Levofloxacin

A potent fluoroquinolone antibiotic used for serious bacterial infections.

What is Levofloxacin?

Levofloxacin is a third-generation fluoroquinolone antibiotic and the active L-isomer of ofloxacin.

It offers stronger and more targeted antibacterial activity.

History & Background

Levofloxacin was developed to improve the effectiveness and safety profile of earlier fluoroquinolones by isolating the active enantiomer.

Chemical Structure & Properties

• IUPAC name: (S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid
• Molecular formula: C₁₈H₂₀FN₃O₄
• Molar mass: 361.37 g/mol
• Functional groups: Fluoroquinolone core, carboxylic acid

Mechanism of Action

Levofloxacin kills bacteria by:

• Inhibiting DNA gyrase
• Blocking topoisomerase IV
• Preventing bacterial DNA replication

Pharmacokinetics

• Absorption: Excellent oral absorption (~99%)
• Peak plasma time: 1–2 hours
• Half-life: 6–8 hours
• Metabolism: Minimal
• Excretion: Urine (unchanged)

Medical Uses

• Community-acquired pneumonia
• Urinary tract infections
• Skin and soft tissue infections
• Sinusitis
• Prostatitis

Dosage Guidelines

Adults: 250–750 mg once daily

Duration: Depends on infection type

⚠️ Avoid unnecessary use to prevent resistance.

Side Effects

• Nausea
• Dizziness
• Headache
• Tendon pain or rupture

Warnings & Precautions

• Risk of tendon rupture (elderly)
• Avoid in pregnancy unless essential
• QT prolongation risk

Drug Interactions

• Antacids and iron supplements
• Antiarrhythmic drugs
• Corticosteroids (↑ tendon risk)

Frequently Asked Questions

Is levofloxacin stronger than ofloxacin? – Yes.

Can it treat viral infections? – No.

Is it safe long-term? – Short-term use preferred.

Why is it restricted? – Safety concerns.

⚠️ Educational content only. Not a substitute for professional medical advice.