Chloramphenicols Flashcards
Are chloramphenicols natural or synthetic
Synthetic
Are chloramphenicols static or cidal?
Static
Derivatives of chloramphenicols
Thiamphenicol
Florfenicol
MOA chloramphenicols
Reversibly binds to 50s subunit
Inhibits peptidyl transferase – inhibits peptide formation
T/F - chloramphenicols can inhibit protein synthesis in mammals
TRUE! Chronic use can result in bone marrow suppression and pancytopenia
Spectrum of chloramphenicols
Broad
Gram+/-
Anerobes
Mycoplasma
Rickettsia
Absorption of chloramphenicols
Highly lipid soluble: good oral and parental use
Can chloramphenicols be given to ruminants orally?
No - inactivated by ruminal microbes
T/F chloramphenicol diffuses into milk
True - and crosses placental barrier
Can chloramphenicols be used to treat CNS or respiratory infections
YES!
How are chloramphenicols metabolized? **
Liver – glucuronidation
How do chloramphenicol metabolism differ with age?
Young animals - slower
Do cats metabolize chloramphenicols slower or faster?
Slower - because they lack glucuronidase enzyme!
Excretion of chloramphenicol
Urine - tubular secretion
Bile (active)
You have a dairy cow with a respiratory infection. Can you give chloramphenicol?
NO! Prohibited in food animals because it causes APLASTIC ANEMIA in people
What is an adverse effect of chloramphenicol in some humans
Aplastic anemia
What are adverse effects of chloramphenicols
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
Which chloramphenicol derivatives dont cause bone marrow toxicity
Thiamphenicol
Florfenicol
Can you give thiamphenicol or florfenicol to food animals
Yes! They dont induce bone marrow toxicity
Drug interactions of chloramphenciols?
Inhibits cytochrome P450
Competes for site of action with macrolides and lincosamides — never give together!
Which other drugs should choramphenicols never be given with?
Macrolides and lincosamides (antibacterial antagonism)
Bacterial resistance to chloramphenicols
Acquired, plasmid-mediated resistance
Due to synthesis of chloramphenicol transacetylase enzyme
Are any chloramphenicol derivatives resistance to bacterial resistance
Florfenicol
Which chloramphenicol derivative is less potent
Thiamphenicol (water soluble)
T/F - thiamphenicol and florfenicol are excreted as active form
True
Which chloramphen derivative is good for genitourinary tract infections
Florfenicol
Where is florfenicol injected
SC/IM region
Efficacy predictor of Chloramphenicol
Type II (time dependent)
