Pharmacodynamics I

Question 1

What does it mean that a drug response is graded?

Answer 1

increasing the dose increases the response (usually non-linearly), up to some maximal point

Question 2

does drug displacement occur in drug receptor interactions?

Answer 2

no

Question 3

What is receptor fractional occupancy independent of?

Answer 3

receptor density

Question 4

What is receptor fractional occupancy dependent on?

Answer 4

drug affinity (Kd)

Drug concentration

Question 5

How are drug affinity and Kd values related?

Answer 5

inversely

Question 6

What is Kd?

Answer 6

The Affinity Constant (i.e., the KD) of a drug represents the concentration of that drug required to occupy 50% of a receptor population.

Question 7

As dose is increased, what will happen to the selectivity?

Answer 7

It will decrease

Question 8

What is potency?

Answer 8

refers to the concentration or dose of drug needed to produce 50% of that drug’s maximal response (EC50 or ED50 value).

Question 9

What does potency depend on?

Answer 9

its affinity for the receptor & the efficiency with which the receptor activation is coupled to response

Question 10

What is maximal efficacy (intrinsic activity)?

Answer 10

the maximal response produced by the drug

Question 11

What does the clinical effectiveness of a drug depend on?

Answer 11

it’s maximal efficacy (Emax) - NOT the potency (ED50)

Question 12

What can be detwermined from quantal dose-response curves?

Answer 12

The Median Effective Dose (ED50)

n index of selectivity of a drugs actions by comparing its ED50 for different specified effects

An estimate of the degree of Safety for a Drug for a Specified Effect

Question 13

What is the therapeutic window?

Answer 13

This is the Dosage Range between the minimum effective therapeutic dose and the minimum toxic dose

Question 14

What is a better measure of drug safety?

Answer 14

Drug safety can be better assessed from the Therapeutic Window than from the Therapeutic Index