Chloramphenicols

Question 1

Are chloramphenicols natural or synthetic

Answer 1

Synthetic

Question 2

Are chloramphenicols static or cidal?

Answer 2

Static

Question 3

Derivatives of chloramphenicols

Answer 3

Thiamphenicol

Florfenicol

Question 4

MOA chloramphenicols

Answer 4

Reversibly binds to 50s subunit

Inhibits peptidyl transferase – inhibits peptide formation

Question 5

T/F - chloramphenicols can inhibit protein synthesis in mammals

Answer 5

TRUE! Chronic use can result in bone marrow suppression and pancytopenia

Question 6

Spectrum of chloramphenicols

Answer 6

Broad

Gram+/-
Anerobes
Mycoplasma
Rickettsia

Question 7

Absorption of chloramphenicols

Answer 7

Highly lipid soluble: good oral and parental use

Question 8

Can chloramphenicols be given to ruminants orally?

Answer 8

No - inactivated by ruminal microbes

Question 9

T/F chloramphenicol diffuses into milk

Answer 9

True - and crosses placental barrier

Question 10

Can chloramphenicols be used to treat CNS or respiratory infections

Answer 10

YES!

Question 11

How are chloramphenicols metabolized? **

Answer 11

Liver – glucuronidation

Question 12

How do chloramphenicol metabolism differ with age?

Answer 12

Young animals - slower

Question 13

Do cats metabolize chloramphenicols slower or faster?

Answer 13

Slower - because they lack glucuronidase enzyme!

Question 14

Excretion of chloramphenicol

Answer 14

Urine - tubular secretion

Bile (active)

Question 15

You have a dairy cow with a respiratory infection. Can you give chloramphenicol?

Answer 15

NO! Prohibited in food animals because it causes APLASTIC ANEMIA in people

Question 16

What is an adverse effect of chloramphenicol in some humans

Answer 16

Aplastic anemia

Question 17

What are adverse effects of chloramphenicols

Answer 17

Bone marrow suppression (chronic use)

Aplastic anemia (humans)

Bon marrow toxicity

Hepatotoxicity (youngsters, cats, liver failure)

Diarrhea/intestinal damage and reduced glucose absorption in calves

Question 18

Which chloramphenicol derivatives dont cause bone marrow toxicity

Answer 18

Thiamphenicol

Florfenicol

Question 19

Can you give thiamphenicol or florfenicol to food animals

Answer 19

Yes! They dont induce bone marrow toxicity

Question 20

Drug interactions of chloramphenciols?

Answer 20

Inhibits cytochrome P450

Competes for site of action with macrolides and lincosamides — never give together!

Question 21

Which other drugs should choramphenicols never be given with?

Answer 21

Macrolides and lincosamides (antibacterial antagonism)

Question 22

Bacterial resistance to chloramphenicols

Answer 22

Acquired, plasmid-mediated resistance

Due to synthesis of chloramphenicol transacetylase enzyme

Question 23

Are any chloramphenicol derivatives resistance to bacterial resistance

Answer 23

Florfenicol

Question 24

Which chloramphenicol derivative is less potent

Answer 24

Thiamphenicol (water soluble)

Question 25

T/F - thiamphenicol and florfenicol are excreted as active form

Answer 25

True

Question 26

Which chloramphen derivative is good for genitourinary tract infections

Answer 26

Florfenicol

Question 27

Where is florfenicol injected

Answer 27

SC/IM region

Question 28

Efficacy predictor of Chloramphenicol

Answer 28

Type II (time dependent)