Exam 2 - Rush University (Questions
& Answers)
1. Pharmacodynamics:: what the drug does to the body X5 X5 X5 X5 X5 X5 X5
2. What is an LDR curve?: A log dose response curve, or a curve that describes the
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relationship bewteen the drug effect (Y axis) and the log of the dose (X axis).
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3. What is the difference between quantal and graded LDR curves?: Graded:
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the effectof the drug falls on a scale (i.e.howmanymmHGdid the BP decline when
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plotted against an increasing log dose?)
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Quantal:the "response" is predefined (i.e.a SBP < 130 mmHg) and data is plotted to
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show who was affected and who wasn't. an either/or situation.
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4. Potency: The dose of a drug necessary to produce 50% of a drug's maximal
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effect (ED50).Sort of tells you "how much bang you get for your buck" in terms of
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solely dosage amount.
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5. If the maximal response to a new medication is a 50mmHg decline in SBP,
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what is the ED50 on a graded LDR curve?: The dosage that will produce a
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25mmHg declined in SBP.
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6. If the desired response for a new medication is a decrease in SBP to < 130
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mmHg, what is the ED50 on a quantal LDR curve?: The dosage associated with
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reaching the target BP (< 130) in 50% of the population.
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,7. Efficacy: The maximum response that a drug is capable of producing.X5 X5 X5 X5 X5 X5 X5 X5 X5 X5
8. Compare each drug's potency and efficacy: X5 X5 X5 X5 X5
9. What does the steepness of an LDR curve indicate?: What degree of effect a
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dose change will have (slight change on a steep curve will elicit large effects, big
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change on a flat curve will elicit small effects).
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10. ED50: The dose of a medication that produces a specific therapeutic effect in
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50% of the population.
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11. TD50: The dose of a medication that produces a specific toxic effect in 50% of the
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population.
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12. Therapeutic index: TD50/ED50,or the space between the therapeuticand toxic X5 X5 X5 X5 X5 X5 X5 X5 X5 X5
LDR curves of a drug.
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13. True or false: a drug with a wide therapeutic index is generally safer than a
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drug with a narrow therapeutic index.: True
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14. Calculate the therapeutic index of a drug if the ED50 = 0.4 and theTD50 = 40.: X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X
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40/0.4 = 100
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15. True or false: you can visually compare the therapeutic indexes, and safety, of
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two drugs with different slopes.: False - if the two drugs have curves that are not
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parallel to each other they are not easily compared.
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16. Stereoisomer: A drug that has both an active and inactive isomer, formulated so X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X5 X5
that the active isomer is at a dose that achieves the therapeutic response.
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17. Enantiomers: Mirror image stereoisomers (have the same chemical structure X5 X5 X5 X5 X5 X5 X5 X5
with a different orientation) that have different pharmacological effects.
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, 18. Racemic mixture: An equal mixture of two enantiomers.Ex:Albuterol, consist- ing X5j X5j X5j X5j X5j X5j X5j X
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of the active isomer (R-albuterol) and an inactive isomer (S-albuterol). Effects from
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the inactive isomer are usually clinically insignificant.
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19. Ka: The volume needed togetonemole ofunbounddrugwhen 50%ofthe target
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receptors are occupied.
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20. Kd: The concentration of drug in the plasma when 50% of the target receptors
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are occupied
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21. Partialagonist: Adrugthatbindstoareceptorandstimulatesaneffectthathas bothX
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lower potency (curve is shifted right of the full agonist) and efficacy (curve is shorter
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in height).
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22. Why would we give a partial agonist?:To prevent undesirable side effects of the
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full agonist, or because the full agonist isn't necessary. Ex: greater pain relief and
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psychotropic effects from methadone, but less respiratory depression from
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buprenorphine.
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23. Competitive antagonism:Reversible;effects depend on the relative concen- X5j X
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tration of the agonist and antagonists (which also occupy receptor sites)
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24. What will the LDR curve of an agonist combined with a fixed dose of a
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competitive antagonist look like?: Parallel to the agonist curve, but shifted to
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the right.Effects of the antagonist can be overcome with an increased dose of the
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agonist.
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25. Noncompetitive antagonism: Irreversible;effects are independent of the rela- X5j Xj5 X
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tive concentration of the agonist and antagonist (which don't occupy the agonists'
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receptor sites).
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26. What will the LDR curve of an agonist combined with a fixed dose of a
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noncompetitive antagonist look like?: Shifted downward and to the right.Effects of
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the antagonist cannot be overcome with an increased dose of the agonist.
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27. What is the clinical relevance of giving an irreversible, non-competitive
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antagonist?: Mustwaitfortheeffectsoftheantagonisttowearoff,sincegivingmore
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agonist will have no effect (ex: pt stops taking aspirin 10-14 days prior to surgery).
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28. What type of antagonist drug do we most often administer?: Reversible,
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competitive antagonists (much easier to control).
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29. True or false: no matter how high the molar concentration of a reversible,
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