Phenicols

Question 1

Source and chemistry:

Answer 1

Streptomyces venezuelae.
Lipophilic, small molecule.
Excellent pharmacokinetic.
Excretion in bile.

Question 2

Mechanism and mode of action:

Answer 2

Inhibition of protein synthesis 50S- don’t combine with other 50S.
Bacteriostatic.

Question 3

Resistance:

Answer 3

Active efflux pump.
Decreased uptake.
Acetyltransferase- inactivates.

Question 4

Spectrum:

Answer 4

Broad, gram+ and gram-
NOT Pseudomonas!
Mycoplasma, Rickettsia, Chlamydia
Aeromonas salmonicida- Florphenicol is the only licensed for fish.

Question 5

Pharmacokinetics:

Answer 5

Absorption: excellent 80-100% oral, SC, IM, eye absorb -> can lead to death as SE.
Distribution: Excellent, can go everywhere- BBB, prostate, placenta, bones, IC.
Best pharmacokinetics of all antibacterials.
Metabolism: extensive in the liver, careful giving to liver and kidney patients.
Urine: inactive, so not in UTI.
Half life: longer in ru than in dog.

Question 6

Side effects:

Answer 6

Anemia- dose dependent/independent- inhibits protein synthesis in BM after 7-10 days of treatment.

Chloramphenicol LETHAL anemia in humans! Don’t give to food producing animals!

Long term: immunosuppression. Don’t vaccinate close to use.
Pain at injection site.

Question 7

Chloramphenicol:

Answer 7

DON’T USE IN FOOD PRODUCING ANIMALS!
TABLE 2 DRUG.
Can cause lethal anemia in humans.
Wear gloves when handling.

Question 8

Indications (and drugs):

Answer 8

Food producing animals: Florphenicol- respiratory disease, mycoplasma, fastidious. Foot disease, infectious keratoconjuctivitis.

Fish: aeromonas infection.

Small animals: eye infection, prostatitis, meningitis, MRSP, MRSA inf.