NSG 533 ADVANCED PHARMACOLOGY EXAM QUESTIONS
AND ANSWERS LATEST UPDATE
Pharmacodynamics:
what the drug does to the body
What is an LDR curve?
A log dose response curve, or a curve that describes the relationship bewteen the drug
effect (Y axis) and the log of the dose (X axis).
What is the difference between quantal and graded LDR curves?
Graded: the effect of the drug falls on a scale (i.e. how many mmHG did the BP decline
when plotted against an increasing log dose?)
Quantal: the "response" is predefined (i.e. a SBP < 130 mmHg) and data is plotted to
show who was affected and who wasn't. an either/or situation.
Potency
The dose of a drug necessary to produce 50% of a drug's maximal effect (ED50). Sort
of tells you "how much bang you get for your buck" in terms of solely dosage amount.
If the maximal response to a new medication is a 50mmHg decline in SBP, what is
the ED50 on a graded LDR curve?
The dosage that will produce a 25mmHg declined in SBP.
If the desired response for a new medication is a decrease in SBP to < 130 mmHg,
what is the ED50 on a quantal LDR curve?
The dosage associated with reaching the target BP (< 130) in 50% of the population.
Efficacy
The maximum response that a drug is capable of producing.
Compare each drug's potency and efficacy
What does the steepness of an LDR curve indicate?
What degree of effect a dose change will have (slight change on a steep curve will elicit
large effects, big change on a flat curve will elicit small effects).
ED50
The dose of a medication that produces a specific therapeutic effect in 50% of the
population.
TD50
, The dose of a medication that produces a specific toxic effect in 50% of the population.
Therapeutic index
TD50/ED50, or the space between the therapeutic and toxic LDR curves of a drug.
True or false: a drug with a wide therapeutic index is generally safer than a drug
with a narrow therapeutic index.
True
Calculate the therapeutic index of a drug if the ED50 = 0.4 and the TD50 = 40.
40/0.4 = 100
True or false: you can visually compare the therapeutic indexes, and safety, of
two drugs with different slopes.
False - if the two drugs have curves that are not parallel to each other they are not
easily compared.
Stereoisomer
A drug that has both an active and inactive isomer, formulated so that the active isomer
is at a dose that achieves the therapeutic response.
Enantiomers
Mirror image stereoisomers (have the same chemical structure with a different
orientation) that have different pharmacological effects.
Racemic mixture
An equal mixture of two enantiomers. Ex: Albuterol, consisting of the active isomer (R-
albuterol) and an inactive isomer (S-albuterol). Effects from the inactive isomer are
usually clinically insignificant.
Ka
The volume needed to get one mole of unbound drug when 50% of the target receptors
are occupied.
Kd
The concentration of drug in the plasma when 50% of the target receptors are occupied
Partial agonist
A drug that binds to a receptor and stimulates an effect that has both lower potency
(curve is shifted right of the full agonist) and efficacy (curve is shorter in height).
Why would we give a partial agonist?
AND ANSWERS LATEST UPDATE
Pharmacodynamics:
what the drug does to the body
What is an LDR curve?
A log dose response curve, or a curve that describes the relationship bewteen the drug
effect (Y axis) and the log of the dose (X axis).
What is the difference between quantal and graded LDR curves?
Graded: the effect of the drug falls on a scale (i.e. how many mmHG did the BP decline
when plotted against an increasing log dose?)
Quantal: the "response" is predefined (i.e. a SBP < 130 mmHg) and data is plotted to
show who was affected and who wasn't. an either/or situation.
Potency
The dose of a drug necessary to produce 50% of a drug's maximal effect (ED50). Sort
of tells you "how much bang you get for your buck" in terms of solely dosage amount.
If the maximal response to a new medication is a 50mmHg decline in SBP, what is
the ED50 on a graded LDR curve?
The dosage that will produce a 25mmHg declined in SBP.
If the desired response for a new medication is a decrease in SBP to < 130 mmHg,
what is the ED50 on a quantal LDR curve?
The dosage associated with reaching the target BP (< 130) in 50% of the population.
Efficacy
The maximum response that a drug is capable of producing.
Compare each drug's potency and efficacy
What does the steepness of an LDR curve indicate?
What degree of effect a dose change will have (slight change on a steep curve will elicit
large effects, big change on a flat curve will elicit small effects).
ED50
The dose of a medication that produces a specific therapeutic effect in 50% of the
population.
TD50
, The dose of a medication that produces a specific toxic effect in 50% of the population.
Therapeutic index
TD50/ED50, or the space between the therapeutic and toxic LDR curves of a drug.
True or false: a drug with a wide therapeutic index is generally safer than a drug
with a narrow therapeutic index.
True
Calculate the therapeutic index of a drug if the ED50 = 0.4 and the TD50 = 40.
40/0.4 = 100
True or false: you can visually compare the therapeutic indexes, and safety, of
two drugs with different slopes.
False - if the two drugs have curves that are not parallel to each other they are not
easily compared.
Stereoisomer
A drug that has both an active and inactive isomer, formulated so that the active isomer
is at a dose that achieves the therapeutic response.
Enantiomers
Mirror image stereoisomers (have the same chemical structure with a different
orientation) that have different pharmacological effects.
Racemic mixture
An equal mixture of two enantiomers. Ex: Albuterol, consisting of the active isomer (R-
albuterol) and an inactive isomer (S-albuterol). Effects from the inactive isomer are
usually clinically insignificant.
Ka
The volume needed to get one mole of unbound drug when 50% of the target receptors
are occupied.
Kd
The concentration of drug in the plasma when 50% of the target receptors are occupied
Partial agonist
A drug that binds to a receptor and stimulates an effect that has both lower potency
(curve is shifted right of the full agonist) and efficacy (curve is shorter in height).
Why would we give a partial agonist?
