Pharmacodynamics

Question 1

Describe the basic drug-receptor theory

Answer 1

Agonist drug binds to receptor = Activation = Response

Measure response via organ bath simulation at contraction/relaxation of tissue

Question 2

Define affinity (KD)

Answer 2

Tendency for ligand to form stable complex with receptor

Governed by bonds and shape of ligand

Question 3

Define an agonist and its two components

Answer 3

A drug that binds to receptors to produce a response

1. Binds to occupy a receptor (Affinity)
2. Produces a response (efficacy)

Question 4

Define Bmax

Answer 4

Maximum number of binding sites, Measures saturation

Question 5

Define Dissociated constant, Kd (M)

Answer 5

Affinity of binding (how well drug binds to receptor)

Question 6

Is a higher or lower Kd better and why?

Answer 6

Lower Kd = Means it has highest affinity to fully bind at lowest conc

Question 7

Define an antagonist

Answer 7

The drug that binds to a receptor without mediating a response but blocks agonist response

Question 8

What are the 5 types of antagonism?

Answer 8

Competitive antagonism (reversible/irreversible) receptor effector block (non-comp), chemical, pharmacokinetic, physiological antagonism

Question 9

Describe non competitive antagonism

Answer 9

Blocks receptor activation and response, doesn’t compete for receptor site

Question 10

Describe chemical antagonism and an example

Answer 10

2 substances combine in solution, effect of active drug is lost
Eg chelating agents that bind to heavy metals reduce toxicity