Quinolones

Antibacterials

Ciprofloxacin

2nd

inhibition of prokaryotic topoisomerase II (DNA gyrase) and topoisomerase IV→ DNA supercoiling → formation of double-stranded breaks → inhibition of DNA replication and transcription (bactericidal effect)

good

• Primarily renal (via glomerular filtration and tubular secretion)

• Moxifloxacin undergoes biliary excretion.

• Absorption is reduced when coadministered with polyvalent cations (e.g., magnesium, calcium, iron).

• Norfloxacin, ciprofloxacin, and ofloxacin

  • Gram-negative rods causing urinary and gastrointestinal infections

  • Some gram-positive pathogens

  • Genitourinary infections caused by Neisseria gonorrhoeae, Chlamydia trachomatis, and/or Ureaplasma urealyticum

  • Ciprofloxacin: Pseudomonas aeruginosa (e.g., malignant otitis externa)

• Levofloxacin, moxifloxacin, and gemifloxacin:

  • Atypical bacteria (e.g., Legionella spp., Mycoplasma spp., Chlamydophila pneumoniae)

  • Also effective against anaerobes

  • Gemifloxacin is highly potent against penicillin-resistant pneumococci.

  • Moxifloxacin: 2nd-line treatment of tuberculosis in patients who cannot tolerate antitubercular drugs and in multidrug resistant tuberculosis

• GI upset

• Neurological symptoms

  • Mild headache

  • Dizziness

  • Mood changes

  • Peripheral neuropathy

  • Can lower seizure threshold (increased risk in patients taking NSAIDs and those with a previous history of epilepsy)

• Hyperglycemia/hypoglycemia

• QT prolongation

• Photosensitivity

• Skin rash

• Superinfection (most commonly with gram-positive pathogens) [58][59]

• Potentially life-threatening exacerbations in patients with myasthenia gravis [60]

• In children: potential damage to growing cartilage → reversible arthropathy

• Muscle ache, leg cramps, tendinitis, tendon rupture, especially of the Achilles tendon (the risk of tendon rupture is higher for individuals over 60 years of age and for individuals on steroid therapy)

increased risk for drug interactions as ciprofloxacin inhibits cytochrome P450

• Children and teenagers < 18 years of age

• Patients > 60 years of age and those taking cortisol

• Pregnant women

• Breastfeeding women

• Epilepsy, stroke, CNS lesions/inflammation

• QT prolongation

• Myasthenia gravis

• Cautious use in patients with:

  • Renal failure

  • Hepatic failure

  • Antacid use [61]

  • Known aortic aneurysm or increased risk of aneurysms (e.g., Marfan syndrome, Ehlers-Danlos syndrome, advanced age, peripheral atherosclerotic disease, hypertension)

• Chromosome-encoded mutation in DNA gyrase and topoisomerase IV enzymes

• Altered cell wall permeability

• Plasmid-encoded mutations in efflux pump proteins