Principles of Pharmacology

Question 1

List 6 drugs which produce their effects due to their physicochemical properties.

Answer 1

Antacids
– sodium bicarbonate

Bulk laxatives
– methylcellulose

Osmotic laxatives
– magnesium sulfate

Osmotic diuretics
– mannitol

General anesthetics
– halothane

Alcohol

Question 2

Define potency.

Answer 2

The concentration of a drug required to produce a given proportion of its maximum effect.

Question 3

Define efficacy.

Answer 3

• The maximum response achievable.

- The capacity for sufficient therapeutic effect.

Question 4

Define affinity.

Answer 4

The binding strength of the drug receptor interaction.

Question 5

What type of ligand possesses affinity but not efficacy?

Answer 5

Antagonists.

Question 6

What type of ligand possesses both affinity and efficacy?

Answer 6

Agonists.

Question 7

What are the two assumptions made in quantitative pharmacology?

Answer 7

1 - The response is proportional to the concentration of drug-receptor complexes.

2 - There are a fixed number of receptors:
[Rt] = [R] + [AR]

Question 8

What is the equation for Kd?

Answer 8

[A] [R] / [AR]

Question 9

What is Kd a measure of?

Why?

Answer 9

Affinity.

Because it describes the concentration of agonist where the receptors are half-maximally saturated.

Question 10

What is EC50?

Answer 10

The concentration of agonist to produce the half maximal response.

Question 11

What is p?

What is the equation for p?

Answer 11

Fraction of occupancy.

p = [AR ] / [Rt]