chapter 4 Pharmacodynamics

Question 1

What is the median effective dose

Answer 1

-the dose in the middle of the frequency distribution curve
-the dose that is required to produce a therapeutic effect in 50% of patients in a group
-Usually the ED50 is average or standard dose of a drug

Question 1

What is pharmacodynamics

Answer 1

what the mechanisms of drug action are and how drug drug concentration affects the body’s response

Question 2

what are the three main pharmacodynamic factors that affect interpatient variability

Answer 2

Dose response relationships
Therapeutic index
drug receptor interactions

Question 3

what is therapeutic Index***

Answer 3

ratio of drugs LD50 to its ED50 measure of a drugs safety margin the higher the value the safer the medication

Question 4

how would you calculate therapeutic index

Answer 4

(median lethal dose)/(median Effective dose)

Question 5

what is margin of safety

Answer 5

another indicator of a drugs effectiveness and safety

Question 6

How is margin of safety calculated

Answer 6

(amount of drug that is lethal to 1% of animals)/(amount of drug that produces a therapeutic effect in 99% of animals)

Question 7

What is dose response relationship

Answer 7

describes how the action of drug changes with increasing dose

Question 8

what are the three phases of the dose response curve

Answer 8

1: lowest dose
2: Most desirable range
3: plateau reached

Question 9

if you were to increase a dose past phase 3 of the dose response curve what could happen

Answer 9

if you were to keep increasing the dose it will only increase the toxic effects and not the therapeutic effects

Question 10

WHat medication do you need to be very aware of the dose response relationship***

Answer 10

antibiotics

Question 10

what is potency of a drug***

Answer 10

Amount of drug needed to produce a specific effect

Question 11

what is efficacy of a drug***

Answer 11

Greatest maximal response produced by a drug

Question 12

which one is more important efficacy or potency in determining if a drug is more therapeutic**

Answer 12

efficacy

Question 13

What is receptor theory

Answer 13

states that majority of drugs produce therapeutic effects by inhibiting or stimulating receptor sites

Question 14

if a drug had a high intrinsic activity what would that mean

Answer 14

this would mean that the drug has the ability to bind to a receptor and produce a strong action

Question 15

do most drugs work by creating anew action within the body or enhancing or inhibiting a physiological response**

Answer 15

most drugs enhance or inhibit a physiologic process

Question 16

What is an agonist drug

Answer 16

a drug that activates a receptor and produces the same type of response as the endogenous substance

Question 17

can an agonist drug produce a greater response than normal endogenous activity

Answer 17

yes

Question 18

what is an antagonist drug

Answer 18

a drug that prevents the action of endogenous substances and has no intrinsic activity itself it only produces an effect by blocking receptors

Question 19

would you use an agonist or antagonist drug to reverse an OD

Answer 19

antagonist since it would block receptors and stop the OD from happening

Question 20

how does functional antagonism produce an effect

Answer 20

it has an effect not by competing for receptors but by changing pharmacokinetic factors for example if a functional antagonist speed up metabolism it would reduce the absorption of an agonist

Question 21

what is a partial agonist medication

Answer 21

medication that produces a weaker response than an agonist

Question 22

do partial agonists have a ceiling effect

Answer 22

yes

Question 23

what is a synergistic paring of drugs

Answer 23

when two drugs are given together so they have an enhanced effect (1+1=3)

Question 24

what is a potentiate pairing of drugs

Answer 24

a drug that has no effect is given to enhance the effect of a drug that does have an effect (1+0=2)

Question 25

What is an additive pairing of drugs

Answer 25

when two drugs with similar pharmacological actions are given together to produced a greatly enhanced effect (1+1=3)

Question 26

What is a very common additive pairing of drugs

Answer 26

Diuretic and beta blocker to lower BP

Question 27

what is a controlled substance***

Answer 27

a substance that has the potential for abuse or addiction that is regulated by the government

Question 28

what is a scheduled drug***

Answer 28

a scaling system of a drugs abuse or dependancy potential

Question 29

What factor is a reflection on a drug’s ability to bind to a receptor potency or efficacy

Answer 29

potency

Question 30

What is a potential outcome of a prescription drug that has a high margin of safety***

Answer 30

may be reclassified as over the counter

Question 31

once phase 3 of the dose response curve is reached what would happen if you increase the dose of antibiotics***

Answer 31

could result in toxicity

Question 32

Can drugs in the same class differ in potency and efficacy? ***

Answer 32

Yes

Question 33

What does therapeutic effect mean ***

Answer 33

Desired outcome

Question 34

What does bioavailability mean ***

Answer 34

the amount of free drug in the blood stream available to interact with cells

Question 35

What does safety margin mean***

Answer 35

the amount between a therapeutic dose and a lethal dose of drug

Question 36

What is a therapeutic dose ***

Answer 36

the quantity of drug required to obtain the desired effect with a safe outcome