8.3 Flashcards
Glycylcyclines bind what on the bacteria?
30 s subunit
What bacteria do aminoglycosides target?
Aerobic gram negative
What are the 3 principle mechanisms by which aminoglycosides gain resistance?
- Plasmid-associated synthesis of enzymes that modify and inactivate drug
- Decreased accumulation of drug
- Receptor protein on 30S ribosomal subunit may be deleted or altered due to mutation
What is the MOA of aminoglycosides?
Irreversible binding to 30 s subunit
Why do you only give aminoglycosides once a day?
Postantiobiotic effect + concentration dependent killing (higher the conc -> greater the killing effect; massive dose once a day gives best outcome)
Which drugs are time dependent?
Penicillins
Cephalosporins
Aminoglycosides is the DOC for?
Empiric therapy of infective endocarditis in
combination with either a penicillin or (more
commonly) vancomycin
What is the DOC for Y.Pestis?
Streptomycin
What is oral neomycin used for?
Adjunct in treatment for hepatic encephalopathy
Besides oral neomycin, what are alternative treatments for hepatic encephalopathy?
- Lactulose
- Oral vancomycin
- Oral metronidazole
- Rifaximin
What is the MOA of Lactulose?
• Degraded by intestinal bacteria -> lactic acid + other organic acids
-> acidification of gut lumen
-> favors formation of NH4+ from NH3
->NH4 + is trapped in colon effectively reducing
plasma ammonia concentrations
Where are high levels of aminoglycosides going to accumulate? (2)
1) Renal cortex
2) Inner ear
Are aminoglycosides safe in pregnancy?
No -> tetratogen (category D)
