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2011-01-24 02:56:13

chapter 2 part 3 (starts at pharmacokinetics)
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  1. what is the movement of drugs through the body?
  2. what 5 things does pharmacokinetics relate to?
    • drug's absorption
    • distribution in the body
    • distribution to site of action
    • metabolism of drug
    • excretion of drug
  3. what are the 3 properties that influence movement
    • molecular size
    • lipid solubility
    • degree of ionization depends on pH of site
  4. ______ molecules are lipid soluble and pass through biologic membranes easiliy
  5. _____ drugs are water soluble and must pass through water pores of the biologic membrane or be transported through the membrane by specialized transport mechanisms
  6. ionized drug movements depend on 3 types of transport?
    • filtration
    • passive diffusion
    • specialized transport mechanism
  7. what are two types of specialized transport mechanisms?
    • facilitated diffusion
    • active transport
  8. what is the process where small water soluble substances may pass through aqueous channels or water pores in cell membranes?
  9. nonionized forms of drugs readily cross biologic membranes along a concentration gradient until equilibrium is reached, this is known as?
    passive diffusion
  10. how do large ionized water soluble drug molecules cross the biologic membrane?
    specialized transport mechanisms
  11. what process is it when a drug forms a complex with a component of the cell membrane and is carried through the membrane and release?
    facilitated diffusion
  12. what process is the movement of drug molecules across biologic membranes against both a concentration and an electrochemical gradient?
    active transport
  13. what form of specialized transport requires energy?
    active transport
  14. what are the six factors that influence absorption?
    • degree of ionization
    • formulation (liquid or solid)
    • concentration
    • circulation to area
    • area of absorptive surface
    • route of administration
  15. what can delay dissolution of tablets until they have moved from the stomach?
    enteric-coated fomrulations
  16. what two ways are routes of administration classified?
    • enteral
    • parenteral
  17. what type of drug is placed directly into the GI tract by oral or rectal administration?
  18. what is the safest, most common and convenient enteral route of administration?
  19. ____ _____ _____ may reduce concentration of drug molecules
    first pass effect
  20. what is it called when a drug is removed from the liver and has a low bioavailability?
    first pass
  21. _____ drugs bypass the GI tract and include various injectable routes
  22. what are five examples of parenteral drugs?
    • intravenous IV
    • subcutaneous SC
    • intramuscular IM
    • inhalation
    • topical routes
  23. what are two examples of topical routes of parenteral drugs?
    • sublingual
    • transdermal patch
  24. what are the 5 features of IV route?
    • bypasses absorption
    • most predictable route
    • used in emergency situations
    • less safe than oral route
    • injection site reactions possible
  25. drug distribution is achieved primarily through?
    the circulatory system
  26. which organs receive the drug minutes after absorption?
    • liver
    • kidney
    • heart
    • CNS
  27. what may affect the duration of a drug effect?
  28. what are four ways drugs are distributed?
    • redistribution
    • plasma protein
    • blood brain barrier
    • placenta as barrier
  29. t/f a bound drug to a plasma protein may cross the membrane
    false only a free or unbound drug is capable of crossing biologic membranes
  30. where does the majority of metabolism occur?
  31. why does metabolism happen most frequently in the liver?
    because it contains the greatest diversity and quantity of metabolic enzymes
  32. phase I and phase II are collectively referred to as what?
  33. what does biotransformation refer to?
    phase I and phase II processes
  34. what four ways can biotransformation alter drugs?
    • convert an active drug to an inactive drug
    • convert an active drug to an active or toxic metabolite
    • convert an inactive drug to an active drug
    • convert an unexcretable (more lipophilic) drug into an excretable (more hydrophilic) metabolite
  35. during phase I reactions a drugs chemical structure is modified through what?
    oxidation, reduction or hydrolysis
  36. what is the most commonly used pathway for phase I reactions
    hepatic microsomal cytochrome P450 (CYP450)
  37. during phase II reactions the chemical structure of a drug is modified how?
    by conjugation to a large polar endogenous molecule
  38. why is CYP450 induced or inhibited and what is it responsible for?
    • induced to increase drug metabolism
    • inhibited to reduce the rate of drugs metabolism
    • responsible for many adverse drug-drug interactions
  39. what is the most common means to eliminate drug molecules?
    renal excretion
  40. what is the most important mechanism of drug elimination from the body?
    renal excretion
  41. what two ways does glomerular filtration work?
    • active tubular secretion
    • passive tubular secretion
  42. what is the movement of drugs from the bloodstream into renal tubular fluid by a nonselective carrier system?
    active tubular secretion
  43. what is it called when drugs need to be retained by the body and the pH of the urine is manipulated?
    passive tubular reabsorption
  44. what is it called when metabolites in bile are hydrolyzed and reabsorbed from the gut and the drug action can be reestablished?
    enterophepatic recirculation
  45. what is exhalation used for during excretion?
    elimination of anesthetic gases and vapors
  46. what is the removal of most drugs from the body follows an exponential or first order kinetics (implies that a constnat fraction of the drug is eliminated per unit of time)
    half-life of a drug
  47. what is the plateau level of drug accumulates and involves over four half lives to eliminate the drug?
    steady state concentration
  48. how many half lives does it take to eliminate a drug from the body?