10th lecture - broad-spectrum antibiotics Flashcards
Broad-spectrum antibiotics are effective against
both gram neg. and pos. bacteria
Tetracyclines are
broad-spectrum, bacteriostatic;
inhibit the protein synthesis of microbes.
Resistance occurs relatively quickly.
Cross-resistance occurs with penicillins.
Tetracyclines Pharmacokinetics
Well absorbed in case of all routes of administration.
They undergo the enterohepatic circulation if administered through the oral route.
They are eliminated through the kidneys and in the bile.
Tetracyclines accumulate in
calcium-containing tissue (bones and teeth), forming a stable complex with calcium.
It is not recommended to administer to young animals.
Tetracyclines Toxicity
Have an irritant effect both when administered PO and injection (vomiting, pain at the site of the injection and tissue damage).
The animal may collapse in case of administration into the vein.
Tetracyclines may lead to kidney damage, dehydration, haemoglobinuria and an overdose will lead to liver damage.
Name 4 examples of Tetracyclines
Tetracycline hydrochloride
Oxytetracycline hydrochloride
Doxycycline hyclate
Minocycline hydrochloride
Chloramphenicol, thiamphenicol and florfenicol are all?
Broad-spectrum and bacteriostatic.
They suppress the metabolism of microbes.
Chemically similar while toxicity and pharmacokinetics are different.
Describe Chloramphenicol
Broad-spectrum, potent, the most toxic antibiotic drug in existance.
Is used primarily for topical treatment.
Prohibited for use in farm animals.
Do not administer Chloramphenicol with
other antibiotics, especially bactericidal antibiotics, antagonism will occur.
Chloramphenicol Increases the potency of
barbiturates, phenylbutazone, xylazine and ketamine.
Do not use together with these substances, this may cause death.
Chloramphenicol toxicity
the most toxic antibiotic drug in existance.
Due to extremely high toxicity, it is only recommended to use it locally, primarily for the treatment of eye and ear infections.
Damages bone marrow, inhibits haematopoiesis - aplastic anaemia.
Chloramphenicol side effects
It has been found to cause depression, dehydration, loss of appetite, vomiting and loss of body mass.
Damages bone marrow, inhibits haematopoiesis - aplastic anaemia.
Chloramphenicol Pharmacokinetics, absorption
It is well absorbed in case of all routes of administration.
Half-life varies among species.
Penetrates the barriers of the organism well. Therapeutic concentration reached quickly in all body fluids.
Chloramphenicol Pharmacokinetics, excretion
Mainly excreted in urine, also partially in the bile.
Thiamphenicol is a
broad-spectrum derivative of chloramphenicol with lower activity compared to chloramphenicol, significantly lower toxicity too.
Not prohibited for use in farm animals like chlormaphenicol is.
It is absorbed and distributed well, primarily excreted with urine.
Florfenicol is a
broad-spectrum Fluorinated derivative of thiamphenicol.
Spectrum of activity is similar to that of chloramphenicol with a lower toxicity.
After prolonged use, bone marrow damage may develop.
Primarily used for the treatment of respiratory tract infections in cattle and treatment of furunculosis in fish.
Fluoroquinolones are…?
Broad-spectrum, bactericidal.
Resistence occurs relatively quickly. Quinolones should be left as the so-called “reserve antibiotics”.
Fluoroquinolones Mechanism of action..?
They inhibit the DNA synthesis of microbes, are batericidal.
Activity against microbes depends on the concentration level. Bacteriostatic effect (paradoxical) prevails at higher concentrations.
Fluoroquinolones Pharmacokinetics, absorption and excretion
Well absorbed and distributed in case of all routes of administration.
They are metabolised in the liver and excreted with urine and in the bile.
Fluoroquinolones may lead to what after long term therapy?
They may lead to joint cartilage erosion, not recommended for young animals.
They may also cause vomiting, diarrhoea and sometimes nervous symptoms (cramps, shivers).
Name some Fluoroquinolones examples
Enrofloxacin and ciprofloxacin
Marbofloxacin
Danofloxacin
Difloxacin
Orbifloxacin