Chloramphenicol is a broad-spectrum bacteriostatic and bactericidal antibiotic. It inhibits bacterial protein synthesis by binding reversibly to the 50S subunit of the bacterial ribosome, inhibiting peptidyl transferase and preventing the transfer of elongating peptide chains. While effective against a variety of bacteria, it can cause serious and sometimes fatal side effects like bone marrow suppression and gray baby syndrome in neonates due to immature drug metabolism pathways. As a result, it is now rarely used due to toxicity concerns and the availability of alternative antibiotics.

1. Chloramphenicol

5. Pharmacokinetics Chloramphenicol palmitate (oral) Chloramphenicol succinate (Parenteral) through oral route – completely & rapidly absorbed Dose : 50 - 100 mg/kg/day Wide tissue distribution ( body fluids, CSF ) Inactivated by glucuronide conjugation Eliminated in urine, bile, feces

6. 1-10µg/ml - inhibits Gram +ve bacteria O.2-5µg/ml - inhibits Gram -ve bacteria Resistance due to chloramphenicol acetyl transferase decreased permeability into bacterial cells Cross resistance seen between Chloramphenicol, Macrolides, Lincosamide

8. Typhus

9. Rocky Mountain Spotted Fever

10. Meningococcal meningitis

13. aplastic anemia (idiosyncratic), irreversible, prolonged useGray Baby Syndrome

14. Gray baby syndrome stops feeding Vomiting Hypotonic Hypothermic Distended abdomen Irregular respiration Ashen gray cyanosis Cardiovascular collapse Death

15. Why Gray baby syndrome occurs in neonates ? Inability of neonate to metabolise & excrete chloramphenicol due to deficiency of glucuronosyl transferase At higher concentration it inhibits electron transport in liver, heart, skeletal muscle