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25 Cards in this Set
- Front
- Back
How do you recognize Aminoglycoside names?
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End in "mycin".
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AG's are mostly used against?
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gram negative enteric bacteria (in bacteremia and sepsis), or in combo with Vancomycin or PCN for endocarditis, or for TB
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AG MOA?
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Irreversible inhibitors of protein synthesis. Passive diffusion through porin channels in out membrane. Actively transported across cell membrane (O2 dependent). This transport powered by electrochemical gradient and coupled to a proton pump. Transport may be enhanced by PCN and vanco. Inhibited by low extracellular pH and no O2. AG binds to 30S ribosomal subunit and inhibits protein synthesis
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3 ways AG's inhibit protein synthesis?
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Interefere with initian complex
Misread mRNA Breakup ribosomes |
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3 mechanisms of AG resistance?
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1. Production of a transferase enzyme that deactivates the AG.
2. Impaired entry of AG into cell. (mutation of porin gene) 3. Alter 30S receptor |
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Why are single, large doses of AG's better?
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Concentration dependent killing. Postantibiotic effect. No more (often less) toxic.
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How are AG's secreted? What level should be monitored?
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Kidney. Creatinine Clearance should be monitored
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Do AG's reach CSF?
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AG's are largely excluded from CSF and eye, but can reach 20% of plasma levels if active inflammation is going on.
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High doses of AG’s cause a “curare like” effect of respiratory paralysis. How is this reversed?
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Calcium Gluconate or Neostigmine
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Two important side effects of AG’s?
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Ototoxic, Nephrotoxic
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Streptomycin is mainly used to treat what disease?
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TB
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Streptomycin serious side effect?
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Vestibular problems. Vertigo
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If an organism (enterococci) is resistant to gentamycin, what drug should be used?
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Streptomycin
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Streptomycin is often used in combo with what drug for Plague, Tularemia, Brucellosis?
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Oral Tetracycline
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Gentamycin is effective against?
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Gram + and - organisms.
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Gentamycin should not be used alone against what organisms? Why not?
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Staph. Resistance develops rapidly.
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Why should AG's not be used as a single agent therapy for PNA?
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penetration of lung tissue is poor, and low pH, and low O2.
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Side effects of gentamycin?
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Bad Ototoxicity, mild nephrotoxicity.
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What's the difference between gentamycin and tobramycin?
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Tobramycin is more effective against psudomonas and less effective against serratia.
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What organism is resistant to Tobramycin?
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Enterococcus faecium
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Why is Gentamycin prefered to Tobramycin?
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Gentamycin is cheaper
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When are Amikacin and Netmilcin used and why?
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Amikacin is resistant to enzymes that break down gentamycin and tobramycin (and others) so it is used against organisms that are resistant to these drugs.
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Side effect of Amikacin?
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Ototoxic, especially to auditory portion of CN VIII
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Side effects of Neomycin and Kanamycin?
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Highly Nephrotoxic and Ototoxic. Auditory>Vestibular. rarely used today.
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Spectinomycin used to tx what disease?
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Gonorrhea
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