Pharmacology Exam II

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Rx2013
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65081
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Pharmacology Exam II
Updated:
2011-02-08 20:10:42
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Penicillins
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Penicillins
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  1. Penicillins are _____ compounds
    beta lactam
  2. Beta-lactam compounds
    • penicillins
    • cephalosporins
    • monobactams
    • carbapenems
    • beta lactamase inhibitos
  3. all beta lactam compounds are ___ membered rings
    4
  4. lactams are cyclic
    amides
  5. a beta lactam ring consists of
    three carbon atoms and one nitrogen atom
  6. Substitutions of the _____ moiety determine the essential pharmacologic and antibacterial properties of the resulting molecules.
    6-aminopenicillanic acid
  7. Three groups of penicillins
    • penicillins (penicillin G)
    • Antistaphyulococcal Penicillins (nafcillin)
    • extended-specturm penicillins (ampicillin and antipseudomonal penicillins)
  8. Penicillins have greatest activity against
    • gram positive organisms
    • gram negative cocci
    • non B-lactamase producing anaerobes
  9. Penicillins have little activity against
    gram negative rods because of suceptibility to hydrolysis by beta lactamase
  10. Antistaphylococcal PCN
    resistant to staphylococcal beta lactamase
  11. Antistaphylococcal penicillins are active against
    staphylococci and streptococci
  12. Antistaphylococcal Penicillins not active against
    • enterococci
    • anaerobes
    • gram negative cocci and rods
  13. Extended spectrum PCN have improved activity against
    • gram negative organisms
    • relatively suceptible to hydrolysis by beta lactamase
  14. MIC is usually has units of
    mcg/ml
  15. Most penicillins are dispensed as
    sodium or potassium salt of the free acid
  16. In dry crystallin form PCN salts are stable for
    years at 4 C
  17. PCN mechanism of action
    interfere with transpeptidation step of cell wall synthesis
  18. Polysaccharide chains contain
    • alternating amio sugars
    • N-acetylclucosamine
    • N-acetylmuramic acid
  19. A five-amino-acid peptide is linked to the ____ sugar and terminates in ____.
    • n-acetylmuamic acid
    • d-alanyl-d-alanine
  20. Penicillin binding protien acts by removing ____ to allow cross link formation that gives the cell wall rigidity.
    terminal alanine on the 5 amino acid peptide
  21. B-lactam antibiotics are structural analogs of ____ which inhibits ___.
    • D-ala-D-ala
    • transpeptidation
  22. Beta lactam antibiotics kill bacterial cells only when
    they are actively growing and synthesizing cell wall
  23. 4 mechanisms of PCN resistance
    • inactivation by beta lactamase
    • modification of target PBPs
    • impaired penetration of drug to target PBPs
    • efflux of drug
  24. Most common mechanism of resistance to PCN
    beta lactamase production
  25. Mechanism of PCN resistance in pneumococci and enterococci
    altered target PBPs that have low affinity for binding beta lactam antibiotics
  26. PCN resistance mechanisms in gram negative species
    • impared penetration of outer cell wall membrane due to reduction in the presence of proper channels
    • efflux pumps
  27. Acid stable PCNs (3)
    • dicloxacillin
    • ampicillin
    • amoxicillin
  28. Absorption of most oral PCNs is impaired by food except
    amoxicillin
  29. PCNs formulated to delay absorption to prolong blood and tissue concentrations_____ & ____. Used for treatment of _____.
    • Benzathine
    • Procaine
    • beta-hemolytic strep
  30. PCN concentrations in most tissue are ____ to those in the serum.
    equal
  31. PCN is excreted in these fluids
    • sputum
    • milk
  32. PCN has poor penetration into
    • eye
    • prostate
    • CNS
  33. PCN is excreted by
    the kidneys
  34. 90% of renal excretion of PCN is through____ 10% through___.
    • tubular secretion
    • glomerular filtration
  35. Normal half life of PCN
    30 min
  36. Ampicillin and extended spectrum PCNs have half lives of
    1 hour
  37. Doses of PCNs must be adjusted according to
    renal function
  38. If creatinine clearance is 10mL/min or less the dose of PCN will likely be
    1/4 to 1/3 of the normal dose
  39. Nafcillin is primarily cleared by
    biliary excretion
  40. PCNs that are eliminated by both the kidney and biliary excretion
    • require no dosage change based on renal function
    • oxacillin
    • dicloxacillin
    • cloxacillin
  41. Clearance of PCN is ____ efficient in newborns
    less
  42. PCNs should be given
    1-2 hours before a meal
  43. Administration of PCNs with _____ can result in higher blood levels of PCN by inhibiting renal tubular secretion.
    probenecid
  44. Drug of choice for infections caused by streptococci, meningococci, enterococci, PCN susceptible pneumococci, non beta-lactamase producing staphylococci, spirochetes, clostridiumk actinomyces, gram positive rods and gram negative anaerobes (non beta lactamase)
    Penicillin G
  45. Benzathine PCN and procaine PCNG IM injections result in
    low but prolonged drug levels
  46. Benzathine PCN(1.2 million units) may be given 1 time for treatment of beta strep and repeated once every ____ to prevent reinfection
    3-4 weeks
  47. Benzathine PCN G (2.4 million units) IM once is effective in the treatment of
    syphilis
  48. PCNs that are resistant to staphylococcal beta lactamase
    • methicillin
    • nafcillin
    • isoxazoyl PCNs
  49. Strains of staphylococcie that are resistant to beta lactamase resistant PCNs
    • listeria
    • enterococci
    • methicillin resistant strains
  50. Methicillin, Nafcillin and Isoxazolyl PCNs are considered drugs of choice for
    methicillin susceptible strains of staph
  51. Extended spectrum PCNs
    • aminopenicillins
    • carboxypenicillins
    • ureidopenicillins
  52. Extended spectrum PCNs have greater activity against gram negative bacteria because of
    • enhanced ability to penetrate gram negative outter membrane
    • still succeptible to beta-lactamase
  53. Aminopenicillin, ampicillin and amoxicillin
    • same spectrum of activity
    • amoxicillin is better absorbed
    • given orally to treat UTI, sinusitis, otitis and lower resp. infections
  54. Most active oral beta lactams against PCN resistant pneumococci and prefered for this use
    • Ampicillin
    • Amoxicillin
  55. Most serious side effect of PCN
    hypersensitivity
  56. incidence of allergic reactions to PCN in children is
    negligible
  57. other ADRs associated with PCNs
    • oral lesions
    • fever
    • interstitial nephritis
    • eosinophilia
    • hemolytic anemia
    • vasculitis
  58. In pt with renal failure,PCN can cause
    seizures
  59. Nafcillin is associated with
    neutropenia
  60. oxacillin can cause
    hepatitis
  61. Large doses of oral PCNs may lead to
    • GI upset
    • n/v
    • diarrhea
  62. Rashes resulting from ampicillin and amoxicillin frequently occur when
    aminopenicillins are inappropriately prescribed for a viral illness

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