pharmacodynamics

Question 1

definition of pharmacodynamics

Answer 1

is the study of the mechanism of action of a specific drug

it is the relationship between drug concentration and responses that occur in the body due to the drug

Question 2

why be concerned about how drug work?

Answer 2

knowledge of how a drug works increases the nurse’s confidence and it ensures that the drug is being used appropriately to prevent medication error.

improves the ability to educate, assess and evaluate patients

Question 3

definition of mechanism of action

Answer 3

means the way a drug produces a therapeutic effect. once the drug hits its site of action it can modify the way a cell of tissue functions . mechanism of action of most drugs involve the interaction of the drugs with receptors or enzymes.

Question 4

what is a drug-receptor

Answer 4

it is a specialised macromolecule to which a specific group of drugs or naturally occuring substances can bind

Question 5

once the substance binds to and interacts with the receptor, a __________ is produced

Answer 5

pharmacologic response / therapeutic effect

Question 6

what is the receptor theory?

Answer 6

it is when a drug molecule binds to a reactive site on the cell which is the receptor. once the substance binds to and interacts with the receptor a pharmacologic response/therapeutic effect is produced

Question 7

_____+__________= drug affect

Answer 7

drug and receptor

Question 8

what are the structures of receptors

Answer 8

most receptors are proteins found on the plasma membrane of a cell or tissue

some receptors are intracellular molecules such as DNA or enzymes in the cytoplasm

Question 9

what is the function of receptors?

Answer 9

is to bind endogenous molecules

Question 10

what are some examples of endogenous molecules?

Answer 10

hormones and neurotransmitters

Question 11

when a drug binds to a receptor is can be classified as either :

Answer 11

agonist or antagonist

Question 12

what is agonist?

Answer 12

agonist mimics the effect of the endogenous substance that normally binds to the receptor and produces the response

Question 13

examples of agonist

Answer 13

epinephrine (adrenaline) neurotransmitter

the epinephrine neurotransmitter, at the adrenergic synapses, is an agonist. it is produced by the adrenals, it binds to the receptor and there is a response for our fight and flight

Question 14

what is the antagonist?

Answer 14

drug occupies the receptor and prevents the endogenous substance from binding.

The drug binds to receptor prevents binding of agonist.

Question 15

example of antagonist

Answer 15

alpha and beta adrenergic blockers

Question 16

blockage of myocardial beta 1 receptors may

Answer 16

decrease force and rate of. contraction

Question 17

what is affinity

Answer 17

affinity is the degree to which a drug binds with a receptor

Question 18

the drug with the best ________ or _______ will elicit the best response

Answer 18

best fit or affinity

Question 19

what are enzymes

Answer 19

enzymes are substances that catalyze nearly every biochemical reaction in a cell

Question 20

drugs can interact with enzyme systems to

Answer 20

alter a response

Question 21

Enzyme inhibitors _______ action of enzymes

Answer 21

inhibits

Question 22

what is the function of enzyme inhibitors

Answer 22

it inhibits action of enzymes. the enzyme is fooled into binding to a drug instead of a target cell. it protects target cell from enzyme’s action.

Question 23

what do ACE ( angiotensin-converting enzyme inhibitors) inhibitors do?

Answer 23

it reduced blood pressure

Question 24

how does an enzyme system work?

Answer 24

1) substrate enters the active site of the enzyme
2) enzyme-substrate complex forms
3) substrate is converted to products
4) products leave the active site of the enzyme

Question 25

what are non-specific interactions?

Answer 25

some drugs bypass the enzyme system. MOA of some drugs is that they do not go to a receptor site or alter an enzyme function. main site of action is cell membrane or cellular process. these drugs will physically interfere or chemically alter cell process. final product is altered causing defect or cell death.

Question 26

where is the main site of action of non-specific interaction drugs?

Answer 26

cell membrane

Question 27

examples of non-specific interaction drugs

Answer 27

cancer drugs, antibiotics

Question 28

what is a therapeutic index

Answer 28

it is the measure of the safety of a drug it is the ratio between a drug's therapeutic benefits and its toxic effects.

Question 29

therapeutic index formula

Answer 29

median lethal dose LD50/ median effective dose ED50

Question 30

what is a median lethal dose (LD50)

Answer 30

the amount of drug that will be lethal in 50% of a group of animals

Question 31

what is a median effective dose (ED50)?

