Lab 8

Question 1

drug-receptor interactions occur via which bonds

Answer 1

ionic
hydrogen
van der Waals
covalent

Question 2

drugs with a ____ duration of action generally have WEAKER bonds

Answer 2

short

Question 3

what kind of drug-receptor interactions may have stronger bonds?

Answer 3

long duration or irreversible interactions (such as covalent)

Question 4

define drug receptors

Answer 4

generally proteins that bind endogenous molecules to elicit physiological effects

Question 5

define an agonist

Answer 5

a chemical that activates a receptor to produce a biological response

Question 6

define a full agonist

Answer 6

activates a receptor with the maximum response that an agonist can elicit at the receptor

Question 7

define a partial agonist

Answer 7

binds and activates a given receptor, but only has PARTIAL EFFICACY at the receptor (relative to a full agonist)

EVEN AT MAXIMAL RECEPTOR OCCUPANCY

Question 8

define an inverse agonist

Answer 8

binds to a receptor and produces the opposite of its normal response (agonist response)

Question 9

define an antagonist

Answer 9

blocks or dampens a biological response by binding to and blocking a receptor

Question 10

pharmacodynamics relates to what properties of the drug?

pharmacokinetics relates to what properties of a drug?

Answer 10

pharmacodynamics relates to drug EFFECT and CONCENTRATION

pharmacokinetics is related to concentration and time

Question 11

TOGETHER, pharmaodynamics and pharmacokinetics provides…..

Answer 11

the relationship of a drug’s effects over time

called the TIME COURSE OF EFFECT

Question 12

“Time course of drug action” is a function of…..

Answer 12

drug absorption, distribution, metabolism, excretion (pharmacokinetics)

Question 13

the INTENSITY of a response elicited by a drug is a function of…

Answer 13

the dose administered and the concentration of the drug at the site where the action-effect sequence is initiated

Question 14

the proportion of the dose that actually contributes to the concentration at the site of action is the NET RESULT OF THE RATE AND EXTENT OF—–

Answer 14

absorption - distribution - metabolism - excretion

Question 15

define absorption

Answer 15

the rate at which a drug leaves its site of administration and becomes BIOAVAILABLE

Question 16

name 5 factors that affect transport across membranes and influence absorption

Answer 16

-solubility
-concentration
-circulation to the site of -absorption
-surface area of absorption
-route of administration

Question 17

binding to plasma proteins will _____ the rate of passive absorption.
how?

Answer 17

increase

by maintaining the concentration gradient of free drugs

Question 18

after a drug is absorbed or injected into the bloodstream, what may happen

Answer 18

may be distributed into interstitial and cellular fluids

Question 19

what organs receive most of the drug during the first few minutes after absorption?

Answer 19

heart
liver
kidney
brain
other well-perfused organs

Question 20

deliver (distribution) to what parts of the body is slower?

Answer 20

to muscle and most other viscera
skin
fat

may require several minutes to several hours before a steady state is attained

Question 21

binding to plasma proteins will _____ the distribution of drugs to other tissues

Answer 21

decrease

Question 22

binding to plasma proteins will _______ the rate of metabolism

Answer 22

decrease

Question 23

usually, the body transforms drugs into what kind of compounds?
does the opposite ever occur?

Answer 23

usually - more polar hydrophilic inactive compounds for elimination

SOMETIMES – the opposite occurs and metabolism activates a drug

Question 24

what is the primary organ where most biotransformation/metabolism reactions take place?
explain the mechanism

Answer 24

liver

phase 1 and phase 2

Question 25

explain phase 1 metabolism reactions give an example

Answer 25

biotransformation generally results in the loss of pharmaceutical activity by the ADDITION OF A FUNCTIONAL GROUP cyt-p450 oxidizes up to 80% of all drugs

Question 26

explain phase 2 metabolism reactions

Answer 26

biotransformation is the CONJUGATION of the parent compound/phase 1 metabolite to glutathione, amino acid, sulfate, and glucuronic acid generally results in the complete inactivation of the drug

Question 27

how can drugs be excreted?

