Lehne: Pharmacology Adn1 Test 3-Chapter-5-Pharmacodynamics

Front 1

• Pharmacodynamics is the study of:

Back 1

the biochemical and physiologic effects of drugs and the molecular mechanisms by which those effects are produced.

Front 2

• For most drugs, the dose-response relationship is graded. This means:

Back 2

the response gets more intense with increasing dosage.

Front 3

• Maximal efficacy is defined as:

Back 3

the biggest effect a drug can produce.

Front 4

• Although efficacy is important, there are many situations in which a drug with relatively low efficacy is:

Back 4

preferable to a drug with very high efficacy.

Front 5

• A potent drug is simply a drug that:

Back 5

produces its effects at low doses. As a rule, potency is not important

Front 6

• Potency and efficacy are independent qualities.

Back 6

Drug A can be more effective than drug B even though drug B may be more potent. Also, drugs A and B can be equally effective, although one may be more potent than the other.

Front 7

• A receptor can be defined as:

Back 7

any functional macromolecule in a cell to which a drug binds to produce its effects

Front 8

• Binding of drugs to their receptors is:

Back 8

almost always reversible

Front 9

• The receptors through which drugs act are:

Back 9

normal points of control for physiologic processes.
Under physiologic conditions, receptor function is regulated by molecules supplied by the body

Front 10

• All that drugs can do at receptors is:

Back 10

mimic or block the action of the body’s own regulatory molecules

Front 11

• Because drug action is limited to:

Back 11

mimicking or blocking the body’s own regulatory molecules, drugs cannot give cells new functions.
Rather, drugs can only alter the rate of pre-existing processes

Front 12

There are four primary families of receptors:

Back 12

cell membrane-embedded enzymes, ligand-gated ion channels,
G protein-coupled receptor systems, and transcription factors

Front 13

• Receptors make selective drug action possible, therefore:

Back 13

If a drug interacts with only one type of receptor, and if that receptor type regulates just a few processes, then the effects of the drug will be relatively selective.

Front 14

• If a drug interacts with only one type of receptor, but that receptor type regulates multiple processes, then:

Back 14

the effects of the drug will be nonselective

Front 15

If a drug interacts with multiple receptors

Back 15

its effects will be nonselective.

Front 16

Selectivity does not guarantee:

Back 16

safety.

Front 17

The term affinity refers to :

Back 17

the strength of the attraction between a drug and its receptor

Front 18

• Drugs with high affinity have:

Back 18

high relative potency.

Front 19

• The term intrinsic activity refers to:

Back 19

the ability of a drug to activate receptors.

Front 20

• Drugs with high intrinsic activity have:

Back 20

high maximal efficacy.

Front 21

• Agonists are:

Back 21

molecules that activate receptors

Front 22

• In terms of the modified occupancy theory, agonists have:

Back 22

both affinity and high intrinsic activity. Affinity allows them to bind to receptors, whereas intrinsic activity allows them to activate the receptor after binding.

Front 23

• Antagonists are drugs that:

Back 23

prevent receptor activation by endogenous regulatory molecules and by other drugs.

Front 24

• Antagonists can be subdivided into two major classes:

Back 24

(1) noncompetitive antagonists and
(2) competitive antagonists.

Most antagonists are competitive.

Front 25

• Noncompetitive antagonists bind:

Back 25

irreversibly to receptors.

Front 26

• Competitive antagonists bind:

Back 26

reversibly to receptors.

Front 27

• In terms of the modified occupancy theory, antagonists have:

Back 27

affinity for receptors but no intrinsic activity. Affinity allows the antagonist to bind to receptors, but lack of intrinsic activity prevents the bound antagonist from causing receptor activation.

Front 28

• Antagonists have no observable effects in the absence of:

Back 28

agonists.

Front 29

• Partial agonists have only moderate:

Back 29

intrinsic activity.
Hence their maximal efficacy is lower than that of full agonists.

Front 30

• Partial agonists can act as agonists if

Back 30

there is no full agonist present

Front 31

Partial agonists can act as antagonists if:

Back 31

a full agonist is present.

Front 32

• Continuous exposure of cells to agonists can result in:

Back 32

receptor desensitization (aka refractoriness or down-regulation).

Front 33

continuous exposure of cells to antagonists can result in:

Back 33

hypersensitivity (aka supersensitivity).

Front 34

• The ED50 is defined as:

Back 34

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

Front 35

• An average effective dose (ED50) is perfect for some people, insufficient for others, and excessive for still others.:

Back 35

Because drug responses are not completely predictable, you must look at the patient (and not some drug reference book) to determine if dosage is appropriate.

Front 36

• The therapeutic index—defined as the LD50:ED50 ratio—is:

Back 36

a measure of a drug’s safety.
Drugs with a high therapeutic index are safe. Drugs with a low therapeutic index are not safe.

Front 37

• Because of variability in responses, nurses, patients, and other concerned individuals must evaluate:

Back 37

actual responses and be prepared to inform the prescriber about these responses so that proper adjustments in dosage can be made.