Chapter 5 - Pharmacodynamics

Question 1

Pharmacodynamics

Answer 1

the study of what drugs do to the body and how they do it.

Question 2

Dose-response relationship

Answer 2

the relationship between the size of an administered dose and the intensity of the response produced

determines the minimum amount of drug needed to elicit a response, the maximum response a drug can elicit, and how much to increase the dosage to produce the desired increase in response.

Question 3

Dose-response curves reveal two characteristic properties of drugs:

Answer 3

maximal efficacy and relative potency.

Question 4

Maximal efficacy

Answer 4

the largest effect that a drug can produce.

Question 5

Maximal efficacy is indicated by the ____ of the dose-response curve

Answer 5

height

Question 6

What are the four primary families of receptors?

Answer 6

1. cell membrane–embedded enzymes
2. ligand-gated ion channels,
3. G protein–coupled receptor systems,
4. transcription factors

Question 7

Where is the ligand- binding domain located in Cell membrane- embedded enzymes?

Answer 7

cell surface, and the enzyme’s catalytic site is inside

Question 8

Cell Membrane–Embedded Enzymes

Answer 8

Binding of an endogenous regulatory molecule or agonist drug activates the enzyme, thereby increasing its catalytic activity ex insulin

Question 9

Ligand-Gated Ion Channels

Answer 9

The function of these receptors is to regulate flow of ions into and out of cells. GABA AND ACETYLCHOLINE

Like membrane-embedded enzymes, ligand-gated ion channels span the cell membrane

Question 10

G Protein–Coupled Receptor Systems

Answer 10

G protein–coupled receptor systems have three components: the receptor itself, G protein (so named because it binds guanosine triphosphate [GTP]), and an effector (typically an ion channel or an enzyme).

Question 11

Transcription factors

Answer 11

differ from other receptors in two ways: (1) transcription factors are found within the cell rather than on the surface, and (2) responses to activation of these receptors are delayed

Ex - Steriods and thyroid hormones

Question 12

What is the function of transcription factors?

Answer 12

regulate protein synthesis

Question 13

affinity

Answer 13

refers to the strength of the attraction between a drug and its receptor
** Drugs with high affinity are strongly attracted to their receptors **

Question 14

intrinsic activity

Answer 14

the ability of a drug to activate a receptor upon binding

Question 15

The intrinsic activity of a drug is reflected in its ________

Answer 15

maximal efficacy

Question 16

an antagonist is a drug with affinity for a receptor but with no ______

Answer 16

intrinsic activity

Question 17

A partial agonist is an agonist that has only moderate

Answer 17

intrinsic activity ex- Pentazocine(Talwin) a narcotic

Question 18

The therapeutic index is defined as ______

Answer 18

the ratio of a drug’s LD50 to its ED50.

Question 19

The therapeutic index is a measure of

Answer 19

a drug’s safety.

Question 20

The ED50 is defined as ____

Answer 20

the dose that is required to produce a defined therapeutic response in 50% of the population

Question 21

What are some examples of drugs that do not act of receptors?

Answer 21

antacids, antiseptics, saline laxatives, and chelating agents.

Question 22

Partial agonists are interesting in that they can act as

Answer 22

antagonists as well as agonists

Question 23

Competitive antagonists bind _____ to receptors

Answer 23

reversibily

Question 24

Noncompetitive antagonists bind _______ to receptors.

Answer 24

irreversibily