LEVOFLOXACIN, A 2ND-GENERATION FLUOROQUINOLONE

Levofloxacin, levo-isomer of the D,L-racemate ofloxacin, is a new fluo roquinolone antibiotic approved for use in the United States in Decemb er 1996. It has an extended spectrum of activity compared with older-g eneration fluoroquinolones (ciprofloxacin, ofloxacin), with improved a ctivity against gram-positive bacteria and excellent activity against gram-negative bacteria and atypical organisms. Although its activity a gainst anaerobic organisms is improved over that of earlier fluoroquin olones, levofloxacin should not be considered a first-line anaerobic a gent. It is available in an injectable form, as well as an oral formul ation with virtually 100% oral bioavailability. The plasma elimination half-life ranges from 6-8 hours in individuals with normal renal func tion. Approximately 80% of drug is eliminated unchanged in urine throu gh glomerular filtration and tubular secretion. The pharmacokinetics a re not appreciably affected by age, gender, or race when differences i n renal function and body mass and composition are taken into account. Levofloxacin had impressive efficacy in clinical studies of community -acquired pneumonia, acute bacterial exacerbations of chronic bronchit is, acute sinusitis, skin and skin structure infections, and complicat ed urinary tract infections and pyelonephritis. It is well tolerated; its adverse event profile is similar to that of other fluoroquinolones , with gastrointestinal and central nervous system effects reported mo st commonly. Drug interactions are uncommon with levofloxacin; however , coadministration with antacids or with other agents containing dival ent or trivalent cations reduces levofloxacin absorption. The agent sh ould prove to be more effective than older fluoroquinolones, especiall y for infections caused by pneumococci highly resistant to penicillin.