Lehne Book: Chapter 5 - Pharmacodynamics

Question 1

The study of the biochemical and physiologic effects of drugs and the molecular mechanisms by which those effects are produced. Simply put, the study of what drugs do to the body and how they do it.

Answer 1

Pharmacodynamics

Question 2

____-_____ ______ is the relationship between the size of an administered dose and the intensity of the response produced.

Answer 2

dose-response relationship

Question 3

Is the dose-response relationship graded or all-or-nothing? what is the importance of this?

Answer 3

Graded, which gives us more control and allows us to fit the needs of the patient. If it were all-or-nothing, and could only produce one intensity of response, we could not treat various patients with that drug.

Question 4

_____ _____ is defined as the largest effect that a drug can produce. It is indicated by the height of the dose-response curve.

Answer 4

Maximum Efficacy

Question 5

T or F: A drug with very high maximal efficacy is more desirable than a drug with lower efficacy.

Answer 5

False, we want to match the intensity of the response to the patient’s needs. Ex. Furosemide can cause dehydration because it is a high efficacy diuretic. We may choose a lower efficacy to reduce the intensity of volume of water to be mobilized.

Question 6

The term ______ refers to the amount of drug we must give to elicit an effect.

Answer 6

potency

Question 7

If morphine produces pain relief at a lower dose than meperidine, is it more potent or less potent?

Answer 7

more potent

Question 8

Drugs are chemicals that interact with chemicals inside the body. ________ are the special chemicals in the body to produce effects. It is any functional macromolecule in a cell to which a drug binds to to produce effects.

Answer 8

Receptors

Question 9

The binding of drugs to receptors can either _____ or ____ the action of the body’s own regulatory molecules.

Answer 9

mimic (agonist) or block (antagonist)

Question 10

T or F: Drugs produce their therapeutic effects by helping the body use its pre-existing capabilities. Drugs cannot give cells new functions.

Answer 10

True

Question 11

There are four primary receptor families.

1. Cell membrane embedded ______
2. __ protein-coupled systems
3. ligand-gated ____ channels
4. transcription factors

Answer 11

1. enzymes
2. G
3. ion

Question 12

Transcription factors differ from other receptors in two ways. 1. They are found _____ the cell rather than _____ the cell. 2. Responses to activation of these receptors are _____ instead of _____.

Answer 12

p.52

1. inside/within the cell rather than outside the membrane
2. delayed versus instant, or within milliseconds.

Question 13

Transcription factors are situated in the nucleus on the DNA; therefore, they can only be activated by ______ that are ______ soluble.

Answer 13

ligands; lipid

Question 14

The more selective a drug is, the fewer side effects it will produce. Why is that?

Answer 14

Selective drug action is possible because drugs act through specific receptors. p.52

Question 15

If drugs are selective for one receptor only, why does the drug still cause some side effects?

Answer 15

The receptor may be located in more than one area of the body, causing side effects.

Question 16

_______ _______ Theory states that the intensity of response to a drug is proportional to the number of receptors occupied.

Answer 16

Simple Occupancy Theory

Question 17

The strength of the attraction between a drug and its receptor.

Answer 17

Affinity

Question 18

T or F: Drugs with high affinity (attraction to receptors) can bind when present in low concentrations. This means drugs with high affinity are potent.

Answer 18

True.

Question 19

This term refers to the ability of a drug to activate a receptor upon binding. The higher this activity, the more intensely a receptor is activated.

Answer 19

intrinsic activity

Question 20

Affinity is to potency as Intrinsic activity is to ______ _____.

Drugs with high intrinsic activity cause intense receptor activation, therefore intense responses.

Answer 20

maximal efficacy

Question 21

T or F: Agonists are molecules that activate receptors. These molecules include neurotransmitters, hormones, other endogenous regulators as well as drugs that mimic them.

Answer 21

True

Question 22

__________ produce their effects by preventing receptor activation by endogenous regulatory molecules and drugs.

Answer 22

antagonists

Question 23

Affinity allows the agonist to bind to receptors. What does intrinsic activity allow?

Answer 23

Allows the bound agonist to activate or turn on the receptor function. p.54

Question 24

T or F: If there is no agonist present, antagonist will still have an effect.

Answer 24

False. antagonist prevents agonist from activating receptor. If there is no activation, antagonist cannot deactivate.

Question 25

Antagonist can be competitive or non-competitive. Non-competitive bind ________ to receptors. They reduce the maximal response an agonist can elicit.

Answer 25

irreversibly.

Because irreversible they are rarely used therapeutically.

Question 26

Because competitive antagonists bind reversibly to receptors, the inhibition they cause is _________.

Answer 26

surmountable.

Question 27

What causes down-regulation? Hint: Down-regulation is also referred to as desensitized or refractory.

Answer 27

When receptors of a cell are continually exposed to an agonist, the cell usually becomes less responsive.

Question 28

What is interpatient variation?

Answer 28

The variation in response to a drug from patient to patient.

Question 29

What is ED50?

Answer 29

The average effective dose.

Question 30

What can a nurse do to address interpatient variability?

Answer 30

After initial dose, monitor and then fine tune. If there is not a great response after an ED50, discuss increasing the dose with a dr. In the case of pain meds, you must address the patient’s concern. Be cautious of the lethal dose!!!