Levofloxacin (Levaquin)

  • Generic name: Levofloxacin
  • Brand names: Levaquin, Tavanic; Oftaquix, Quixin, Iquix
  • Dosages:
    Tablets 250 mg, 500 mg, 750 mg;
    Solution, oral 25 mg/mL;
    Injection (concentrate) 500 mg (25 mg/mL), 750 mg (25 mg/mL);
    Injection (premix) 250 mg (5 mg/mL), 500 mg (5 mg/mL), 750 mg (5 mg/mL).
  • Pharmacologic category: Fluoroquinolone antibiotic
  • FDA approved: December 20, 1996
  • Pregnancy risk factor: C

Medical uses

Levofloxacin is a powerful fluoroquinolone antibiotic with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and atypical pathogens.

Levofloxacin indicated uses include:

  • Respiratory Tract Infections: community-acquired pneumonia (CAP), hospital-acquired pneumonia, acute exacerbations of chronic bronchitis (AECB), acute sinusitis.
  • Genitourinary Tract infections: chronic bacterial prostatitis, uncomplicated UTI, acute pyelonephritis, complicated UTI
  • Complicated and uncomplicated skin and soft tissue infections

The most common levofloxacin side effects are nausea, diarrhea, headache, insomnia, and dizziness 4.

Pharmacological characteristics

  • Bioavailability: Nearly 100%
  • Absorption: Rapid and complete.
  • Metabolism: Undergoes limited hepatic metabolism.
  • Elimination half-life: 6 to 8 h
  • Excretion: 87% excreted as unchanged drug in urine, less than 4% in the feces.


  • Broad spectrum of antimicrobial activity
  • One of the safest new fluoroquinolones 4
  • Lss phototoxicity potential 3
  • Less CNS disturbances 3
  • Less cardiac effects 3
  • Not involved in major drug interactions (with warfarin, theophylline, or cyclosporin), compared to some of the other fluoroquinolones
  • Rapidly absorbed and extensively distributed into the tissues, the concentrations of levofloxacin are typically found to be higher in the tissues or body fluids than in plasma
  • Increased drug concentration - higher concentrations of levofloxacin also may help prevent the emergence of resistant organisms, a serious problem associated with fluoroquinolone use
  • Two mechanisms of action for bactericidal activity, one requiring RNA and protein synthesis, and another which does not
  • Excellent oral bioavailability, equivalent to intravenous
  • Highly active against Klebsiella species
  • Active against the organisms causing atypical pneumonias
  • May be useful in persons with liver disease in whom other fluoroquinolones may be contraindicated
  • Enhanced activity against gram-positive bacteria (including Streptococcus pneumoniae) compared with the older fluoroquinolones
  • Once-daily dose regimen


  • Tendon rupture, tendonitis and arthropathies (can occur during or after the treatment with levofloxacin). Factors that can increase the risk of tendon damage include concurrent use of corticosteroids, being older than 60 years.
  • Peripheral neuropathy (nerve damage) 7. The onset of peripheral nervous system side effects is rapid -- usually within 24-72 hours of initiating treatment.
  • Expensive

Unlabeled uses

  • Streptococcal pharyngitis 10 -- Levofloxacin is active against Group A streptococcus, but it has unnecessarily broad spectrum of activity and are therefore is not recommended for for routine treatment of strep throat.
  • Chronic periodontitis 9
  • Disseminated gonococcal infections
  • Typhoid fever 2
  • Chlamydial uro-genital infections 5
  • Legionnaires disease 6
  • Community-acquired pneumonia in children 7
  • Brucellosis 8

Mode of action

Levofloxacin is the L-isomer of the racemate, ofloxacin, a quinolone antibiotic. The antibacterial activity of ofloxacin resides primarily in the L-isomer. The mechanism of action of levofloxacin and other fluoroquinolone antimicrobials involves the inhibition of bacterial topoisomerase IV and DNA gyrase (both of which are Type II topoisomerases), enzymes required for DNA replication, transcription, repair, and recombination.

As the S (-) enantiomer of the fluoroquinolone, ofloxacin, levofloxacin, inhibits DNA-gyrase in susceptible organisms thereby inhibits relaxation of supercoiled DNA and promotes breakage of DNA strands. DNA gyrase (topoisomerase II), is an essential bacterial enzyme that maintains the superhelical structure of DNA and is required for DNA replication and transcription, DNA repair, recombination, and transposition.

Reviews & Discussions


  • Levaquin official website
  • 1. U.S. FDA. Levofloxacin (Levaquin) Prescribing Information
  • 2. Nelwan RH, Chen K, Nafrialdi, Paramita D. Open study on efficacy and safety of levofloxacin in treatment of uncomplicated typhoid fever. Southeast Asian J Trop Med Public Health. 2006 Jan;37(1):126-30.
  • 3. Yagawa K. Latest industry information on the safety profile of levofloxacin in Japan. Chemotherapy. 2001;47 Suppl 3:38-43; discussion 44-8.
  • 4. Kahn JB. The safety profile of levofloxacin in the US. Chemotherapy. 2001;47 Suppl 3:32-7; discussion 44-8.
  • 5. Mikamo H, Sato Y, Hayasaki Y, Hua YX, Tamaya T. Levofloxacin in the different treatment schedules of Chlamydia trachomatis uterine cervicitis. Chemotherapy. 2000 Mar-Apr;46(2):150-2.
  • 6. Yu VL, Greenberg RN, Zadeikis N, Stout JE, Khashab MM, Olson WH, Tennenberg AM. Levofloxacin efficacy in the treatment of community-acquired legionellosis. Chest. 2004 Jun;125(6):2135-9. PubMed
  • 7. Bradley JS, Arguedas A, Blumer JL, Sa'ez-Llorens X, Melkote R, Noel GJ. Comparative study of levofloxacin in the treatment of children with community-acquired pneumonia. Pediatr Infect Dis J. 2007 Oct;26(10):868-78. PubMed
  • 8. Kilic S, Dizbay M, Cabadak H. J Chemother. 2008 Feb;20(1):33-7.
  • 9. Pradeep AR, Singh SP, Martande SS, Naik SB, N P, Kalra N, Suke DK. Clinical and microbiological effects of levofloxacin in the treatment of chronic periodontitis: a randomized, placebo-controlled clinical trial. J Investig Clin Dent. 2014 Feb 27 PubMed
  • 10. Matsuzaki K, Yoshimori K, Shikano M, Watabe E, Sato Y, Hasegawa M, Kobayashi I, Yamanaka N. Susceptibility of major pathogens of acute pharyngitis and tonsillitis to levofloxacin and other oral antimicrobial drugs. Jpn J Antibiot. 2003 Jun;56(3):171-9. PubMed
  • 11. Cohen JS. Peripheral neuropathy associated with fluoroquinolones. Ann Pharmacother. 2001 Dec;35(12):1540-7. PubMed

Written by, October 2009
Last updated: June, 2015

Interesting facts

Levofloxacin 500 mg

  • In Europe, levofloxacin is marketed by Sanofi-Aventis under the trade name of Tavanic®, and in Asia it is marketed by Daiichi under the trade name of Cravit®.
  • As levofloxacin has a high oral bioavailability (about 99%) it is appropriate for intravenous-to-oral sequential treatment.
  • Chemically, levofloxacin is the S-enantiomer (L-isomer) of ofloxacin, and has approximately twice the potency of ofloxacin.

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