Fluoroquinolone antibiotic

Ciprofloxacin

Brand names: Ciproxin

Adult dose

Dose: PO 250–750mg BD; IV 400mg BD–TDS. UTI 250–500mg BD for 3 days. Bone/joint up to 750mg BD

Route: PO/IV

Frequency: BD

Paediatric dose

Dose: 15 mg/kg

Route: PO

Frequency: BD

Max: 750mg/dose

Restricted use in children — discuss with specialist; complicated UTI/pyelonephritis 10–20 mg/kg BD

Dose adjustments

Renal

CrCl 30–60: 250–500mg BD; CrCl <30: 250–500mg OD

Paediatric weight-based calculator

Patient weight (kg)

Restricted use in children — discuss with specialist; complicated UTI/pyelonephritis 10–20 mg/kg BD

Clinical pearls

MHRA: only use if other antibiotics inappropriate. Stop at first sign of tendinitis
Excellent oral bioavailability — IV-to-PO switch easy

Contraindications

History of tendon disorders with fluoroquinolones
Avoid in children/adolescents/pregnancy unless essential

Side effects

GI upset
Tendon rupture (esp. Achilles)
QT prolongation
C. difficile
CNS effects (confusion, seizures)
Aortic aneurysm/dissection
Disabling and potentially permanent musculoskeletal/CNS effects (MHRA warning)

Interactions

Antacids/iron/calcium/dairy reduce absorption (separate by 2h)
NSAIDs lower seizure threshold
Theophylline (raised levels)
Warfarin (raised INR)
QT-prolonging drugs

Monitoring

U&E
LFTs
ECG if QT risk

Reference: BNFc; BNF; MHRA Drug Safety Update; https://bnf.nice.org.uk/drugs/ciprofloxacin/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

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