Basic Pharmacology- How do drugs work?

Question 1

What is an antagonist?

Answer 1

• Disrupts agonist activity which reduces excess

Question 2

What are the 4 types of antagonist?

Answer 2

• Competitive Antagonist
• Non-competitive Antagonist
• Pharmacokinetic
• Physiological

Question 3

What is a competitive antagonist?

Answer 3

• Reversible
• No direct effect but competes with agonist for the active site
• Increase in agonist can surmount the antagonist
• Reduces agonist’s ability to produce a response

Question 4

What is a non-competitive antagonist?

Answer 4

• May occupy receptors irreversibly (or dissociate very slowly)
• Some non-competitive antagonists may bind elsewhere on receptor which allosterically changes conformation preventing against binding
• Insurmountable blocks a fraction of receptors

Question 5

What do we mean by the term ‘spare receptors’?

Answer 5

• Many agonists can produce a maximum response with partial activation
• Not all receptors require activation

Question 6

What do we mean by the term ‘partial agonists’?

Answer 6

• Cannot reach full response even with full activation

- In the presence of a full agonist, a partial agonist becomes a partial antagonist

Question 7

What is tolerance?

Answer 7

Slow declining response to repeat administration

Question 8

What is tachyphylaxis?

Answer 8

Fast declining response to repeat administration