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Antibiotic — broad-spectrum Pregnancy: Contraindicated in pregnancy and whilst breastfeeding (UK SPC).

Chloramphenicol

Brand names: Chloromycetin, Optrex Infected Eyes

Chloramphenicol is a broad-spectrum antibacterial used topically for bacterial eye infections such as conjunctivitis and, systemically, reserved for serious infections such as certain forms of meningitis where alternatives are unsuitable.

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: 1 g (equivalent of chloramphenicol)
Route: intravenous injection or infusion, or intramuscular injection
Frequency: every 6-8 hours
Dose and concentration depend on severity of infection. Adults: equivalent of 1 g every 6-8 hours. Elderly: usual adult dosage subject to normal hepatic and renal function. In exceptional cases (septicaemia or meningitis) schedules up to 100 mg/kg/day may be prescribed but should be decreased as soon as clinically indicated. Continue treatment after temperature returns to normal for 4 days in rickettsial diseases and 8-10 days in typhoid fever. Best given IV (10% / 100 mg/mL solution over at least 1 minute, or by slow infusion); IM absorption slow and unpredictable. Reserve for serious infections where less toxic antibiotics are ineffective or contraindicated; monitor serum levels and haematology.

Paediatric dose

Dose: 50 mg/kg
Route: intravenous injection or infusion, or intramuscular injection
Frequency: daily in divided doses every 6 hours
Max: 50 mg/kg/day (this dose should not be exceeded; up to 100 mg/kg/day only in exceptional cases such as septicaemia or meningitis, decreased as soon as clinically indicated)
Children: equivalent of 50 mg/kg chloramphenicol per day in divided doses every 6 hours; observe carefully for signs of toxicity. Neonates and premature infants: total 25 mg/kg/day in 4 equal doses at 6-hour intervals; risk of neonatal Grey syndrome. Verify against a children's formulary.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Children: equivalent of 50 mg/kg chloramphenicol per day in divided doses every 6 hours; observe carefully for signs of toxicity. Neonates and premature infants: total 25 mg/kg/day in 4 equal doses at 6-hour intervals; risk of neonatal Grey syndrome. Verify against a children's formulary.

Verify in a children's formulary

Contraindications

  • Previous history of sensitivity and/or toxic reaction to chloramphenicol
  • Pregnancy and breast-feeding
  • Trivial infections, or where not indicated (e.g. colds, influenza, throat infections), or as prophylaxis

Side effects

  • Bone marrow depression / blood dyscrasias (aplastic anaemia, agranulocytosis, pancytopenia, thrombocytopenic purpura)
  • Neonatal Grey syndrome
  • Peripheral neuritis; optic neuritis; blurred/transient loss of vision
  • Vomiting, diarrhoea, nausea, dry mouth
  • Fungal superinfection; urticaria

Interactions

  • Other drugs that may cause bone marrow depression — concurrent therapy should be avoided
  • Monitor serum levels particularly in neonates/premature infants, elderly, renal or hepatic disease, and with other interacting drugs

Clinical monograph

How it works

It inhibits bacterial protein synthesis by binding the 50S ribosomal subunit and blocking peptidyl transferase activity, giving a predominantly bacteriostatic effect.

Prescribing in practice

  • Systemic use carries a risk of serious, dose-independent aplastic anaemia and bone-marrow suppression, so systemic therapy is reserved for serious infections without safer alternatives.
  • Systemic use is avoided in late pregnancy and the neonatal period because of the risk of grey baby syndrome.
  • Topical ocular use is widely used and generally well tolerated for short courses.

Monitoring

During systemic therapy, monitor the full blood count closely for marrow suppression, and review duration carefully.

Counselling the patient

  • For eye preparations, report any worsening, persistent or spreading eye symptoms.
  • Seek medical advice promptly if you develop unexplained bruising, bleeding, sore throat or fever during systemic treatment.

Evidence & guidelines

Its reserved systemic role and topical ocular use are well established in UK prescribing references and microbiology guidance.

Reference: NICE CKS; 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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