Levofloxacin

How it works

It inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, blocking DNA replication and transcription, producing a bactericidal effect.

Prescribing in practice

• MHRA warns of disabling and potentially long-lasting or irreversible musculoskeletal and nervous system effects, including tendon rupture and aortic aneurysm or dissection, so reserve fluoroquinolones and stop at the first sign of tendon pain.
• It can prolong the QT interval, so use caution with other QT-prolonging drugs and in electrolyte disturbance.
• Absorption is reduced by calcium, iron, zinc and antacids, and it lowers the seizure threshold.

Monitoring

There is no routine laboratory monitoring, but observe for tendon, neurological and cardiac adverse effects and stop promptly if they occur.

Counselling the patient

• Stop and seek advice if you develop tendon pain or swelling, new numbness or tingling, or significant mood changes.
• Separate from indigestion remedies and iron or calcium supplements, and avoid excessive sun exposure.
• Report palpitations or fainting.

Evidence & guidelines

MHRA fluoroquinolone safety reviews restrict levofloxacin to situations where other antibiotics cannot be used, reflected in NICE antimicrobial prescribing guidance.