Pharm 3 - Drug-Receptor Interaction

Question 1

Define Pharmacokinetics.

Answer 1

The effect the body has on the drug

Question 2

Define Pharmacodynamic.

Answer 2

The effect of the drug on the body

Question 3

Define ‘drug’.

Answer 3

a chemical substance that interacts with a bioloigcal system to produce a physiological response

Question 4

State the 4 main target sites for drugs.

Answer 4

Receptors
Enzymes
Ion Channels
Transport Systems

Question 5

What are the two types of ion channels?

Answer 5

Voltage gated

Receptor linked

Question 6

Give an example of a drug that acts on an ion channel.

Answer 6

Local anaesthetics - block the voltage gates sodium channels of nociceptors to prevent conduction of pain signals

Question 7

Give an example of a group of drugs that act on transport systems.

Answer 7

cardiac glycosides - slows down Na+/K+ pump so more intracellular calcium so increased force of contraction

Question 8

What are the 3 ways drugs can interact with enzymes?

Answer 8

Enzyme inhibitors
False Transmitters
Prodrugs

Question 9

Name a common example of an unwanted effect of a drug interaction with an enzyme.

Answer 9

Paracetamol overdose
saturates the microsomal enzymes of the liver

so CP450 breaks it down to form toxic metabolites

Question 10

Name 3 groups of drugs that are exceptions to the 4 target site rule.

Answer 10

General anaesthetics
Antacids
Osmotic purgatives

Question 11

Define agonist.

Answer 11

a molecule that binds to a receptor and generates a response

Question 12

Define antagonist.

Answer 12

a molecule that binds to a receptor but does not generate a response

Question 13

Define potency.

Answer 13

How powerful a drug is.

Question 14

What two things is potency dependent on?

Answer 14

affinity and efficacy

Question 15

Define affinity and efficacy.

Answer 15

Affinity - how willingly the drug binds to the receptor

Efficacy - the ability of the drug to generate a response once bound.

Question 16

What is a full agonist?

Answer 16

agonist that generates a maximum response

partial agonist generates less than max response

Question 17

What is selectivity?

Answer 17

drugs have a preference for binding to certain receptors

Question 18

What is the difference between full agonists with high affinity and full agonists with a lower affinity?

Answer 18

Full agonists with a lower affinity can still generate a max response but require a larger dose

Question 19

Describe antagonists in terms of affinity and efficacy.

Answer 19

Have affinity but no efficacy.

Question 20

What are the two types of antagonists?

Answer 20

Competitive - surmountable

Irreversible - insurmountable

Question 21

What affect do competitive antagonists have on dose response curves?

Answer 21

Shifts curve to right

just need more of the agonist to work

Question 22

What effect do irreversible antagonists have on the dose response curve?

Answer 22

Right and Down

can no longer generate max response as you have knocked out some of the receptors

Question 23

What is receptor reserve?

Answer 23

not all the receptors need to be stimulated to generate a max response

Question 24

True or False: full agonists that are selective for a given receptor will have the same efficacy

Answer 24

True

full agonists elicit a maximum response