[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Fluoroquinolones](https://durgical.com/en/pharmacology/classes/fluoroquinolones/) › Levofloxacin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Fluoroquinolones](https://durgical.com/en/pharmacology/classes/fluoroquinolones/)

# Levofloxacin

A «respiratory» fluoroquinolone that covers pneumococcus and atypical bacteria, fully absorbed by mouth and also used for drug-resistant tuberculosis.

Updated 2026-11-01

- Class: [Fluoroquinolones](https://durgical.com/en/pharmacology/classes/fluoroquinolones/)
- Enzyme: Bacterial topoisomerase IV and DNA gyrase
- ATC code: J01MA12
- WHO Model List of Essential Medicines

✂**Bacterial topoisomerase IV and DNA gyrase**Levofloxacin

ⓘ The figure shows levofloxacin bound to DNA cut by topoisomerase IV of Streptococcus pneumoniae.

**Target in 3D:** Bacterial topoisomerase IV and DNA gyrase. PDB structure 3RAE (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/3RAE) · Drag to rotate · pinch to zoom

## Mechanism of action

Levofloxacin, the active S-isomer of ofloxacin, traps topoisomerase IV and DNA gyrase on DNA they have cut. In pneumococcus topoisomerase IV is its main target. The trapped complexes turn into double-strand breaks and the bacterium dies.

- Absorbed almost completely by mouth
- Binds topoisomerase IV or gyrase on cut DNA
- The enzyme cannot reseal the DNA
- Double-strand breaks kill the bacterium

## Pharmacokinetics

**Absorption**
Oral bioavailability about 99%; oral and IV forms give similar levels.

**Metabolism**
Very little.

**Elimination**
Mostly unchanged in the urine; the dose is adjusted when kidney function is reduced.

**Half-life**
About 6–8 hours.

## Indications

- Community-acquired pneumonia, including atypical bacteria and penicillin-resistant pneumococcus [Community-acquired pneumonia →](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- Acute pyelonephritis and complicated urinary tract infection [Acute pyelonephritis →](https://durgical.com/en/conditions/acute-pyelonephritis/)
- Chronic bacterial prostatitis [Prostatitis →](https://durgical.com/en/conditions/prostatitis/)
- Drug-resistant tuberculosis (WHO list of antituberculosis medicines) [Tuberculosis →](https://durgical.com/en/conditions/tuberculosis/)
- Inhalational anthrax after exposure and plague

## Adverse effects

### Common

- Nausea, diarrhoea and headache
- Insomnia and dizziness
- Photosensitivity

### Serious (rare, important)

- Tendinitis and tendon rupture, peripheral neuropathy and CNS effects (boxed warning)
- Worse myasthenia gravis
- Severe hypoglycaemia (coma and deaths reported) or hyperglycaemia, especially with antidiabetic drugs
- QT prolongation, aortic aneurysm and dissection, hepatotoxicity and C. difficile colitis

## Contraindications

- Allergy to levofloxacin or other quinolones

## Key interactions

**Antacids, sucralfate, iron, zinc and other polyvalent cations**
Reduce absorption; the doses are spaced.

**Insulin and oral antidiabetic drugs**
Risk of severe low or high blood sugar.

**Warfarin**
Stronger anticoagulant effect.

**Corticosteroids**
Higher risk of tendon rupture.

## What is monitored

- Blood glucose, especially in diabetes
- Kidney function to adjust the dose
- Tendon pain, neuropathy symptoms and mental changes; ECG if QT risk

## Administration and safety

- Oral doses are spaced from antacids and mineral supplements
- The IV form is infused slowly, never as a rapid or intramuscular injection
- Oral and IV forms are interchangeable at the same dose

## Nursing care

- Teach the signs of hypoglycaemia
- Teach to stop and report tendon pain or tingling
- Encourage fluids
- Ask about myasthenia gravis and steroid use

## Pregnancy and breastfeeding

Usually avoided when a safer alternative exists; human data are limited.

## Memory aid

«Levo levels the lungs»: the left-handed (levo) half of ofloxacin, made for chest infections.

## Test yourself

Think of the answer, then tap the question to see it.

## How does levofloxacin relate to ofloxacin?

It is the active S-isomer (levo form) of ofloxacin.

## Why can a patient switch from IV to oral levofloxacin at the same dose?

Oral bioavailability is close to 100%.

## Which metabolic adverse effect must diabetic patients watch for?

Severe hypoglycaemia (or hyperglycaemia).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/levofloxacin/)

## Related drugs

- [Ciprofloxacin](https://durgical.com/en/pharmacology/ciprofloxacin/)
- [Moxifloxacin](https://durgical.com/en/pharmacology/moxifloxacin/)
- [Ofloxacin](https://durgical.com/en/pharmacology/ofloxacin/)

## Related conditions

- [Community-acquired pneumonia](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- [Acute pyelonephritis](https://durgical.com/en/conditions/acute-pyelonephritis/)
- [Prostatitis](https://durgical.com/en/conditions/prostatitis/)
- [Tuberculosis](https://durgical.com/en/conditions/tuberculosis/)

[← Back to the class: Fluoroquinolones](https://durgical.com/en/pharmacology/classes/fluoroquinolones/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - LEVOFLOXACIN tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d98cf024-51fa-45a1-b247-da55aba88ca0) (DailyMed (U.S. National Library of Medicine), 2026); [Levofloxacin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a697040.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=levofloxacin) (World Health Organization, 2025); [Quinolone(Levofloxacin)-DNA cleavage complex of type IV topoisomerase from S. pneumoniae](https://www.rcsb.org/structure/3RAE) (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/levofloxacin/