Ciprofloxacin
Tablet, injection or eye drops
Quick Summary
Ciprofloxacin kills a wide range of bacteria, but because of rare serious side effects it's reserved for specific infections.
Medical Uses
How it's taken
Drink plenty of fluids. Don't take it at the same time as dairy, antacids, iron or calcium.
Take it for the full course, even if you feel better, unless your doctor tells you otherwise. Don't share antibiotics or keep leftovers.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Nausea
And diarrhoea.
Dizziness
Headache or restlessness.
Tendon pain
Stop and see a doctor.
Interactions
Antacids, iron, calcium
Reduce absorption; separate doses.
Theophylline
Levels rise.
Warfarin
Bleeding risk.
Critical Warnings
Tendon damage
Black Box Warning: Can cause tendon inflammation or rupture, especially in older people or with steroids.
Nerve and mental effects
Tingling, confusion or mood changes: stop and seek advice.
Severe allergic reaction
Black Box Warning: Swelling of the face or throat, difficulty breathing or a widespread rash: get emergency help.
Antibiotic resistance
Using antibiotics when they aren't needed makes them less effective for everyone.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Ciprofloxacin: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Ciprofloxacin: medicine for serious infections.(opens in a new tab) · NHS