Quinolone
Gram positive bacteria: methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Listeria monocytogenes
Gram negative bacteria: Enterobacteriaceae, H. influenzae, other Haemophilus spp., N. gonorrhoeae, N. meningitides, M. catarrhalis, P. aeruginosa, Stenotrophomonas maltophilia, S. maltophilia
Atypicals: Legionella pneumophilia
Inhibition of topoisomerase (DNA gyrase) enzymes, which inhibits relaxation of supercoiled DNA and promotes breakage of double stranded DNA.
Fluoroquinolones produce both concentration-dependent (peak:MIC), and a combination of concentration and time-dependent killing (AUC:MIC).
500mg dose; Cmax: 6mg/ml; Volume of distribution: 1.45 L/kg; Table 2
CNS: headache, insomnia, dizziness; hallucinations, depression, psychotic reactions (rare)
Connective tissue: tendon injury
Renal: interstitial nephritis
Cardiovascular: QTC prolongation, torsades de pointes, arrhythmias
Oral: 250mg, 500mg, 750mg tablet
Intravenous: 25mg/ml solution
Opthalmic: 0.5% solution
Inhalational anthrax, postexposure prophylaxis: 500 mg PO/IV every 24 hr for 60 days
Chronic bronchitis: 500 mg PO/IV every 24 hr for 7 days
Chronic prostatitis: 500 mg PO/IV every 24 hr for 28 days
Community-acquired pneumonia: 500 mg PO/IV every 24 hr for 7-14 days or 750 mg PO/IV or every 24 hr for 5 days
Nosocomial pneumonia: 750 mg PO/IV every 24 hr for 7-14 days
Pyelonephritis: 250 mg PO/IV every 24 hr for 10 days
Sinusitis: 500 mg PO/IV every 24 hr for 10-14 days
Skin/skin structure infection: uncomplicated, 500 mg PO/IV every 24 hr for 7-10 days; complicated, 750 mg PO/IV every 24 hr for 7-14 days
Urinary tract infection: uncomplicated, 250 mg PO/IV every 24 hr for 3 days; complicated, 250 mg IV or ORALLY every 24 hr for 10 days
Conjunctivitis, bacterial: (0.5% ophthalmic solution) day 1-2, 1-2 drops every 2 hr while awake (MAX 8 times/day); day 3-7, 1-2 drops every 4 hr while awake (MAX 4 times/day)
Corneal ulcer: (1.5% ophthalmic solution) day 1-3, 1-2 drops every 30 min to 2 hr while awake and 4 hr and 6 hr after retiring; day 4 through treatment end, 1-2 drops every 1 to 4 hr while awake
Conjunctivitis, bacterial: (0.5% ophthalmic solution) ages 1 year and older; day 1-2, 1-2 drops every 2 hr while awake (MAX 8 times/day); day 3-7, 1-2 drops every 4 hr while awake (MAX 4 times/day)
Corneal ulcer: (1.5% ophthalmic solution) ages 6 year and older; day 1-3, 1-2 drops every 30 min to 2 hr while awake and 4 hr and 6 hr after retiring; day 4 through treatment end, 1-2 drops every 1 to 4 hr while awake
Renal failure:
Respiratory indications: CrCl 20 – 49ml/min: 500mg x 1, then 250mg q 24 hours
CrCl 10 – 19ml/min: 500mg x 1, then 250mg q 48 hours
Hemodialysis/peritoneal dialysis: 500mg x 1, then 250mg q 48 hours
Hepatic failure: No dosing changes recommended at this time.
Precautions:
Prolongation of QT interval; avoid concurrent use with other drugs that prolong QT interval and in patients with risk factors for torsades de pointes (hypokalemia, significant bradycardia, cardiomyopathy)
Patients with glucose 6-phosphate dehydrogenase deficiency
Diabetes mellitus; disturbances of blood glucose have been reported, usually in diabetic patients receiving concomitant treatment with an oral hypoglycemic agent or with insulin
Divalent cations: aluminum, magnesium zinc, iron, calcium, antacids, sucralfate – reduced bioavailability of quinolones (can cause therapeutic failure)
Theophylline, caffeine, xanthines: clearance of these is inhibited with fluoroquinolones
Category C: Risk unknown. Human studies inadequate.
Therapeutic: Culture and sensitivities, signs and symptoms of infection
Toxic: Urinalysis, BUN, SCr, AST and ALT, Physicial examination: encephalopathic changes