Intro to Pharmacodynamics

Question 1

Receptor:

what role does it play?

initiates what events?

Answer 1

regulatory role

interacts with a drug and initiates the biochemical events leading to drug effect

Question 2

Drug-Receptor Interaction–> Covalent

• can it be reversed?
• reactivation requires?

Answer 2

Irreversible and reactivation requires resynthesis of the receptor or enzymatic removal of the drug

Question 3

Drug Receptor Interaction–> Noncovalent

• is it reversible?
• how common

Answer 3

reversible, most drugs bind to receptors via non-covalent bonds

Question 4

Strongest to weakest drug receptor interactions

(four)

Answer 4

Ionic>hydrogen>hydrophobic>Van der waals

Question 5

Hyperbolic curve

x axis?

y axis?

Answer 5

drug dose on the x axis

drug effect on the y axis

Question 6

how do you get a sigmoidal dose response curve?

-x, vs y axis

Answer 6

log of drug dose on x

response on y

more common than hyperbolic curve

Question 7

E_max

-define

Answer 7

The maximal effect that can be produced by the drug

Question 8

ED₅₀

Answer 8

The dose of the drug that produces 50% of its maximal effect

Question 9

Graded Response curve:

• what question does it answer?
• What varies continuously?
• represents mean value of what?

Answer 9

Answers the question how much

magnitude of a response varies continously

typically represents the mean value within a population or a single subject

Question 10

Quantal Response:

• question it answers
• type of response
• requires what
• used for what?

Answer 10

all or none; yes-no binary response

• does the response occur or not?
• in how many?
• requires a pre-defined response (death, falling asleep, 10% reduction in bp)
• used to examine the frequency of the number of individuals showing a response within a large population

Question 11

non-cumulative quantal dose-response curve

-define

Answer 11

number or percent of individuals responding at a certain dose of a drug and only at that dose

Question 12

Cumulative quantal dose response curve

-define

Answer 12

number or percent of individuals responding at a certain dose of a drug AND at all doses lower than that dose

Question 13

Therapeutic index:

• what ratio?
• meaning of the value?

Answer 13

TD₅₀/ED₅₀

higher the TI the safer the drug

Question 14

Therapeutic window:

-define

Answer 14

range of doses of a drug or of its concentration in a bodily system that provides for the safe and effective therapy

Question 15

K_D:

• meaning of this value
• unit
• low vs high

Answer 15

K_D is the equilibirum dissociation constant, which is the drug concentration at which 50% of the drug receptor binding sites are occupied by the drug

• unit is molar concentration
• lower the value, higher the affinity of a drug for a receptor

Where [L], [R] and [LR] represent molar concentrations of ligand, receptor, and their complex

Question 16

What is the EC₅₀

-how is it different than K_D

Answer 16

• It is simply the concentration of agonist required to provoke a response halfway between the baseline and maximum responses. Because the EC50 defines the location of the dose-response curve for a particular drug, it is the most commonly used measure of an agonist’s potency.
• However, the EC50 is usually not the same as the Kd for the binding of agonist to its receptor – it is not a direct measure of drug affinity.

Question 17

-Magnitude of a drug’s effects will be proportional to what?

Answer 17

proportional to the degreee of its interaction with a receptor

Question 18

Drug selectivity:

• define
• measured how?

Answer 18

• property of a drug determined by its affinities at various binding sites
• measured by comparing affinities of a drug to different receprots
• a more selective drug would affect fewer targets over a specific concentration range (therapeutic range)

Question 19

Intrinsic activity:

-define

Answer 19

ability of a drug to change a receprot function and produce a physiological response upon its binding to a receptor

Question 20

Agonist

-definition, does it have intrinsiv activity?

Answer 20

bind to the receptor and stabilize it in a particular conformation (usually active), producing a physicological response

*have an intrinsic activity*

Question 21

Antagonist

• define, does it have intrinsic activity?
• effect in absence of an agonist?

