Chloramphenicol

1. Introduction

Chloramphenicol is a broad-spectrum antibiotic used to treat serious bacterial infections. It is available in various forms, including eye drops, ointments, and oral formulations. While it is highly effective against a wide range of bacteria, its use is limited due to potential serious side effects, such as bone marrow suppression.

2. Indications

  • Approved Indications:
    • Bacterial conjunctivitis (eye drops and ointments).
    • Life-threatening infections caused by susceptible organisms, such as:
      • Typhoid and paratyphoid fever.
      • Meningitis (when no alternative is available).
      • Rickettsial infections.
      • Brain abscesses.
    • Topical treatment of bacterial skin infections.
  • Off-Label Uses:
    • Severe infections in patients with allergies to first-line antibiotics.

3. Dosage

  • For Bacterial Conjunctivitis:
    • Eye drops: 1 drop in the affected eye(s) every 2 hours while awake, reducing frequency as symptoms improve.
    • Eye ointment: Apply a small amount (1 cm ribbon) to the lower eyelid 3–4 times daily.
  • For Systemic Infections (Oral or IV):
    • Adults: 50–100 mg/kg/day in divided doses every 6 hours.
    • Children: 50–75 mg/kg/day in divided doses every 6 hours.
    • Maximum dose: 4 g/day.
  • For Neonates:
    • Initial dose: 25 mg/kg/day in divided doses every 6 hours (reduce dose in premature infants due to slower metabolism).

4. Administration

  • Eye Drops and Ointments:
    • Wash hands before and after application.
    • Avoid touching the dropper tip or tube to any surface, including the eye.
  • Oral or IV Formulations:
    • Administer orally with or without food.
    • For IV administration, dilute according to guidelines and administer slowly.

5. Forms Available

  • Eye drops: 0.5% solution.
  • Eye ointment: 1% concentration.
  • Oral capsules: 250 mg.
  • Injectable solution: 1 g/vial.

6. Side Effects

6.1. Common Side Effects

  • Eye irritation (eye drops/ointment).
  • Nausea and vomiting (oral or IV).
  • Diarrhoea.

6.2. Less Common Side Effects

  • Headache.
  • Dizziness.

6.3. Rare but Serious Side Effects

  • Bone marrow suppression (aplastic anaemia).
  • Grey baby syndrome (in neonates due to immature metabolism).
  • Peripheral neuropathy.

7. Warnings

  • Chloramphenicol can cause serious and potentially fatal blood disorders, including aplastic anaemia and pancytopenia. Use only when no safer alternatives are available.
  • Contraindicated in individuals with a history of hypersensitivity to chloramphenicol or related compounds.
  • Avoid long-term or repeated use due to the risk of cumulative toxicity.

8. Precautions

  • Perform baseline and periodic complete blood counts (CBC) during prolonged use to detect early signs of bone marrow suppression.
  • Use with caution in patients with liver or kidney dysfunction, as drug clearance may be reduced.
  • Avoid unnecessary use to minimise the risk of antibiotic resistance.

9. Interactions

  • Drug-Drug Interactions:
    • Anticoagulants (e.g., warfarin): Enhanced anticoagulant effect.
    • Phenytoin and phenobarbital: Reduced metabolism, increasing their toxicity risk.
    • Rifampin: May reduce chloramphenicol efficacy.
  • Drug-Food Interactions:
    • No significant interactions.

10. Monitoring Parameters

  • Complete blood count (CBC) during prolonged or high-dose therapy.
  • Serum drug levels, especially in neonates or patients with liver or renal impairment.
  • Watch for symptoms of toxicity, such as pallor, fatigue, or easy bruising (signs of bone marrow suppression).

11. Use in Children

  • Approved for use in bacterial infections but with extreme caution due to the risk of grey baby syndrome in neonates.
  • Dose adjustments are required based on age and weight.

12. Use in Pregnancy

  • Category C: Use only if the potential benefit outweighs the risk.
  • Avoid use during late pregnancy as it may cause neonatal complications, including grey baby syndrome.

13. Use in Elderly

  • Use with caution, particularly in those with liver or kidney dysfunction. Monitor for cumulative toxicity.

14. Use in Kidney Disease

  • Dose adjustment may be required in severe renal impairment due to reduced clearance.

15. Use in Liver Disease

  • Use cautiously in patients with liver disease, as metabolism and clearance of chloramphenicol may be impaired.

16. Patient Counselling Points

  • For eye infections, use the drops or ointment as prescribed. Do not share with others to prevent cross-infection.
  • Complete the full course of treatment, even if symptoms improve early.
  • Report any signs of severe side effects, such as bruising, fatigue, or unusual bleeding, immediately.
  • Avoid unnecessary use or prolonged treatment to minimise serious side effects.
  • For systemic use, regular blood tests may be required to monitor for toxicity.

17. Table of Brand Names, Manufacturers, and Prices

Brand NameManufacturerPrice (USD)
ChloromycetinPfizer$15–25 (10 mL, 0.5% eye drops)
OptrexReckitt Benckiser$10–20 (10 mL, 0.5% eye drops)
Generic OptionsVarious$5–10 (10 mL, 0.5% eye drops)

18. FAQs (15 Questions)

  1. What is chloramphenicol used for?
    It is used to treat bacterial eye infections (conjunctivitis), life-threatening infections like meningitis, and infections caused by susceptible organisms.
  2. How does chloramphenicol work?
    It inhibits bacterial protein synthesis, preventing bacterial growth.
  3. Can chloramphenicol cause side effects?
    Yes, common side effects include nausea, vomiting, and eye irritation. Serious side effects include bone marrow suppression and grey baby syndrome.
  4. How is chloramphenicol applied to the eyes?
    Use 1 drop every 2 hours for eye drops or apply a small amount of ointment to the lower eyelid 3–4 times daily.
  5. Is chloramphenicol safe for children?
    Yes, but it must be used with caution in neonates due to the risk of grey baby syndrome.
  6. Can pregnant women use chloramphenicol?
    It should be avoided unless the potential benefits outweigh the risks.
  7. Can chloramphenicol be used for viral infections?
    No, it is ineffective against viral infections.
  8. What should I do if I miss a dose?
    Take it as soon as you remember, but skip it if it’s close to the next dose.
  9. Can chloramphenicol cause anaemia?
    Yes, it can cause aplastic anaemia, a rare but serious side effect.
  10. Does chloramphenicol interact with other medications?
    Yes, it interacts with anticoagulants, phenytoin, and rifampin, among others.
  11. How long does it take for chloramphenicol eye drops to work?
    Improvement is usually seen within 48 hours.
  12. Can I wear contact lenses while using chloramphenicol?
    No, avoid wearing contact lenses during treatment.
  13. How should chloramphenicol eye drops be stored?
    Store in the refrigerator and discard after 28 days of opening.
  14. Can chloramphenicol treat ear infections?
    It may be prescribed off-label for ear infections in specific cases.
  15. How long can chloramphenicol be used?
    It is typically used for a short duration (e.g., 5–7 days). Prolonged use is avoided due to toxicity risks.