Module 1: Pharmacodyamics

Question 1

Define pharmacodynamics

Answer 1

What a drug does to the body (effects, mechanism of action)

Question 2

Define pharmacokinetics

Answer 2

How the body handles the drug (absorption, distribution, metabolism, excretion)

Question 3

What is an example of endogenous ligands?

Answer 3

Hormones or neurotransmitters

Question 3

Drugs are administered to achieve which two affects?

Answer 3

A beneficial response or a selective toxic effect

Question 4

What are four common types of receptors?

Answer 4

Regulatory proteins, transporters, enzymes, structural proteins

Question 4

What are the four common signalling mechanisms of regulatory proteins?

Answer 4

Ligand gated ion channels as receptors

G-protein coupled receptors

Intracellular receptors

Regulated Transmembrane Enzymes

Question 4

Briefly describe regulatory proteins

Answer 4

Proteins that mediate the actions of endogenous chemical signals.

Generally mediate transmembrane signalling

Question 5

What is the location of ligand gated ion channels?

Answer 5

Channels span across the cell membrane, with portions protruding out each side

Question 6

What do ligand gated ion channels transport?

Answer 6

Sodium, chloride, and other ions

Question 7

How does the ligand-gated ion channel open?

Answer 7

An endogenous ligand or drug binds to the receptor on the outside, causing a conformational change in the protein, opening it and allowing ions to flow through

Question 8

What is an example of a ligand gated ion channel?

Answer 8

Nicotinic receptors

Question 9

Where are G-protein coupled receptors located?

Answer 9

They span the outside to inside of the cell membrane

Question 10

How do G-protein coupled receptors activate?

Answer 10

A drug binds to the receptor on the outside of the cell membrane, a conformational change of the receptor protein occurs and activated the G-protein. The G-protein activates a number of second messenger systems that amplify the signal

Question 11

T/F - G-protein coupled receptors are a faster process than ligand-gated ion channels

Answer 11

False! G-protein coupled receptors are slower due to the activation of second messengers

Question 12

What activates G-protein coupled receptors?

Answer 12

Drugs, hormones, neurotransmitters, other signalling molecules

Question 13

What kinds of molecules activate intracellular receptors?

Answer 13

Lipid-soluble ones (including lipid soluble drugs), such as steroid hormones (cortisol) and thyroid hormones (Thyroxine)

Question 14

What affect does activating an intracellular receptor have on the cell?

Answer 14

Gene expression is modified and therefore subsequent protein synthesis (whether an increase or decrease)

Question 15

Why is the intracellular receptor process the slowest?

Answer 15

New proteins have to be synthesized and it takes time for those proteins to accumulate to produce an observed effect

Question 16

Describe where transmembrane enzymes are located

Answer 16

Located on the outside of the cell, but linked to an enzyme inside the cell

Question 17

How are regulated transmembrane enzymes activated?

Answer 17

When a drug binds to the extracellular receptor, the change in the receptor-drug complex allows for the activation of an enzyme that activates biochemical reactions to produce a biological effect

Question 18

Describe: non-competitive antagonist

Answer 18

Binds irreversibly to a receptor but does not activate it. Causes a conformational change of the receptor, inhibiting an agonist from binding

Question 18

Describe: Competitive antagonist

Answer 18

Bind to the same spot on the receptor as the agonist, but does not produce a response. Does not allow for agonists to bind

Question 18

Protein kinases are which type of enzyme?

Answer 18

Regulated transmembrane enzymes

Question 18

Describe: Partial agonist

Answer 18

Bind to the receptor and activate it, but produce a weaker response

Question 18

T/F - All drugs are mediated by receptors

Answer 18

False. Some drugs interact non-specifically with the biological system.

Ex., antacids use an acid-base neutralization reaction
Ex., Some chemotherapy drugs chemically disrupt cancer cell function

Question 18

Describe: Agonist

Answer 18

Agonist bind to the receptors and activate it

Question 18

Describe: Allosteric activator

Answer 18

Binds to a different area of the receptor than the agonist, but makes it easier for the receptor to be activated. Increases the ability of an agonist to activate a receptor

Question 19

What is the graded dose response relationship?

Answer 19

Describes a drug effect which increases in proportion to increasing the drug dose

Question 19

Why does the inhibition from a non-competitive antagonist more permanent than that of a competitive antagonist

Answer 19

Because non-competitive antagonists cause a conformational change instead of just fighting for the receptor site, increasing the concentration of agonist does not overcome the inhibition

Question 19

What is the ED50?

Answer 19

The dose of a drug that will result in 50% of the maximal effect, or the dose of a drug that is effective in 50% of a population

Question 20

What is the receptor threshold?

Answer 20

The minimum number of receptors that need to be activated to observe a measurable response

Question 21

T/F - The dose is proportional to the effect only after the receptor threshold has been reached

Answer 21

True!

Question 22

Describe the maximal response

Answer 22

The response where further increases in dose will no longer correspond to increases in therapeutic effect

Question 23

Will an agonist, partial agonist, or allosteric activator plus an agonist have the greatest maximal effect?

Answer 23

An allosteric activator plus an agonist, followed by the agonist, followed by the partial agonist

Question 24

Define efficacy

Answer 24

The maximum pharmacological response that can be produced by a specific drug in that biological system

Question 25

Define potency

Answer 25

The dose or concentration of a drug that is required to produce a response of a certain magnitude - usually 50% of the maximal response

Question 26

Drug A produces a response at 40mg, Drug B produces the same response at 20mg. Is drug B more efficacious or more potent?

Answer 26

Drug B is more potent, as it is producing the same response, but at a lower dose

Question 27

Drug A can treat pain patients say is a 10/10. Drug B can treat pain that is described as a 3/10. Is Drug A more efficacious or potent?

Answer 27

Drug A is more efficacious. It can produce a greater maximum effect.

Question 27

T/F - Clinically, efficacy is more important than potency

Answer 27

True! Maximal effectiveness of a drug is generally what determines which drug is chosen to treat a condition. The potency doesn’t matter as much, as doses can be adjusted

Question 28

Describe the therapeutic range

Answer 28

The range of drug concentration in the plasma that is above the minimum concentration to produce a response, but below toxic concentrations