Chloramphenicol Uses, Side Effects, and More

 Chloramphenicol

Brand name:- Chloromycetin,Enteromycetin,Paraxin 250,500mg cap. 

Chloramphenicol was initially obtained from streptomyces venezuelae in 1947 . It was soon synthesized chemically and the commercial product now is all synthetic.

It is a yellowish white crystalline solid, aqueous solution is quite stable, stands boiling, but needs protection from light. The nitrobenzene moiety of chloramphenicol is probably responsible for the antibacterial activity as well as its intensely bitter taste.

Mechanicsm of action:-

Chloramphenicol inhibits bacterial protein synthesis by interfering with 'transfer' of the elongating peptide chain to the newly attached aminoacyl-tRNA at the ribosome- mRNA complex. It specifically attaches to the 50S ribosome near the acceptor (A) site and prevents peptide bond formation between the newly attached aminoacid and the nascent peptide chain without interfering with the aminoacyl-tRNA attachment to the 30S ribosome (the step blocked by tetracycline). 

 At high doses, it can inhibit mammalian mitochondrial protein synthesis as well. Bone marrow cells are especially susceptible.

 Pharmacokinetics:- 

Chloramphenicol is rapidly and completely absorbed after oral ingestion. It is 50-60%  bound to plasma proteins and very widely distributed: volume of distribution 1 L/kg . It freely penetrates serous cavities and blood - brain barrier: CSF concentration is nearly equal to that of unbound drug in plasma. It crosses placenta and is secreted in bile and milk. 

 Chloramphenicol is primarily conjugated with glucuronic acid in the liver and little is excreted unchanged in urine. Cirrhotics and neonates, who have low conjugating ability, require lower doses. The metabolite is excreted mainly in urine. Plasma t½ of chloramphenicol is 3-5 hours in adult. It is increased only marginally in renal failure: dose need not be modified.

Pharmacodynamic:- 

Chloramphenicol is a broad-spectrum antibiotic that was derived from the bacterium Streptomyces venezuelae and is now produced synthetically. Chloramphenicol is effective against a wide variety of microorganisms, but due to serious side-effects (e.g., damage to the bone marrow, including aplastic anemia) in humans, it is usually reserved for the treatment of serious and life-threatening infections (e.g., typhoid fever). Chloramphenicol is bacteriostatic but may be bactericidal in high concentrations or when used against highly susceptible organisms. Chloramphenicol stops bacterial growth by binding to the bacterial ribosome (blocking peptidyl transferase) and inhibiting protein synthesis.

Used:- 

used in the treatment of bacterial infections. It is used to treat certain types of serious infections caused by bacteria when other antibiotics cannot be used.

side effects:- 

Temporary blurred vision, burning, stinging, or redness may occur. 

Dose:-  AS directed by your doctor.