GU Pharm Exam 1 Module 1

  1. ED 50
    Dosage at which 50% of people have therapeutic effect
  2. TD 50
    Dosage at which 50 % of people have toxicity
  3. LD 50
    Dosage at which 50% of people die/lethal effect
  4. Define the "therapeutic window"
    Efficacy without unacceptable toxicity
  5. Equation for the Therapeutic Index
    TI= TD50/ ED50
  6. High TI
    wide therapeutic window
  7. Low TI
    small therapeutic window
  8. D+ R = DR
    What is DR?
    DR= drug-receptor binding without effect
  9. D + R = DR*
    What is DR*
    drug binding with response
  10. What does a FULL AGONIST do?
    • 1. elicits maximal response
    • 2. Stabilizes DR*
  11. What does a PARTIAL AGONIST/Mixed agonist-antagonist do?
    • Activates receptor but not with maximal efficacy
    • Stabilizes DR and DR*
  12. What does an INVERSE AGONIST do?
    • 1. Inactivates free active receptors
    • 2. Stabilizes DR in the case of R*(natural form)
  13. What does an ANTAGONIST do?
    1. Stabilization of DR; prevention of DR*
  14. What does a competitive antagonist do?
    • 1. Has reversible binding at active site
    • 2. Competes with agonist binding to site
  15. What does non-competitive active site antagonist do?
    • 1. Has irreversible active site binding
    • 2. No DR*- prevents agonist binding to site
  16. Name two types of non-receptor antagonists?
    Give an example of each?
    • Chemical- agonist inactivation (PROTAMINE)
    • Physiologic- mediates opposite response of agonist  (B-blocker to reverse tachycardia in hyperthyroidism)
  17. What is the allosteric site?
    Binding site other than the drug/enzyme's active site
  18. What does a non-competitive allosteric antagonist do?
    • 1. Binds reversibly or irreversibly to allosteric site
    • 2. Prevents conformational change required for receptor activation
  19. What is pharmacodynamics?
    Name 3 factors that affect PD
    • What the drug does to the body
    • 1. drug-receptor interaction
    • 2. patient's functional state
    • 3. placebo effects
  20. What is pharmacokinetics?
    What are the 4 principles of PK
    • What the body does to the drug.
    • 1. Absorption
    • 2. Distribution
    • 3. Metabolism
    • 4. Elimination
  21. Are non-ionized molecules more or less readily absorbed by the body?
    • More readily absorbed.
    • Ionized molecules are hydrophilic and have difficulty penetrating membranes
  22. What is the pka?
    pH at which 50% of the drug is ionized.
  23. What is pH trapping?
    Once a drug is ionized in the plasma- the drug is trapped and will not return to the GI system.

    Determined by the pka and pH gradient across the membrane
  24. Name the 4 types of DR bonds and their relative strength.
    • 1. van der Waals: shifting electrons, transient + and - charges; weakest
    • 2. Hydrogen: H atoms bound to nitrogen or O2..
    • 3. Ionic: Atoms with excess of electrons attracted to + atoms = net positive
    • 4. Covalent: Two bonding atoms share an electron. Strongest
  25. Nonionized molecules are __________
    Ionized molecules are ___________
    • lipophilic (lipid soluble) (HA)
    • hydrophillic (difficulty penetrating lipid membranes)
  26. What are factors that affect drug absorption?
    Whether po, IV or transdermal admin
    1. concentration (↑ concentration, ↑ absorption)

    • 2. Circulation at site of admin (↑ circ, ↑ absorption)
    • 3. Drug solubility
    • 4. Surface area
  27. What factors affect drug distribution?
    • 1. BMI
    • 2. Age (elderly-low, infants-high)
    • 3. Protein binding (highly bound drugs stay in the plasma longer)
    • 4. Hydration
  28. What is First Pass Metabolism?
    • Portion of the drug is lost in liver metabolism and not bioavailable to plasma.
    • Primarily po drugs have first-pass effects.
  29. Name three possible CYP450 interactions and their possible results
    • 1. competition (toxicity is possible due to increased metabolism)
    • 2. induction (lower concentrations, need to give more drug in order to have effect)
    • 3. Inhibition (drug cannot be broken down, levels elevate)
  30. True or false:
    Nonionized, lipophilic drugs are favored for oral absorption.
  31. CYP450 inhibitors will _________ the drug effect. Example of two CYP Drug inhibitors:
    Slow down substrate drug metabolism and increase drug effect.

    Amiodarone and Warfarin leading to increased bleeding risk
  32. CYP 450 inducer will ___________ drug effect
    These will speed up substrate drug metabolism and decrease drug effect.

    • 1. increase transcription or translation
    • 2. decrease degredation
    • 3. induction by another drug or autoinduction
  33. Name some disadvantages of PO administration of drugs
    1. Absorption challenges: harsh GI enviroment, slow delivery, First pass metabolism
  34. Which types of drugs are favored for PO admin?
    • 1. non-ionized, lipophilic drugs
    • 2. weak acids for absoprtion from stomach
    • 3. weak bases for absorption from sm intestines
  35. Facts about rectal administration
    • 1. when oral admin isn't possible
    • 2. 50% of drug will bypass liver (1st pass)
    • 3. Erratic absorption
    • 4. Irritation of the rectal mucosa
  36. Transdermally absorbed drugs need to have ____________________
    high lipophilicity
  37. Advantages of transdermal admin.....
    • No hepatic first pass
    • No harsh GI environment
    • COntinuous admin (slow release) makes stead state easier to achieve
  38. Low Vd drugs ___________within the plasma/vascular space
    are retained
  39. High Vd drugs ____________ in the vascular space
    do not stay (are poorly concentrated)
  40. High Vd drugs are __________distributed in the the tissue
  41. Low Vd drugs are ___________ in the tissue/non-vascular compartments
    poorly distributed
  42. For drugs to be metabolized they must be _______ in plasma. Drugs that are _________ cannot readily be metabolized.
    • unbound
    • highly protein-bound
  43. Name the 2 biotransformation reactions.
    • 1. Phase I= oxidation/reduction
    • 2. Phase II=conjugation/hydrolysis
  44. 3 most important parameters for accessible concentration of drugs
    • 1. clearance (metabolism and excretion)
    • 2. Vd (apparent space in the body)
    • 3. Bioavailability (the fraction of drug absorbed into systemic circulation
  45. Equation for drug clearance (CL)
    CL=(metabolism + excretion)/Drug-plasma
  46. What is first order kinetics?
    1. Increase in plasma concentration = matched increase in clearance
  47. What is zero order kinetics?
    Increase in plasma concentration with no increase in clearance b/c the enzymes that metabolize the drugs become saturated...
  48. What is T1/2?
    half-life is the time it takes for the plasma concentration to be reduced by 50%
  49. What is the formula for half-life T1/2
    T1/2=0.693/k and k=elimination rate constant
  50. What is the Cmax?
    peak plasma concentration
  51. What is the Cmin?
    min plasma concentration
  52. If the Vd of drug is low, you need to give ____(dosage of drug).
  53. Generally, it takes about ____ half-lifes for a drug to reach steady state and ____ half-lifes for it to be eliminated.
    • 5
    • 5
  54. What is a pharmacokinetic drug interaction?
    When a drug inhibits metabolism of another drug.....leading to toxicity
  55. What is a pharmacodynamic drug-drug interaction?
    Drug causes another drug to work more at a certain receptor but not r/t concentration of the drug.
Card Set
GU Pharm Exam 1 Module 1
Exam 1