FFinalistSouthampton · 2027
The drug atlas
Antimicrobials/Fluoroquinolone

Fluoroquinolones

also: ciprofloxacin · levofloxacin · ofloxacin · quinolone

Overview

Broad oral Gram-negative/atypical cover — but MHRA-restricted because of disabling, sometimes irreversible adverse effects.

Mechanism

Inhibit DNA gyrase / topoisomerase IV → prevent bacterial DNA replication (bactericidal).

The agents

CiprofloxacinGram−/Pseudomonas

oral/IV

Complicated UTI/pyelonephritis, prostatitis, travellers' diarrhoea, malignant otitis externa.

Levofloxacinrespiratory quinolone

CAP in penicillin allergy (atypical cover).

Adverse effects

Tendon rupture (esp. Achilles; worse with steroids)serious
QT prolongation; aortic aneurysm/dissection riskserious
Lowers seizure threshold; neuropsychiatric effectscommon
C. difficile (high risk)serious

Cautions & contraindications

MHRA restriction: avoid for non-severe/self-limiting infectionsall

Disabling, potentially irreversible tendon/MSK/neuro effects.

Pregnancy / childrenpregnancy

Cartilage damage.

Epilepsy, myasthenia gravis, prior tendon disorderall

Interactions

  • Absorption ↓ by calcium/iron/antacids; raises theophylline; QT drugs; warfarin

Monitoring & kinetics

Tendon/neuro symptoms (stop if they occur)

Oral (excellent bioavailability) / IV.

Choosing it

Spectrum: Gram-negatives incl. Pseudomonas (ciprofloxacin), atypicals; levofloxacin adds Gram-positive/Strep pneumoniae. Poor anaerobe cover.

Source: BNF — Quinolones · MHRA — Fluoroquinolone restriction