G.D , Q.D & CLINICAL DOSE RESPONSE

Question 1

T or F: The intensity of drug effect (response) on animal is generally proportional to
the dose of the drug.

Answer 1

TRUE

Question 2

Factors which affect the amount of drug that finally gets to the receptor
sites

Answer 2

1. Physicochemical properties of the drug including rate of dissolution and
   lipid solubility
2. Blood flow through the site of absorption (less blood flow, less drug
   absorbed).

Question 3

the elicited response could be measured in continuous scale.

Answer 3

GRADED DOSE RESPONSE

Question 4

also termed quantal response, an individual unit of a
biological system responds to a drug dose either maximally or not at all.

Answer 4

ALL or NONE RESPONSE

Question 5

the smallest dose at which death occurs.

Answer 5

Threshold dose or minimal lethal of effective dose

Question 6

– the differences in the susceptibility to chemicals among
individuals.

Answer 6

Biologic variation

Question 7

Two important Factors to consider during the drug test

Answer 7

1. EFFECTIVE DOSE
2. LETHAL or TOXIC DOSE

Question 8

may also be used to refer to any unwanted effects other then death.

Answer 8

LETHAL DOSE

Question 9

can be constructed for responses that are measured on a
continuous scale, eg, heart rate. It also relate the
intensity of response to the size of the dose, and hence are useful for characterizing the actions of drugs.

Answer 9

Graded dose- response-curve

Question 10

can be constructed for drugs that elicit an all-or-non response, eg, presence or absence of epileptic seizures.

Answer 10

Quantal dose-responsive-curve

Question 11

When these data are plotted as a cumulative frequency distribution, a _______________________ is generated.

Answer 11

sigmoidal dose-response curve

Question 12

This is a measure of how tightly a drug binds to its receptor.

Answer 12

Equilibrium Dissociation Constant (K D)

Question 13

two rate constants

Answer 13

1. (forward reaction, k1)
2. (reverse reaction, k2)

Question 14

reaction between the drug and receptor and the drug-receptor complex.

Answer 14

Forward reaction, K1

Question 15

is the ratio of rate constants for the reverse

Answer 15

Reverse reaction, k2

Question 16

drug with _______dissiociate rapidly from receptors;

Answer 16

high KD (low affinity)

Question 17

Examples of specific drugs

Answer 17

1. atropine (a muscarinic antagonist)
2. salbutamol (a β 2 -adrenoceptor agonist)
3. phenoxybenzamine (an a-alergic blocking agent) 4.cimetidine drug effects

Question 18

a muscarinic antagonist

Answer 18

ATROPINE

Question 19

a β 2 -adrenoceptor agonist

Answer 19

SALBUTAMOL

Question 20

an a-alergic blocking agent

Answer 20

PHENOXYBENZAMINE

Question 21

causes blockade of D 2 -dopamine receptors, a-adrenergic receptors, and muscarinic receptors.

Answer 21

PHENOTHIAZINE

Question 22

is the ration of the dose that results in an
undesired effect to that which results in a desired effect.

Answer 22

Therapeutic index

Question 23

The therapeutic index of a drug is usually defined as the ratio of__________which indicates how
selective the drug is in resulting in its desired effect.

Answer 23

LD50 to ED50,

Question 24

LD5O & ED ED50 are derived from ?

Answer 24

quantal dose-response curves

Question 25

The maximal efficacy of the drug-receptor complex to result in a graded effect is _____ on a graded dose-response curve.

Answer 25

Emax

Question 26

plotting plasma concentrations of a drug (abscissa) versus therapeutic effect (ordinate) in chronologic order displays the data as a loop. This phenomenon is referred to as

Answer 26

hysteresis

Question 27

A counterclockwise hysteresis loop is observed of a drug such as?

Answer 27

Digoxin

Question 28

The extent and duration of action of a competitive antagonist depends on its concentration in the?

Answer 28

Plasma

Question 29

may occur as a result of continual stimulation by an agonist, and manifests as the development of tachyphylaxis, which demonstrates a clockwise hysteresis loop in the concentration-effect relationship,

Answer 29

Down-reuglation of receptors

Question 30

The ____ of drug for a receptor describe ***how avidly the drug binds to the receptor*** (ie, the K D ).

Answer 30

AFFINITY

Question 31

refers to the concentration (EC 50 ) or dose (ED 50 ) of a drug required to produce 50% of the drug’s maximal effect.

Answer 31

POTENCY

Question 32

Potency depends on both the?

Answer 32

affinity & efficacy

Question 33

(also referred to as intrinsic activity) of a drug is the ***ability of the drug to elicit a response when it binds to the receptor.***

Answer 33

EFFICACY

Question 34

is the concentration of an antagonist that ***reduces a specified response to 50%*** of the maximal possible effect.

Answer 34

median inhibitory concentration or IC 50

Question 35

refers to a drug’s ability to ***preferentially produce a particular effect*** and is related to the structural specificity of drug binding to receptors.

Answer 35

SELECTIVITY

Question 36

binds equally well to ***1 -adrenoceptors***;

Answer 36

propranol (a β-blocker)

Question 37

β-agonist used for ***treating asthma binds*** selectively to β 2 -adrenoceptors.

Answer 37

SALBUTAMOL

Question 38

selectivity of salbutamol may be further enhanced by administering it directly to the?

Answer 38

LUNGS

Question 39

drugs with a ________dissociate slowly from receptors.

Answer 39

low K D (high affinity)

Question 40

obtained from either graded or quantal dose-response curves is used to determine the dose that should be administered.

Answer 40

drug’s potency

Question 41

provides information concerning the dose range over which a ***drug elicits its effect.***

Answer 41

The slope of the graded dose-response curve

Question 42

indication of the ***ability of drugs to reach the receptor*** is obtained from _______ _______that characterize the absorption, distribution, and clearance of a drug.

Answer 42

pharmacokinetics parameters