Levofloxacin Istituto Biochimico Italiano G. Lorenzini (Levofloxacin)

Levofloxacin is a broad‑spectrum fluoroquinolone used to treat infections caused by susceptible bacteria.

• Community‑Acquired Pneumonia: achieves clinical cure and bacterial eradication.
• Acute Uncomplicated Urinary Tract Infection: resolves symptoms and clears the pathogen.
• Skin and Soft‑Tissue Infections: promotes healing by eliminating causative organisms.
• Acute Bacterial Sinusitis: reduces inflammation and clears infection.
• Chronic Bronchitis Exacerbation: improves respiratory function and prevents progression.

• Levofloxacin inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, enzymes essential for DNA replication, transcription, and repair. By stabilizing the enzyme‑DNA complex, it prevents the resealing of DNA strands, leading to bacterial cell death and a bactericidal effect against a wide range of Gram‑positive and Gram‑negative organisms.

Levofloxacin may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Diarrhea: loose stools, sometimes watery.
• Headache: transient cranial discomfort.
• Dizziness: sensation of light‑headedness.
• Rash: mild skin erythema or itching.
• Elevated liver enzymes: transient increase in hepatic markers.

Serious or Rare Side Effects

• Tendon rupture: especially Achilles tendon, may occur without warning.
• QT interval prolongation: risk of cardiac arrhythmias.
• Severe allergic reactions: anaphylaxis, angioedema, or Stevens‑Johnson syndrome.
• Clostridioides difficile infection: colitis due to gut flora disruption.
• Peripheral neuropathy: numbness or tingling in extremities.
• Seizures: lowered seizure threshold in predisposed patients.

Levofloxacin requires careful assessment of patient risk factors before use.

• Renal function: adjust dose in patients with impaired clearance.
• Hepatic disease: monitor liver function tests during therapy.
• Cardiac risk: avoid in patients with known QT prolongation or arrhythmias.
• Concomitant corticosteroids: increase vigilance for tendon injury.
• Pregnancy and lactation: use only if benefits outweigh potential risks, as safety data are limited.
• Store at ambient temperature: keep in original container, protect from light and moisture.

Levofloxacin can alter the pharmacokinetics of several drugs, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Antacids containing magnesium or aluminum: markedly reduce levofloxacin absorption.
• Warfarin: potentiate anticoagulant effect, increasing bleeding risk.
• Cyclosporine: heightened risk of tendon toxicity and nephrotoxicity.

Moderate Interactions (Monitor Closely)

• Systemic corticosteroids: monitor for signs of tendon rupture.
• Diabetes medications (e.g., insulin, sulfonylureas): may affect glucose control.
• Theophylline: levofloxacin can increase serum theophylline concentrations, risking toxicity.