inst J. 2010;37(2):216-7 [MEDLINE]