Chem Basis - Structures - Penicillins 2

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Chem Basis - Structures - Penicillins 2
2014-01-21 14:45:21
Chem Basis Structures Penicillins
Chem Basis - Structures - Penicillins 2
Chem Basis - Structures - Penicillins 2
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  1. Dicloxacillin has string B-lactamase inhibition and good oral activity, why?
    Isoxazole ring blocks B-lactamases and electron withdrawing Cl groups enhances this and adds oral activity
  2. “Cloxacillin” What is this drug?
  3. “Dicloxacillin” What is this drug?
  4. “Dox, Clox and Ox” Why does Oxacillin have decreased oral activity with comparison to Dicloxacillin and Cloxacillin?
    Does not have any electron withdrawing Cl group on the isoxazole ring and so has decreased oral activity
  5. “Oxacillin” What is this drug?
  6. “Methyl at C5 isoxazole” What is the significance of this C5 methyl group on this isoxazole derivative?
    Optimal beta lactamase inhibiting activity, since five-membered ring alone does not provide for sufficient steric hindrance to prevent the attack
  7. “Methicillin Methoxy” What is the significance of these methoxy groups on Methcillin?
    Prevent oral activity
  8. “Nafcillin Ethoxy” What is the significance of this ethoxy group on Nafcillin?
    Prevent oral activity
  9. “Nafcillin unlabeled” What is this drug?
  10. “Dicloxacillin” This drug has a C-alpha incorporated into a ring, which enhances protection against G+ Staph. aureus producing beta lactamases, alternatively what are the cons of this structure?
    Decreased potency against G+ bacteria
  11. Why should structures with C-alpha incorporated into a ring, like this one (Dicloxacillin) not be used for non-beta-lactamase producing Staph. Aureus infections?
    Because of their inferior potency against G+ bacteria compared to penicillin G and V and the potential for increasing bacterial resistance
  12. Linezolid (Zyvox) is what type of penicillin derivative?
    Oxazolidnones derivative
  13. “Linezolid unlabeled” What is this molecule?
    Linezolid, Zyvox
  14. “Linezolid N” The N circled in the picture imparts what characteristics on the molecule (Linezolid)?
    Electron donating, well tolerated and imparts improved safety
  15. “Linezolid F” The Flourine has what effect on this molecules (Linezolid) character?
    Improves antibacterial efficacy and activity
  16. “Linezolid aryl” The aryl group on Linizolid has what significance?
    Essential for activity
  17. “Linizolid 5S” The carbon center (Carbon 5) shown in the diagram of Linizolid needs to be in what configuration for the molecule to have antibacterial activity?
  18. “Linezolid acylaminomethyl” The C-5 acylaminomethyl group circled in this picture of Linizolid is important for what reason?
    Essential for good activity
  19. By what route does Linezolid have a 100% bioavailibility profile?
    Both intravenously or orally
  20. Is Linizolid metabolized by CYP450?
  21. Does Linezolid induce CYP450?
  22. Is Linizold poorly or well absorbed into the tissues?
    Well absorbed
  23. What type of metabolism does Linezolid undergo before excretion?
    Oxidation to inactive metabolites
  24. How is Linezolid excreted?
    Urine and the Gut
  25. What are the major Adverse Effects of Linezolid?
    GI issues, myelosuppression, optic neuropathy, and MOA inhibitor
  26. Why should you be cautious of antidepressant use with Linezolid?
    MOA inhibitor-additive effect can cause serotonin syndrome
  27. If Myelosuppression occurs with Linezolid use, when would you expect to see this occur?
    2-4 weeks after starting therapy
  28. If Myelosuppression occurs with Linezolid use, how would you reverse this symptom?
    Discontinue use
  29. Daptomycin (Cubicin) is what type of molecule?
    Cyclic lipopeptide
  30. What is Daptomycin effective against?
    Aerobic G+ organisms
  31. Why does Daptomycin have no cross resistance with Penicillin and Cephalosporins?
    MOA is also different
  32. What is the MOA of Daptomycin?
    Binds to bacterial membranes and causes a rapid depolarization of membrane potential leading to inhibition of protein, DNA, and RNA synthesis
  33. “Penicillin Pharmacophore Alpha Carbon” What is this carbon called?
  34. “Penicillin pharmacophore” The R" group can affect what aspects of a B-lactam?
    Oral activity and spectrum of action
  35. “Penicillin pharmacophore” What R” group would enhance oral activity?
    e-withdrawing substituent
  36. “Penicillin pharmacophore” What R” group would increase the G- spectrum?
    Polar group