Pharmacodynamics and drug-receptor interaction Flashcards

1
Q

pharmacodynamics

A

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

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2
Q

Chemical mechanism of drug action

A

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

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3
Q

Antacids

A

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

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4
Q

Osmotic diuretics

A

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

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5
Q

chelating agents

A

drugs that chemically bind to target molecules

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6
Q

digibind

A

used as an antidote for digoxin toxicity

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7
Q

deferoxamine

A

used as an antidote for iron toxicity

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8
Q

Receptor binding

A

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

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9
Q

Agonist

A

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

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10
Q

Antagonist

A

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

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11
Q

Receptor types

A

ligand gated ion channels
GPCR
enzyme linked receptors
intracellular receptors

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12
Q

What is Kd

A

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

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13
Q

Affinity

A

strength of interaction between a ligand and its receptor

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14
Q

Kd= ?

A

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

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15
Q

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

A

affinity

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16
Q

Affinity constant

A

Ka
reciprocal of the equilibrium dissociation constant

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17
Q

Drugs with a high affinity have what kind of Kd?

A

low

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18
Q

Fraction occupancy of receptors= ?

A

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

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

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19
Q

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

A

the maximal effect

20
Q

potency

A

amount of drug needed to produce an effect

21
Q

EC50

A

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

22
Q

Efficacy

A

ability of ligand to produce a pharmacological response

23
Q

Emax

A

maximal effect of a drug

24
Q

factors that affect biological response

A

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

25
Q

intrinsic activity

A

ability of a drug to fully/partially activate the receptors

26
Q

Full agonists

A

intrinsic activity ~ 1
can produce a maximal response

27
Q

Partial Agonists

A

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

28
Q

Inverse agonists

A

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

29
Q

Competitive antagonists

A

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

30
Q

Non competitive antagonists

A

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

31
Q

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

A

right

32
Q

Which way do response curves shift in non competing antagonism?

A

right and down

33
Q

Allosteric antagonists

A

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

34
Q

ED50

A

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

35
Q

ED99

A

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

36
Q

LD50

A

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

37
Q

LD1

A

dose producing toxicity in 1% of the population

38
Q

Therapeutic index

A

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

39
Q

large therapeutic index indicates

A

a wide margin between effective dose and lethal dose

40
Q

therapeutic window

A

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

41
Q

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

A

high

42
Q

factors affecting the response to a prescribed drug dose

A

medication errors
patient compliance

43
Q

factors affecting administered dose

A

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

44
Q

factors affecting concentration at site of action

A

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

45
Q

factors affecting drug effects

A

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