Principles of Pharmacology

Question 1

Define pharmacology

Answer 1

The study of the mechanism of drug action

Question 2

Define drug in two parts

Answer 2

• the active ingredient of a medicine

- any substance which interacts with a biological system and changes it

Question 3

How many names are there for every drug?

Answer 3

• chemical name e.g. acetylsalicylic acid
• generic name e.g. aspirin
• trade name e.g. aspro, disprin, anadin etc.

Question 4

Examples of drugs which produce their effects due to their physicochemical properties x6
Facts about these types of drugs x2

Answer 4

antacids
bulk laxatives
osmotic laxatives
osmotic diuretics
general anaesthetics
alcohol

Tend to need high cons
Effects are rather non specific

Question 5

Define potency

Answer 5

The ability of a drug to produce an effect of known intensity

Question 6

What is the difference between chemical and biological specificity?

Answer 6

Bio - due to receptors, same drug can have different effect on different tissues
Chem - changing the molecular structure can have high effect of activity of drug

Question 7

What is the receptor concept?

Answer 7

• drugs produce their effects by combining with specific receptor sites in cells
• the response is a function of the number of occupied receptors

Question 8

Define affinity

Answer 8

The ‘strength’ of the drug receptor interaction.

Drugs with high affinity are more potent

Question 9

Define agonist
…in terms of efficacy and affinity
Example

Answer 9

Binds to a receptor and produces a response
Possesses affinity and efficacy
e.g. ACh

Question 10

Define antagonist
…in terms of efficacy and affinity
Example

Answer 10

Binds to a receptor but does not produce a response
Possesses affinity but not efficacy
e.g. atropine, prevents ACh from binding

Question 11

The relationship between drug concentration and response. what 3 things is it?
What does graph look like?

Answer 11

• graded (not all or nothing)
• saturating
• exhibits threshold
• sigmoidal when log(cons)
• hyperbolic when conc

Question 12

What is the law of mass action?

What is p?

Answer 12

The rate of the chemical reaction is directly proportional to the masses of the reactant concentrations.
p = occupancy, the number of drug-receptor complexes formed over the total number of receptors present.