Answer 21

• receptor antagonists bind to the receprot but do not change its function. however, they prevent activation of the receport in the presence of an agonist
• don’t have intrinsic activity
• don’t change function of receptor upon binding
• no pharmacological effect in the absence of an agonist

Question 22

Full agonist:

• when do they produce maximal pharm. effect?
• intrinsic activity levels?

Answer 22

fully activate receptors producing a max pharm effect when all receptors are occupied

-maximal intrinsic activity

Question 23

partial agonist:

• describe activation of receptor
• pharm effect
• intrinsic efficacy

Answer 23

partially activate the receptor upon binding

• produce a sub-maximal pharm effect when all receptors are occupied
• intrinsic efficacy varies depending on drug, but ALWAYS submaximal

Question 24

Inverse Agonists:

• effect on receptor signaling
• constitutive receptor activity?
• intrinsic activity, why?

Answer 24

• decrease receptor signaling
• decrease response at receprotrs with a significant level of constitutive receptor activity
• intrinsic activity is present and related to the inhibition of receptor function

Question 25

Pharmacologic antagonism Chemical antagonism Physiologic antagonism

Answer 25

Pharm: (receptor) antagonism action at the same receptor as endogenous ligands or agonist drugs Chemical: when chemical antagonist makes the other drug not available Physiologic: occurs between endogenous pathways regulated by different receptors

Question 26

Competitive antagonist: - compete with what? - can be displaced by what

Answer 26

- compete with endogenous chemicals or agonist drugs for binding to the receptor - can be displaced from the receptor by other drugs (effects are surmountable)

Question 27

Non-competitive antagonists: types, define (x2)

Answer 27

-receptor inactivation is not surmountable Irreversible antagonists: irreversibly bind to and occlude the agonist site on the receptor by forming covalent bonds Allosteric antagonists: bind to a site other than the agonist site to prevent or reduce agonist binding or activation of the receptor

Question 28

Competitive antagonism: - EC₅₀ effect - E_max effect

Answer 28

-EC₅₀ increases, E_max does not change

Question 29

Noncompetitive antagonism: - effect on EC₅₀ - effect on E_max

Answer 29

EC₅₀ does not change, but E_max decreases

Question 30

Drug Potency: - define - what drugs tend to be more potent - what value represents drug potency? (lower vs higher)

Answer 30

- Potency describes the amount of drug required to produce a specific pharmacological effect - drugs with higher affinities for a receptor--\> lower K_D tend to be more potent - potency describes the amount of drug required to produce a specific effect and is represented by the ED₅₀--\> the lower the value, the more potent \*determines the drug dose that will be used clinically\*

Question 31

Drug Efficacy: - define - represented by what value? - efficacy is related to total number of? - determines clinical what?

Answer 31

- describes the maximal pharmacological effect the drug can produce - represented by the E_max, the greater the E_max the more efficacious the drug - efficacy is related to the total number of receptors available to bind a drug, and it determines the clinical effectiveness of a drug

Question 32

Describe increasing potency vs increasing efficacy graphs

Answer 32

Question 33

microgram -define

Answer 33

1/1000th of a milligram, which is 1/1000th of a gram

Question 34

1 kg = how many pounds?

Answer 34

2.2

Question 35

Volume: -tsp, tbsp, ounce, cup

Answer 35

Question 36

Volume: - ml/cc - quart=how many ml? how many pints in quart? - pint=ml? how many oz in one pint? - gallon=how many L? quarts in a gallon? pints in gallon?

Answer 36

Question 37

Dosing Frequency abbreviations: - qd - bid - tid - qid - qod - q"x"h

Answer 37

Question 38

Dosing frequency: - qam - qpm - qhs - prn - ac - pc

Answer 38

Question 39

Routes of administration: - od - os - ou - ad - as - au - gtt

Answer 39

Question 40

Routes of administration: - po - sl - iv - im - sq - pr - NGT - OGT

Answer 40

Question 41

abbreviations: - ut.dict. - tra - kvo

Answer 41

- as directed - to run at - keep vein open

Question 42

of gms in 100ml

Answer 42

W/V%