Pharmacodynamics and drug-receptor interaction

Question 1

pharmacodynamics

Answer 1

study of biochemical, cellular, and physiological effects of drugs and their mechanics of action

Question 2

Chemical mechanism of drug action

Answer 2

chemical nature of the drug alters the physiologic environment of the target tissue to produce an effect

Question 3

Antacids

Answer 3

increase pH of gastric lumen to neutralize gastric acid thereby decreasing irritation to the lining of the stomach

Question 4

Osmotic diuretics

Answer 4

increase osmolarity of tubular fluid in kidney to decrease the reabsorption of water which increases urine output

Question 5

chelating agents

Answer 5

drugs that chemically bind to target molecules

Question 6

digibind

Answer 6

used as an antidote for digoxin toxicity

Question 7

deferoxamine

Answer 7

used as an antidote for iron toxicity

Question 8

Receptor binding

Answer 8

drug functions as ligands that bind to receptors that regulate cellular processes

Question 9

Agonist

Answer 9

when it binds to the receptor, results in producing a desired response of the receptor

Question 10

Antagonist

Answer 10

when it binds to the receptor, it stops producing a desired response of the receptor

Question 11

Receptor types

Answer 11

ligand gated ion channels
GPCR
enzyme linked receptors
intracellular receptors

Question 12

What is Kd

Answer 12

equilibrium dissociation constant
ratio of the dissociation rate to the association rate

Question 13

Affinity

Answer 13

strength of interaction between a ligand and its receptor

Question 14

Kd= ?

Answer 14

([L][R])/ [LR]

Question 15

The formation of the ligand/drug-receptor complex is determined by?

Answer 15

affinity

Question 16

Affinity constant

Answer 16

Ka
reciprocal of the equilibrium dissociation constant

Question 17

Drugs with a high affinity have what kind of Kd?

Answer 17

low

Question 18

Fraction occupancy of receptors= ?

Answer 18

[LR]/([R]+[LR])

describes the magnitude of biological effect related to the amount of active receptors— agonists can infect this

Question 19

When the concentration of free drug increases the concentrations of bound receptors to total receptors plateaus. This is known as?

Answer 19

the maximal effect

Question 20

potency

Answer 20

amount of drug needed to produce an effect

Question 21

EC50

Answer 21

concentration of the drug that produces 50% of the maximum effect; determines potency

Question 22

Efficacy

Answer 22

ability of ligand to produce a pharmacological response

Question 23

Emax

Answer 23

maximal effect of a drug

Question 24

factors that affect biological response

Answer 24

[agonist]
affinity of agonist for the receptor
fraction of occupied receptors

Question 25

intrinsic activity

Answer 25

ability of a drug to fully/partially activate the receptors

Question 26

Full agonists

Answer 26

intrinsic activity ~ 1 can produce a maximal response

Question 27

Partial Agonists

Answer 27

0 < intrinsic activity < 1 produces less than a maximal response

Question 28

Inverse agonists

Answer 28

intrinsic activity < 0 reverse the activation state of receptors exert opposite pharmacological effect of agonists

Question 29

Competitive antagonists

Answer 29

bind reversible to the receptor on the same site interferes with binding to its receptor maintain the receptor in the active states reduces antagonist potency, incr EC50

Question 30

Non competitive antagonists

Answer 30

bind irreversibly and covalently to the receptor on the same site reduces the number of receptors available to the agonist permanently decr Emax no shift of EC50 values

Question 31

As concentration of antagonist increase in competitive antagonism, response curves shift to the?

Answer 31

right

Question 32

Which way do response curves shift in non competing antagonism?

Answer 32

right and down

Question 33

Allosteric antagonists

Answer 33

bind to allosteric site decr Emax no shift of EC50 value decrease affinity of receptor for the against can potential effects of primary agonists

Question 34

ED50

Answer 34

median effective dose dose required to produce a desired effect in 50% of the population

Question 35

ED99

Answer 35

dose of a drug that produces a desired effect in 99% of the population

Question 36

LD50

Answer 36

median lethal dose dose producing toxicity in 50% of the population

Question 37

LD1

Answer 37

dose producing toxicity in 1% of the population

Question 38

Therapeutic index

Answer 38

ratio that compares [blood] at which a drug becomes toxic and the concentration at which the drug is effective LD50/ED50 measure of a safety of a drug

Question 39

large therapeutic index indicates

Answer 39

a wide margin between effective dose and lethal dose

Question 40

therapeutic window

Answer 40

range of steady-state concentrations of drug providing therapeutic efficacy with minimal toxicity

Question 41

In most drugs, what kind of therapeutic index values are required?

Answer 41

high

Question 42

factors affecting the response to a prescribed drug dose

Answer 42

medication errors patient compliance

Question 43

factors affecting administered dose

Answer 43

rate and extent of absorption body size and composition distribution in body fluids binding in plasma and tissues rate of metabolism and excretion

Question 44

factors affecting concentration at site of action

Answer 44

physiological variables pathological factors genetic factors interaction with other drugs development of tolerance and desensitization

Question 45

factors affecting drug effects

Answer 45

drug receptor interaction functional state of targeted system selectivity of drug propensity to produce unwanted effects placebo effects resistance