Pharmacology Exam II

  1. tetracyclines are named for their
    four hydrocarbon rings
  2. Free tetracyclines are _____ substances of ____ solubility
    • amphoteric
    • low
  3. Tetracyclines are generally available as ____ which are more soluble and fairly stable
  4. Interferance with absorption of tetracyclines
    chelation of divalent metal ions
  5. Introduced to treat infections which are resistant to other antimicrobics including tetracyclines
  6. Mechanism of action for tetracyclines
    protein synthesis inhibition by binding the 30s subunit of the bacterial ribosome
  7. Activity of tetracyclines
    • broad specturm bacteriostatic
    • gram positive and negative
  8. tetracycline resistant strains may be susceptible to ____ because they are______
    • doxycycline
    • minocycline
    • tigecycline
    • poor substrates for efflux pump
  9. tetracyclines enter cells via
    passive diffusion and active transport
  10. 3 mechanisms of resistance to tetracyclines
    • impaired influx or increased efflux
    • ribosome protection by proteins that interfere with tetracycline binding
    • enzymatic inactivation of tetracycline
  11. most important mechanisms of resistance to tetracyclines
    • production of an efflux pump
    • ribosomal protection
  12. Confers resistance to older tetracyclines such as doxycylcine and minocycline
    Tet(AE) efflux pump-expressing gram negative species
  13. TET(AE) efflux pump expressing species are susceptible to
  14. Tet (K) efflux pump of staphylococci confers resistance to tetracycline but not
    • doxycycline
    • minocycline
    • tigecycline
  15. proteus pseudomonas is resistant to all tetracyclines (including tigecycline) due to the
    multidrug efflux pumps
  16. # of classes of ribosomal protection genes/proteins
    6 classes
  17. mechanisms of action of ribosomal protective proteins
    • block tetracylcines from binding to the ribosome
    • distort structure of ribosome to allow t-RNA binding while TCN is bound
    • binding the ribosome to dislodge the TCN
  18. Tet (M) expressed by gram positive bacteria produces resistance to
    • tetracycline
    • doxycycline
    • minocylcine
  19. Tet (M) does not confer resistance to ____ because of its _____
    • tigecycline
    • bulky t-butylglycylamido group
  20. Rarest type of TCN resistance
    • enzymatic inactivation
    • acetyl group is added to the TCN which results in inactivation
  21. chlortetracycline oral absorption
  22. TCN, oxyTCN, demeclocycline and methacycline absorption
  23. Absorption of 95-100%
    • doxycycline
    • minocycline
  24. Tigecycline administration
    IV only
  25. Absorption of TCNs occurs in
    • small intestines
    • impaired by food and divalent cations
  26. TCN should be taken
    1 hr before or 2 hrs after eating with a full glass of water
  27. Reaches very high concentrations in tears and saliva which makes it useful for eradication of the meningococcal carrier state
  28. TCN excretion
    • cross placenta and milk
    • bind to bones and teeth (growing)
    • excreted mainly in bile and urine
  29. TCN metabolism induced by
    • carbamazepine
    • phenytoin
    • barbiturates
    • chronic alcohol consumption
  30. TCNs that require no dosage adjustments based on renal function
    • doxycycline
    • tigecycline
  31. Naturally occuring TCNs
    • TCN
    • chlortetracycline
    • oxytetracycline
    • demeclocycline
  32. Semi-synthetic TCNs
    • doxycycline
    • lymecycline
    • meclocycline
    • methacycline
    • minocycline
    • rolitetracycline
  33. Short acting TCNS (6-8hr half life)
    • TCN
    • chlortetracycline
    • oxytetracycline
  34. Intermediate acting half life 12 hr
    • Demeclocycline
    • methacycline
  35. Long acting TCNs (16 hrs or more)
    • doxycycline
    • minocycline
    • tigecycline (36hrs)
  36. TCN is the drug of choice for infections with
    • mycoplasma pneumoniae
    • chlamydiae
    • rickettsiae
    • spirochetes
  37. TCNs are used in combo regimens to treat
    gastric and duodenal ulcer disease caused by H. Pylori
  38. TCN in combo with aminoglycoside is indicated for
    • plague
    • tularemia
    • brucellosis
  39. TCN are no longer recommended for treatment of
    gonococcal disease because of resistance
  40. Oral TCN of choice
    • Doxycycline
    • once daily dosing
    • absorption not significantly affected by food
  41. Adverse reactions with TCN
    • chelation with metals
    • avoid in pregnant and children less than 8 due to deposition in growing bones and teeth
    • mostly due to direct toxicity or alteration of microbial flora
  42. GI adverse effects of TCN
    • n/v
    • diarrhea
  43. Avoiding GI ADRs associated with TCNs
    • administer with food or carboxymethycellulose
    • reduce dose
    • discontinue therapy
  44. Liver toxicity with TCN may occur when:
    • used in pregnancy
    • used in pt with hepatic insufficiency
    • high doses given IV
  45. Hepatic necrosis has been reported with daily doses of TCN of ____ or more IV
  46. Fanconi Syndrom
    • potentially fatal disease affecting proximal tubular function in the nephrons caused by breakdown products from expired TCN.
    • Discard drugs when expired
  47. usage of expired tetracycline can result in
    • fanconi syndrome
    • renal tubular acidosis
    • renal nitrogen retention
  48. TCN + Diuretics may produce
    renal nitrogen retention
  49. TCNs other than doxycycline with impaired renal function
    may accumulate to toxic levels
  50. Intravenous injection of TCN can lead to
    venous thrombosis
  51. IM injection of TCNs can lead to
    local painful irritation
  52. TCNs espcially demecloclycline can lead to these other reactions
    • photosensitization
    • vestibular reactions (35-70% of minocylcine pt)
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Pharmacology Exam II