Topic 6 - Competition

Question 1

Competition Dynamic

Agonist Kd=Antagonist Kd

Answer 1

Both will occupy the same proportion of receptors

If agonist bounded to 50% of all receptors it now binds to 33%
As antagonist is also now taking up 50% of all available receptors

Question 2

Competition Dynamic

Agonist Kd<Antagonist Kd

Antagonist concentration = Kd

Answer 2

Both will occupy the same proportion of receptors

Antagonist is at its Kd concentration so will only occupy 50% of all available receptors

Question 3

Competition Dynamic

Agonist Kd<Antagonist Kd

Antagonist concentration is double than its Kd

Answer 3

Agonist will take up 50% of all available receptors
However, antagonist will take up most of all available receptors

Question 4

Endogenous Receptor Agonist + Drug

Answer 4

Agonist has reduced binding as drug competes with it

Can increase / decrease receptor activation

Question 5

Transporter Substrate + Transporter Inhibitor Drug

Answer 5

Reduced transport of the substrate as transporter is either occupied with drug or is inactive

Question 6

Enzyme Substrate + Drug

Answer 6

Substrate concentrations are increased

Question 7

Drug + Drug (Plasma Proteins)

Answer 7

Drugs compete with each other for binding with plasma proteins

Increase plasma concentrations – > Increased side effects

Question 8

Drug + Drug (Drug Metabolizing Enzymes)

Answer 8

The peak of both drugs is increased as the enzymes are occupied with the numerous drugs –> Slows down removal

Question 9

Drug + Drug (Renal Transporters)

Answer 9

Slows renal clearance of both drug, drugs stay in system longer