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22 Cards in this Set
- Front
- Back
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What does chemotherapeutic encompass? |
antibiotic, antimicrobials, and drugs in the treatment of cancer |
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What does antimiccrobials encompass? |
Any substance with sufficient antimicrobal activity that can be used in the treatment of infectious diseases |
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What does antibiotics encompass? |
Antimicrobials of microbial origin produced by fungi or by soil bacteria |
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Who is Dr. Paul Ehrlich |
Founder of modern chemotherapy: "What we want is a specific chemotherapy to kill the microbes and not ourselves" |
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What is selective toxicity? |
Selective inhibition (and killing) of the microorganisms without damage to the host |
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What are the different antibacterial targets? |
1. Cell wall biosynthesis 2. Biosynthesis of nucleic acid precursors 3. Protein synthesis 4. DNA/RNA synthesis |
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What antibacterial target is very unique and selective toxicity is achieved? |
Cell wall biosynthesis |
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How do antibacterials target biosynthesis of nucleic acid precursors? |
Tetrahydrofolic acid (THFA) biosynthesis pathway; preferential (competitive) inhibition |
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How do antibacterial agents that target protein biosynthesis work? |
differences betweenprokaryotic and eukaryotic ribosomes renderes ST, but similar enoughthat high doses of some antibiotics have toxic side effects on humans |
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How do we not target ourselves with antibacterial agents that target DNA/RNA synthesis? |
-DNA: differences related tocircular chromosome in bacteria (topoisomerase) rendersST -RNA: bacterial RNA polymerasebeta-subunit is target |
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Describe bacteriostatic activity |
-the ability ofanti-infective to inhibit the growth of a microorganism -Reversibleaction |
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Describe bactericidial activity |
-is the ability of ananti-infective agent to kill a microorganism -irreversibleaction autolysinmay be involved, or some kind of suicidal mechanism may be involved |
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Narrow-spectrum (NS) agents are restricted to what type of organism? |
Gram + organism |
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Broad-spectrum (BS) agents are targeted against what organisms? |
Gram + and gram - organisms |
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Extended-spectrum (ES) agents are targeted against what organisms? |
have much broadereffectiveness against a variety of G+, G-, and multiply resistant pathogens and may includeanaerobes |
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Define synergy. |
-effectiveness of the Abxtogether is greater than that of either drug alone -twodifferent targets chosen; one must facilitate mechanism of action (MOA) of the others |
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When is synergy a must? |
- In a complicated infection, synergistic combination of abx for 99.9% killing in the body fluid, is a must |
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What is antagonism? Give an example. |
-bacteriostatic effect ofone Abx reduces the cidal effect of the 2nd abx Ex. KnowingPen only kills dividing bacteria, an abx that inhibits cell growth,at the same time that pt. is receiving pen, isunwise |
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What is an exception of antagonism |
-Exception: in anuncomplicated infection, due to presumed G+ or G- or anerobe or intracellular bacteria,combination may be allowed |
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What is therapeutic index? |
An important limitation isthat antimicrobial drugs may have adverse or side effects (or toxicity) on the host |
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How do you calculate therapeutic index? |
Toxic dose/ Effective dose = Therapeutic index |
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T/F The toxic dose is always greater then the effective dose |
False, you expect toxic dose to be greater than achievablelevel in the body fluid;however, that does not happen because many abx trigger some kind of hypersensitivityeven in subMIC dose |
