C.11 Chloramphenicol, Polymyxins, antifolate drugs

Question 1

Chloramphenicol general

Answer 1

Protein synthesis inhibitor

acitivity and clinical uses:

• Bacteriostatic with wide spetrum of activity
• Currently a backup rug for infection due to salmonella typhi, B fragilis, Rickettsia and possibly in Bacterial meningitis.

Mechanism:
binds reversible to the bacterial 50s ribosomal subunit (bacteriostatic)

Kinetics:

• MOst commonly administered orally, but also IV is used, with good tissue distribtuion including CSF.
• Metabolized by hepatic glucuridation which requires dose reductions in liver and in neonates.
• inhibition of cytochrome P450.

Side effects:
Dose dependent bone marrow supression which is common-> aplastic anemia
- Gray baby syndrome in neonates (

Question 2

mechanism of chrloamphenicol

Answer 2

binds reversible to the bacterial 50s ribosomal subunit (bacteriostatic).

Question 3

Kinetics of chloramphenicol

Answer 3

Kinetics:

• IV/ ORAL effective, with good tissue distribtuion including CSF.
• Metabolized by hepatic glucuridation which requires dose reductions in liver and in neonates.
• inhibition of cytochrome P450.

Question 4

Spectrum of chloramphenicol

Answer 4

Gram + Anerob and anerob- yes
Gram - Anerob and anerob- yes
And some atypical pathogens

Broad spectrum antibiotics
Active against whats mentioned above,
Worth note bacteria include:
Ricketssiae and some other atypical

Question 5

Indications include

Answer 5

rarely used
1. Haemophylus influenzae infection,
2; Neisseria meningitidis
3/ treatment of meningococcal meningitis in case of penicillin hypersensitivity
4/ bacterial meningitis
5/ treatment of eye infection in eye drops

Question 6

ADverse effect:

Answer 6

1. Gray baby syndrome (due to low capacity to glucuronidate) babies will suffer from icterus, poor feeding, depressed breathing and CV collapse. Adults in high dosages can also show this.
2. bone marrow supression (aplastic anemia in G6pd patients).
3. GI disturbances

Question 7

drug interactions of chloramphenicol

Answer 7

warfarin and phenytoin.