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 antibacterial with broad Gram-negative activity, used for urinary, respiratory, gastrointestinal, bone and joint infections and as one of few oral agents active against 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)

Oral tablet (systemic) posology. Dose depends on indication, severity, site of infection, causative organism susceptibility, and renal function. Lower/upper respiratory tract, acute exacerbation of chronic 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 prophylaxis of invasive meningococcal infection: 500 mg as a single dose. Diarrhoea (bacterial pathogens/travellers'): 500 mg twice daily for 1 day; Shigella dysenteriae type 1: 5 days; Vibrio cholerae: 3 days; typhoid fever: 7 days. Inhalation anthrax post-exposure prophylaxis/treatment: 500 mg twice daily for 60 days. Not suitable as monotherapy for severe or Gram-positive/anaerobic infections (co-administer other antibacterials); 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

Patient weight (kg)

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 and topoisomerase IV, preventing DNA supercoiling and replication, giving a bactericidal effect.

Prescribing in practice

MHRA warns of rare but disabling and potentially irreversible tendon, musculoskeletal and neuropsychiatric adverse effects; stop at the first sign of tendon pain and avoid in patients at higher risk where alternatives exist.
Prolongs the QT interval and chelates with divalent/trivalent cations, so separate from antacids, calcium, iron and dairy and review concomitant QT-prolonging drugs.
A potent CYP1A2 inhibitor that raises theophylline and tizanidine levels and potentiates warfarin, and it lowers the seizure threshold.

Monitoring

Monitor for tendon, neurological and psychiatric symptoms, and check INR in patients taking warfarin.

Counselling the patient

Stop the medicine and seek advice if you develop tendon pain or swelling, new numbness, or mood changes.
Take iron, calcium, indigestion remedies and dairy products well apart from your doses.
Avoid excessive sun exposure as the skin can become more sensitive.

Evidence & guidelines

MHRA Drug Safety Updates on fluoroquinolones reinforce restricted use and the tendon and systemic safety warnings.

Reference: MHRA Drug Safety Update; 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Pathways