Ciprofloxacin (Orthopaedic — Gram-negative Osteomyelitis)

How it works

Ciprofloxacin is a fluoroquinolone that inhibits bacterial DNA gyrase and topoisomerase IV, blocking DNA replication and producing bactericidal killing of many Gram-negative organisms.

Prescribing in practice

• MHRA warns of rare but serious, sometimes irreversible, disabling musculoskeletal and neurological adverse effects including tendinitis and tendon rupture (especially Achilles, higher risk with corticosteroids and in older patients) — stop at the first sign of tendon pain and avoid in those with prior fluoroquinolone tendon injury.
• It prolongs the QT interval and lowers the seizure threshold, so review concurrent QT-prolonging drugs and use caution in epilepsy; it also interacts strongly with theophylline and with divalent/trivalent cations that impair absorption.
• Confirm susceptibility before relying on it for bone infection, separate doses from antacids, dairy and iron/calcium, and adjust frequency in renal impairment per the SPC.

Monitoring

Monitor clinical and biochemical response of the bone infection, and remain alert for tendon, neurological, QT and glycaemic adverse effects throughout the prolonged course.

Counselling the patient

• Stop the drug and seek advice at once if you develop tendon, joint or muscle pain or swelling, or new numbness or tingling.
• Do not take it at the same time as indigestion remedies, dairy products or iron/calcium supplements.
• Avoid excessive sun exposure as the skin can become more sensitive to light.

Evidence & guidelines

MHRA Drug Safety Updates restrict systemic fluoroquinolones to situations where other antibiotics are unsuitable because of the risk of long-lasting and disabling adverse effects.