Answer 27

excreted from the body either unchanged or as metabolites

Question 28

what is the most important organ for the excretion of water-soluble drugs and metabolites

Answer 28

kidney

Question 29

renal excretion of drugs is dependent on several factors: name 4

Answer 29

-protein binding -GFR (glomerular filtration rate) -tubular secretion and reabsorption -blood flow

Question 30

oral drugs that are not absorbed by the GI tract are excreted where

Answer 30

in the feces

Question 31

some drugs and their metabolites are excreted where?

Answer 31

in the bile this is the case for drugs absorbed in the GI

Question 32

what 4 things are time course relationships?

Answer 32

latency time of onset time of peak effect duration of action

Question 33

what 4 things are dose-response relationships?

Answer 33

affinity potency efficacy dose-response curve

Question 34

define latency

Answer 34

the time between the administration and the first measurable signs of a response

Question 35

define time of onset

Answer 35

the time of the first measurable response

Question 36

define time of peak effect

Answer 36

peak effect usually occurs when the drug concentration at the site of action has reached its maximal level

Question 37

define the duration of action

Answer 37

from the time of onset to the time when the response is no longer perceptible.(OFFSET)

Question 38

duration of action depends on what 2 things

Answer 38

the dose the rate of drug removal from the site of action

Question 39

what is offset

Answer 39

the time when the response is no longer perceptible

Question 40

define the dose response curve

Answer 40

analyzes the magnitude of a drug effect by plotting the magnitude of the response as a function of dose of the drug

Question 41

the MAXIMUM EFFECT is when....

Answer 41

the dose response curve reaches a plateau

Question 42

define affinity

Answer 42

the ability of a given drug to bind with a specific receptor

Question 43

define potency

Answer 43

the dose needed to produce a response of a given intensity

Question 44

a shift to the right in the dose response curve means a _______ in potency, while a shift to the left indicates a ____ in potency

Answer 44

to the right = decrease in potency to the left = increase in potency

Question 45

define efficacy

Answer 45

the ability of the drug to produce the desired response/effect upon binding to the receptor

Question 46

efficacy describes the.......

Answer 46

maximal response that can be created by the drug

Question 47

explain ED50

Answer 47

50% effective dose the dose of a drug that produces an effect in 50% of the population (quantal) graded - the dose that causes 50% of maximal effect

Question 48

ED50 is a convenient way to do what

Answer 48

characterize a drugs and a useful way to compare DRUG POTENCY

Question 49

what is LD50

Answer 49

the dose that kills 50% of an exposed population

Question 50

what is therapeutic index

Answer 50

a measure of the drug's safety = LD50/ED50 higher value = safer drug

Question 51

barbiturates bind to what? this increases what? what is the result?

Answer 51

barbiturates bind to GABA A receptors this increases GABA-induced chloride currents results in CNS depressant effects

Question 52

barbiturates are used as what kind of drugs

Answer 52

sedatives hypnotics anesthetics anticonvulsants

Question 53

how are barbiturates classified?

Answer 53

on the basis of their duratiokn of actions ultra short short intermediate long acting

Question 54

barbiturates are schedule ----- depressants under what act?

Answer 54

schedule II, III, and IV DEA Controlled Substances Act

Question 55

explain the duration of all of the classes of barbiturates and give an example of each

Answer 55

Long acting - over 6 hours - PHENOBARBITAL Intermediate acting - 3-6 hours - AMOBARBITAL Short acting - under 3 hours - PENTOBARBITAL ultra short acting (30 mins) - THIOPENTAL

Question 56

the onset and duration of a drug are dependent on what?

Answer 56

ADME

Question 57

the onset of thiopental CNS effects is equal to what

Answer 57

the time required to reach the CNS after IV injection

Question 58

how does thiopental have such a short duration of action

Answer 58

thiopental is highly lipophilic and the brain is highly perfused and lipophilic. thus, thiopental rapidly reaches effective blood levels. HOWEVER, due to its high lipophilicity it also rapidly re-distributes into adipose and other tissues, so the blood levels decrease rapidly to subtherapeutic levels. as a result, its duration of action is ULTRA SHORT

Question 59

explain how phenoparbital and pentobarbital have a longer duration of action than thiopental

Answer 59

they are less lipophilic and thus cross the brain barrier less rapidly, and at the same time the drug is being distributed to other tissues takes longer to reach effective CNS levels