What is levofloxacin? How does it work (mechanism of action)?

Levofloxacin is an antibiotic that is used for treating bacterial infections.

Many common infections in humans are caused by bacteria. Bacteria can grow and multiply, infecting different parts of the body. Drugs that control and eradicate these bacteria are called antibiotics. Levofloxacin is an antibiotic that stops multiplication of bacteria by preventing the reproduction and repair of their genetic material, DNA. It is in a class of antibiotics called fluoroquinolones, a class that includes:

The FDA approved levofloxacin in December 1996.

What are the uses for levofloxacin?

  • Levofloxacin is used to treat infections of the sinuses, skin, lungs, ears, airways, bones, and joints caused by susceptible bacteria.
  • Levofloxacin is frequently used to treat urinary infections, including those resistant to other antibiotics, as well as prostatitis (infection of the prostate).
  • Levofloxacin is effective in treating infectious diarrhea caused by E. coli, Campylobacter jejuni, and Shigella bacteria.
  • Levofloxacin can be used to treat various obstetric infections, including mastitis (infection of the breast).
  • Inhalational anthrax exposure also is treated with levofloxacin.
  • Levofloxacin is used for preventing and treating plague caused by Yersinia pestis.

What are the side effects of levofloxacin?

Serious side effects and warnings include:

  • Levofloxacin as well as other antibiotics in the fluoroquinolone class of antibiotics have been associated with tendinitis and even rupture of tendons, particularly the Achilles tendon.
  • Fluoroquinolones have neuromuscular blocking activity and can worsen muscle weakness in individuals with myasthenia gravis.

The most frequently reported side effects are:

Less common side effects include:

Rare allergic reactions have been described are:


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What are the serious side effects (adverse effects) of levofloxacin

Possible serious side effects of levofloxacin include:

Other serious side effects and adverse events of levofloxacin include:

  • Levofloxacin should be used with caution in patients with central nervous system diseases such as seizures, because rare seizures have been reported in patients receiving Levaquin.
  • Levofloxacin should be avoided in children and adolescents less than 18 years of age, as safe use in these patients has not been established.
  • Many antibiotics, including levofloxacin, can alter the normal bacteria in the colon and encourage overgrowth of a bacterium responsible for the development of inflammation of the colon, (C. difficile or pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting Levaquin (diarrhea, fever, abdominal pain, and possibly shock) should contact their doctor immediately.
  • Patients taking Levofloxacin can develop sensitivity of the skin to direct sunlight (photosensitivity) and should avoid exposure to sunlight or use sunblock.
  • Fluoroquinolones worsen low blood glucose levels when combined with sulfonylureas (for example, glyburide [Micronase, Diabeta, Glynase, Prestab]).
  • Because of serious side effects associate with fluoroquinolones, they should not be used for treating uncomplicated urinary tract infections, acute bacterial exacerbation of chronic bronchitis or acute bacterial sinusitis unless there are no other alternatives.

What is the dosage for levofloxacin? How is it taken?

  • The usual dose is 250-750 mg given once daily for 3-14 days depending on the type of infection.
  • Anthrax is treated with 500 mg daily for 60 days.
  • It is important to take oral formulations at least 2 hours before or 2 hours after any antacid or mineral supplement containing iron, calcium, zinc, or magnesium since these bind Levaquin and prevent its absorption into the body.

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Which drugs or supplements interact with levofloxacin?

  • Iron, calcium, zinc, or magnesium can attach to levofloxacin and other fluoroquinolones and prevent their absorption from the intestine into the blood. Therefore, products (for example, antacids) that contain iron, calcium, zinc, or magnesium should be taken at least 2 hours before or 2 hours after levofloxacin. Other drugs that contain these minerals and can similarly interact with levofloxacin include sucralfate (Carafate) and didanosine (Videx, Videx EC).
  • Taking nonsteroidal anti-inflammatory drugs (NSAIDs) with levofloxacin may increase the risk of central nervous stimulation, resulting in over-excitation. There have been reports of changes in blood sugar (increases and decreases) in patients treated with fluoroquinolones and antidiabetic agents.
  • Fluoroquinolones may increase the effect of warfarin (Coumadin, Jantoven).

Is levofloxacin safe to take if I’m pregnant or breastfeeding?

  • Levaquin is not recommended for use in pregnant women since Levaquin causes joint and bone deformities in juvenile animals of several species.
  • Levaquin is excreted in breast milk. Mothers should decide whether to stop breastfeeding or discontinue Levaquin.

What else should I know about levofloxacin?

  • Levofloxacin is available in generic form. you need a prescription from a doctor or pharmacist to obtain this antibiotic. The brand name for levofloxacin, Leviquin, has been discontinued.
  • Preparations for levofloxacin are:
    • Tablets: 250, 500 and 750 mg
    • Oral solution: 25 mg/mL
    • Injection: 500 mg/20 ml and 750 mg/30 ml
    • Premix ready to use injection: 250 mg/50 ml, 500 mg/100 ml, and 750 mg/150 mll
    • Levofloxacin should be stored at 15 C to 30 C (59 F to 86 F)


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Medically Reviewed on 11/25/2019


FDA Prescribing Information