Pharmacology · Other antibacterials
Chloramphenicol !
An old broad-spectrum antibiotic kept for serious infections when safer drugs fail, because it can destroy the bone marrow.
Updated 2026-11-01
The figure shows chloramphenicol bound at the peptidyl transferase centre of the Escherichia coli ribosome.
Mechanism of action
Chloramphenicol binds the 50S subunit at the peptidyl transferase centre and stops amino acids from being joined into the protein chain. It is mainly bacteriostatic, but bactericidal against some meningitis bacteria, and it reaches the cerebrospinal fluid well. Its toxicity to human bone marrow limits its use.
- Diffuses widely, including into the cerebrospinal fluid
- Binds the peptidyl transferase centre of the 50S subunit
- Peptide bonds are not formed
- Bacterial growth stops
Pharmacokinetics
- Absorption
- Given IV as the succinate, a prodrug; it is ineffective by intramuscular injection.
- Distribution
- Wide, with good cerebrospinal fluid levels.
- Metabolism
- Liver (glucuronidation); newborns clear it poorly.
Indications
- Bacterial meningitis when first-line drugs are unavailable or contraindicated (WHO second choice) Bacterial meningitis →
- Typhoid fever (Salmonella Typhi) when safer drugs cannot be used
- Other serious infections in which less dangerous antibiotics are ineffective or contraindicated
Adverse effects
Common
- Nausea, vomiting and diarrhoea
- Headache, low mood and confusion
- Rash
Contraindications
- Previous allergy or toxic reaction to chloramphenicol
- Not used for minor infections or prophylaxis
Key interactions
- Other bone-marrow-suppressing drugs
- Avoided together because marrow toxicity adds up.
What is monitored
- Full blood count before and frequently during treatment
- Serum levels in newborns and in liver disease
- Vision and sensation with long courses
Administration and safety
- IV only; it does not work by intramuscular injection
- Given slowly IV over at least a minute after reconstitution
- Changed to a safer drug as soon as culture results allow
Nursing care
- Check blood counts as ordered and report falls
- Teach to report sore throat, fever, bruising or unusual tiredness
- In newborns, watch for abdominal swelling, grey skin and poor circulation
- Ask about blurred vision or tingling in long courses
Pregnancy and breastfeeding
Given in pregnancy only if the benefit justifies the risk; use near labour has been linked with grey syndrome in the newborn.
Test yourself
Think of the answer, then tap the question to see it.
What is the boxed warning of chloramphenicol?
Serious and fatal blood dyscrasias, including irreversible aplastic anaemia.
Why is chloramphenicol dangerous in newborns?
They clear it poorly and it builds up, causing grey syndrome (distension, cyanosis and circulatory collapse).
Why does chloramphenicol still have a role in meningitis?
It reaches the cerebrospinal fluid well and is a WHO second choice where first-line drugs are not available.
Related drugs
Related conditions
← Back to the class: Other antibacterials
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - CHLORAMPHENICOL SODIUM SUCCINATE- chloramphenicol sodium succinate injection, powder, lyophilized, for solution (DailyMed (U.S. National Library of Medicine), 2026); Chloramphenicol Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.