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Fluoroquinolone Antibiotic Pregnancy: Available data indicate no malformative or feto/neonatal toxicity, but as a precautionary measure it is preferable to avoid use during pregnancy (possible effect on immature articular cartilage). Should not be used during breast-feeding due to potential risk of articular damage.

Ciprofloxacin

Brand names: Ciproxin

Ciprofloxacin is a fluoroquinolone antibiotic with broad Gram-negative activity, used for urinary, respiratory, gastrointestinal and certain other infections including those caused by Pseudomonas.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 500 mg to 750 mg twice daily (indication-dependent). Uncomplicated cystitis: 250 mg to 500 mg twice daily for 3 days. Complicated cystitis / uncomplicated pyelonephritis: 500 mg twice daily for 7 days
Route: Oral
Frequency: Twice daily (usually every 12 hours)
Max: 750 mg twice daily (per adult posology table)
General-medicine (systemic oral tablet) context. Dose depends on indication, severity, site of infection, causative organism susceptibility, and renal function. Lower/upper respiratory tract, sinusitis, chronic suppurative otitis media, skin/soft tissue, bone and joint, intra-abdominal (Gram-negative), neutropenic fever: 500 mg to 750 mg twice daily. Malignant external otitis: 750 mg twice daily for 28 days up to 3 months. Complicated pyelonephritis / prostatitis: 500 mg to 750 mg twice daily. Gonococcal urethritis/cervicitis and meningococcal prophylaxis: 500 mg as a single dose. Typhoid fever: 500 mg twice daily for 7 days. Inhalation anthrax post-exposure prophylaxis/treatment: 500 mg twice daily for 60 days. Ciprofloxacin monotherapy is not suitable for severe or Gram-positive/anaerobic infections (co-administer other antibacterials) and is not recommended for streptococcal infections. Do not take with dairy products or mineral-fortified juice. Duration depends on severity and clinical/bacteriological course.

Paediatric dose

Dose: 20 mg/kg
Route: Oral
Frequency: Twice daily
Max: 750 mg per dose
Cystic fibrosis: 20 mg/kg twice daily (max 750 mg/dose) for 10-14 days. Complicated UTI and pyelonephritis: 10 to 20 mg/kg twice daily (max 750 mg/dose) for 10-21 days. Inhalation anthrax post-exposure prophylaxis/treatment: 10 to 15 mg/kg twice daily (max 500 mg/dose) for 60 days. Other severe infections: 20 mg/kg twice daily (max 750 mg/dose). Dosing in children with renal/hepatic impairment has not been studied. Verify paediatric dosing against a current children's formulary.

Dose adjustments

Renal

CrCl 30-60 mL/min/1.73m2: 250-500 mg every 12 h. CrCl <30 mL/min/1.73m2: 250-500 mg every 24 h. Haemodialysis: 250-500 mg every 24 h (after dialysis). Peritoneal dialysis: 250-500 mg every 24 h. No dose adjustment needed in hepatic impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Cystic fibrosis: 20 mg/kg twice daily (max 750 mg/dose) for 10-14 days. Complicated UTI and pyelonephritis: 10 to 20 mg/kg twice daily (max 750 mg/dose) for 10-21 days. Inhalation anthrax post-exposure prophylaxis/treatment: 10 to 15 mg/kg twice daily (max 500 mg/dose) for 60 days. Other severe infections: 20 mg/kg twice daily (max 750 mg/dose). Dosing in children with renal/hepatic impairment has not been studied. Verify paediatric dosing against a current children's formulary.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to ciprofloxacin, other quinolones, or any excipient
  • Concomitant administration with tizanidine

Side effects

  • Nausea (most common)
  • Diarrhoea (most common)
  • Vomiting
  • Gastrointestinal and abdominal pain
  • Headache, dizziness

Interactions

  • Tizanidine (contraindicated)
  • Dairy products and mineral-fortified juice reduce absorption (avoid taking together)

Clinical monograph

How it works

It inhibits bacterial DNA gyrase (topoisomerase II) and topoisomerase IV, preventing DNA replication and leading to bacterial cell death.

Prescribing in practice

  • MHRA warns of disabling and potentially irreversible tendon, musculoskeletal and neuropsychiatric reactions; stop at the first sign of tendon pain or inflammation and avoid in patients at high risk.
  • It prolongs the QT interval and can cause aortic aneurysm/dissection, so use caution with other QT-prolonging drugs and in those with aneurysm risk factors.
  • Ciprofloxacin inhibits CYP1A2 and markedly raises theophylline and tizanidine levels; it also potentiates warfarin and chelates with calcium, antacids and iron.

Monitoring

Monitor for tendon, neurological and psychiatric symptoms throughout treatment, and review interacting drugs such as theophylline and warfarin.

Counselling the patient

  • Stop and seek advice immediately if you develop tendon pain or swelling.
  • Avoid taking it at the same time as dairy products, antacids or iron, which block absorption.
  • Report new numbness, tingling, mood changes or palpitations.

Evidence & guidelines

The MHRA has issued repeated safety warnings (2019 and 2023) restricting fluoroquinolone use because of the risk of long-lasting and disabling adverse effects.

Reference: MHRA Quinolone Safety Update 2018/2019; NICE NG112 (UTI in Adults); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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