Chloramphenicol

Question 1

MOA

Answer 1

binds reversibly to the 50S ribosomal subunit at a site that is near the erythromycin and clindamycin

inhbits peptidyl transferase actvitiy of hte ribosome and blocks peptide bond formation between P and A site

Question 2

therapeutic use

Answer 2

bacterial meningitis, typhoid fever, rickettsial infections, intraocular infections, and other serious infectiosn where bacteriological evidencde or clincial judgement indicates chloramphenicol

Question 3

PK

Answer 3

lipid soluble , unbound to plasma, penetrates effectively into all tissues of the body and brain

Question 4

Resistance mechanism

Answer 4

1. reduced membraine permeability
2. mutaation of the 50S ribosomal subunit
3. elaboration of chloramphenico acetyltransferase

Question 5

Metabolism

Answer 5

metabolized to its glucuronide in the liver (dose must be reduced in liver impairment)

Question 6

toxicity

Answer 6

• aplastic anemia (highest risk with oral chloramphenicol)
• check blood levels for conc less than 25 ug/mL
• bone marrow suppression
• increased childhood leukemia

Question 7

drug interactions

Answer 7

P450

Question 8

Distributions

Answer 8

• brain and CSF is about 30-50%
• 89% when meninges are inflammed

Question 9

Does bone marrow suppression predict aplastic anemia development

Answer 9

no, is completely revresible once drug is stopped