Chloramphenicol

Key facts

• Chloramphenicol is a broad-spectrum antibiotic that stops bacteria producing the proteins they need to survive; it's available as eye drops or ointment, and, for serious infections, as tablets or injection.
• Eye drops treat bacterial conjunctivitis; oral or injected chloramphenicol is reserved for serious infections such as typhoid fever or meningitis that haven't responded to safer antibiotics.
• Systemic chloramphenicol carries a rare, unpredictable risk of aplastic anaemia, bone marrow failure that stops the body producing blood cells and can be fatal; regular blood counts are required during treatment.
• Seek urgent care for unusual bruising or bleeding, a persistent sore throat and fever, or extreme tiredness.

What Chloramphenicol treats

Chloramphenicol treats bacterial conjunctivitis and other eye infections as drops or ointment, and, given as tablets or injection, serious infections such as typhoid fever, bacterial meningitis, and infections from bacteria resistant to safer antibiotics. Oral and injectable use is limited to situations where alternatives aren't suitable, given the blood-count risks.

How Chloramphenicol works

Chloramphenicol binds to the bacterial ribosome and blocks it from assembling proteins, stopping bacteria growing and multiplying. Human cells have differently structured ribosomes for most purposes, but chloramphenicol can still affect the bone marrow, which is why blood monitoring matters during systemic treatment.

Before you take it

• Do not use systemic chloramphenicol if you've previously had a blood disorder from this drug; it should only be used when the infection genuinely needs it.
• Tell your prescriber about liver or kidney disease, and about any other medicines that affect blood cells, including certain HIV and cancer treatments.
• Chloramphenicol is avoided in newborns unless essential and given only under specialist supervision; an immature liver can't clear it properly, causing "grey baby syndrome," a dangerous drop in blood pressure and circulation.
• Regular blood counts are needed before and during a course of oral or injected chloramphenicol.

Side effects

With eye drops, mild stinging and blurred vision are common. With systemic use, nausea and headache can occur.

Stop and seek urgent medical care for any of these:

• Unusual bruising, bleeding gums, or blood in urine or stool.
• Persistent sore throat, fever, mouth ulcers, or infections that won't clear.
• Extreme tiredness or paleness.
• Grey-blue skin colour, low body temperature or limpness in a newborn.

Safety essentials

• Systemic chloramphenicol carries a rare but potentially fatal risk of aplastic anaemia; it's reserved for serious infections where the benefit outweighs this risk, and regular blood tests are mandatory throughout treatment.
• Report any unusual bruising, bleeding, sore throat or fever straightaway, these can be early signs of bone marrow suppression.
• Only use chloramphenicol eye drops or tablets prescribed for you, and finish the full course, stopping early leaves infection to return and adds to antibiotic resistance.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.