Kinetics Quiz 1

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Kinetics Quiz 1
2011-01-18 22:28:34
Intro Kinetics

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  1. Pharmacokinetics is defined as the study of the time course of
    • drug absorption
    • distribution
    • metabolism
    • excretion
  2. CLinical pharmacokinetics
    application of pharmacokinetics to the safe and effective management of drugs in an individual
  3. Principle application of clinical pharmacokinetics
    • increase effectiveness
    • decrease toxicity
  4. Pharmacodynamics
    relationship between drug concentration at the site of action and pharmacologic response
  5. fluid most often sampled for drug concentration
  6. describes the predictable relationship between plasma drug concentration and concentration at the receptor site
    kinetic homogeneity
  7. If the plasma drug concentration is decreasing, the concentration in the tissues will _____.
  8. Plasma concentration that is effective and safe in treating specific diseases
    therapeutic range
  9. boundaries dividine subtherapeutic, therapeutic and toxic drug concentrations
    no absolute boundaries
  10. Variability in patient's response is influenced by both
    pharmacodynamic and pharmacokinetic factors
  11. pharmacokinetics of a drug determine
    blood concentration achieved
  12. Pharmacokinetic factors causing variability in the plasma drug concentration
    • differences in individual metabolism and elimination
    • variations in absorption
    • disease states or physiologic states
    • drug interactions
  13. Determination of plasma drug concentrations to optimize a patient's drug therapy is known as
    therapeutic drug monitoring
  14. Two components of therapeutic drug monitoring
    • assay for [drug] in plasma
    • interpretation of resulting concentration to develope a safe drug regimen
  15. Therapeutic monitoring is valuable when
    • good correlation exists between pharmacologic response and plasma concentration
    • wide variation in drug levels in patients
    • drug has a narrow therapeutic index
    • drug's effects cannot be measured by other means (BP)
  16. Value of therapeutic drug monitoring is limited in situations where
    • no well defined therapeutic [plasma] range
    • formation of active metabolites
    • toxic effects at low and high concentrations
  17. compartmental models are called "deterministic" because
    the observed drug concentrations determine the type of compartment model required
  18. describes change in the amount of drug in the body
    elimination rate
  19. Bolus
    drug dose is given over a very short time
  20. Concentration of a drug =
    amount of drug/volume in which it is distributed
  21. Volume of distribution
    extent of drug distribution into body fluids and tissues
  22. usually indicates that the drug distributes extensively into body tissues and fluids
    large volume of distribution
  23. indicates limited drug distribution, possibly into the plasma only
    small volume of distribution
  24. When V is many times the volume of the body
    drug concentrations in some tissues may be higher than in the plasma
  25. The smallest volume that a drug may distribute in is
    • the plasma (4%)
    • 3 L
  26. A straight line is obtained from the natural log of plasma drug concentration versus time plot only for drugs that follow
    first order elimination
  27. First order elimination occurs when
    amount of drug eliminated depends on the amount of drug in the body at that time
  28. A large volume of distribution indicates that
    a larger dose should be administered to achieve a target concentration
  29. volume of extracellular fluid in the body
    • 15-18 L
    • 25%
  30. Total body water
    • 40 L
    • 60%
  31. Extracellular fluid is made up of
    plasma and interstitial fluid
  32. fluid portion in combination with formed elements
  33. fluid portion of blood
  34. fluid portion of blood when soluble protein fibrinogen is removed
  35. Interstitial fluid
  36. Intracellular fluid
  37. To examine the one compartment model, two assumptions are made
    • distribution and equilibration is instantaneous
    • elimination is first order
  38. Amount of drug eliminated for each timer interval is constant, regardless of the amount in the body
    zero order elimination
  39. the fraction of a drug in the body eliminated over a given time remains constant in
    first order elimination
  40. natural log of concentration vs. time plot is linear
    first order elimination
  41. plasma concnetration vs time plot is linear
    zero order elimination
  42. ln of plasma concentration vs time plot is non-linear
    zero order elimination
  43. Y =
  44. A steep slope indicates a ____ rate of elimination than a flat slope
  45. slope =
    - elimination constant
  46. fraction of drug removed over a unit of time
    elimination rate constant
  47. equation for ln C
    ln C = (-K x t) + ln C0
  48. time necessary for the concentration of drug in the plasma to decrease by one half
    half life
  49. half life expresses the same idea as
    elimination rate constant
  50. first order reaction T1/2 =
  51. Dependent variable
  52. independent variable
  53. T1/2 for zero order half life
    = 0.5(At)/K0
  54. Half life is not a constant and will decrease as the process continues
    zero order half life
  55. Mammillary compartment model
    grouped around a central compartment
  56. Volume of distribution = 5 L
    entire blood
  57. Half life is constant and will not change as the process continues
    first order half life
  58. Idea behind pharmacokinetics
    know the concentrations at times labs were drawn
  59. slope of a first order plot =
  60. clearance =
    V * K
  61. Clearance has the units of
    • flow
    • volume per time (ml/min, L,hr)
  62. the rate at which a volume of blood is being cleared from drug molecules