Answer 31

the amount of a drug required to produce a response in 50% of the subjects to whom the drug is given

Question 32

low therapeutic index =

Answer 32

not good because it means the safety margin is small

Question 33

what is the relationship between the therapeutic index and safety of a drug

Answer 33

the higher the TI, the safer the medication

Question 34

larger the TI, the _____ the drug

Answer 34

safer

Question 35

must be > ___ for the drug to be usable

Answer 35

1

Question 36

when a drug is given to a single patient, the intensity of the response can be seen in a ____________

Answer 36

drug-response curve

Question 37

how many phases in drug-response curve?

Answer 37

3

Question 38

what happens during phase 1

Answer 38

occurs at lowest dose . few target cells affected by drug

Question 39

what happens during phase 2

Answer 39

linear relationship. linear relationship between amount of drug administered and degree of client response. i.e doubling the dose doubles the drug response

Question 40

which phase is the most desirable

Answer 40

phase 2

Question 41

what happens during phase 3

Answer 41

increasing dose has no therapeutic effect the increased dose may produce adverse effects

Question 42

what is potency

Answer 42

refers to the measure of how much a drug is required in order to produce a particular effect.

Question 43

what is efficacy

Answer 43

refers to the magnitude of the maximal response that can be produced by the drugs

Question 44

drug interaction may occur with either

Answer 44

with either drugs or food

Question 45

what are drug-drug interactions

Answer 45

changes in a drug's effect caused by the presence of another drug taken during the same period

Question 46

type of drugs which are at risk of drug interaction

Answer 46

- narrow TI (low safety drug) - steep dose-response curves - drugs where a loss of effect may lead to disease breakthrough

Question 47

why do drugs with steep dose-response curves at risk of drug interaction

Answer 47

a minor change in plasma concentration may take a major change in effect example warfarin

Question 48

patients who are at risk of drug interaction

Answer 48

- elderly, polypharmcy, poor homeostatic mechanism - severely ill patients - patients who depend on prophylactic therapy for disease suppression

Question 49

those who are at risk of drug interaction

Answer 49

patient with renal of liver disease patient with more than one physician

Question 50

types of drug-drug interactions

Answer 50

duplication opposition (antagonism) alteration

Question 51

describe and explain what happens during duplication

Answer 51

duplication may occur when a person inadvertently takes two drugs, that have the same active ingredient. when two drugs with the same effect are taken, their therapeutic effects and their side effects may be intensified.

Question 52

what is opposition

Answer 52

when two drugs with opposing actions interact, reducing the effectiveness of one or both

Question 53

what is alterations

Answer 53

one drug may alter how the body absorb, distributes, metabolizes, or excretes another drug

Question 54

what are drug-food interactions

Answer 54

changes in a drug's effects caused by food consumed in the same period of time

Question 55

presence of food in the digestive tract may _____________ of a drug

Answer 55

reduce absorption

Question 56

what happens when warfarin interact with foods rich in vitamin k such as broccoli, spinach

Answer 56

reduce the effectiveness of anticoagulants (warfarin) increasing the risk of clotting. intake of such foods should be limited and the amount consumed daily should remain constant

Question 57

what happens when tetracycline interact with calcium foods

Answer 57

these foods can reduce the absorption of tetracycline, which should be taken 1 hour before or 2 hours after eating

Question 58

what happens when statins interact with grapefruit

Answer 58

grapefruit contains substance that affects the intestinal absorption of drugs such as statins

Question 59

what is drug-medicinal herb interactions

Answer 59

drugs interact with certain medicinal herb or supplement taken by patients at the same time

Question 60

what is an adverse drug reaction

Answer 60

is an adverse outcome of drug therapy in which a patient is harmed in some way

Question 61

causes of ADR

Answer 61

pharmacologic reactions hypersensitivity reactions idiosyncratic reactions

Question 62

Pharmacologic reactions are ________, ______ -related, , occurs due to _________

Answer 62

predictable, dose, action of drug

Question 63

hypersensitivity reactions are _______-related , requires _____________, _______ develop when drug acts as antigen or allergen , ______________ produces hypersensitiy reaction

Answer 63

not dose, prior exposure, allergies, subsequent exposure

Question 64

idiosyncratic reactions are ___________, ______-realted or allergic, occurs in __________ percentage of people

Answer 64

unexpected, not dose-related, small

Question 65

ADRS is also known as

Answer 65

side effects

Question 66

if a drug is teratogenic

Answer 66

it causes fetal malformation

Question 67

if a drug is mutagenic

Answer 67

it causes mutations of DNA

Question 68

if a drug is carcinogenic

Answer 68

it causes cancer

Question 69

if a drug causes tolerance

Answer 69

there is a decreasing response when repeated doses are given

Question 70

if a drug causes dependence

Answer 70

patients have a physiologic or psychological need to a drug