- Levofloxacin is a widely used fluoroquinolone antibiotic known for its broad-spectrum activity against both Gram-positive and Gram-negative bacteria.
- It is commonly prescribed for respiratory, urinary tract, and skin infections due to its strong bactericidal effects.
- As a third-generation fluoroquinolone, levofloxacin exhibits improved efficacy and lower resistance rates compared to earlier fluoroquinolones, making it a valuable option in modern antimicrobial therapy.
- Levofloxacin is the levo-rotatory isomer of ofloxacin, enhancing its biological activity and reducing potential side effects. Its core structure consists of a quinolone scaffold with a fluorine atom at the C-6 position, facilitating better bacterial penetration and enzyme inhibition.
- Levofloxacin is available in various formulations, including oral tablets, intravenous solutions, and ophthalmic preparations, providing flexibility in treatment approaches depending on the severity of infection.
- Levofloxacin targets bacterial DNA replication by inhibiting DNA gyrase (in Gram-negative bacteria) and topoisomerase IV (in Gram-positive bacteria). These enzymes are essential for DNA supercoiling, chromosome segregation, and cellular survival.
- By stabilizing the DNA-enzyme complex in a cleaved state, levofloxacin prevents DNA strand re-ligation, resulting in lethal double-strand breaks. This mechanism ensures bactericidal action, making levofloxacin particularly effective against bacteria such as Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa.
- Levofloxacin is commonly prescribed for treating:
- Respiratory tract infections – including pneumonia, sinusitis, and chronic bronchitis exacerbations.
- Urinary tract infections – such as pyelonephritis and complicated cystitis.
- Soft tissue infections – including cellulitis and wound infections.
- Prostatitis – effectively treats bacterial infections of the prostate.
- Anthrax exposure – approved for post-exposure prophylaxis in inhalational anthrax cases.
- Despite its effectiveness, levofloxacin has potential side effects, including tendon rupture, QT interval prolongation, and central nervous system effects such as dizziness and confusion. Its use is carefully regulated, particularly in elderly patients and those with predisposing conditions.
- Resistance to levofloxacin has emerged due to mutations in DNA gyrase and topoisomerase IV, as well as efflux pump activation. Overuse of fluoroquinolones in both human and veterinary medicine has contributed to rising resistance rates, prompting guidelines to restrict their use when alternative antibiotics are available.
- Future research focuses on modifying fluoroquinolone structures to overcome resistance while maintaining antimicrobial efficacy. As bacterial resistance continues to evolve, levofloxacin remains a valuable but carefully monitored component of antibiotic therapy.
