Principles of pharmacology part 2

Question 1

What is pharmacodynamics?

Answer 1

The study of the interaction of drugs molecules with specific receptor

Question 2

What are receptors?

Answer 2

Proteins on the cells surface or within the cell

Question 3

What are ligand?

Answer 3

Molecules that bind to a receptor with some selectivity

Question 4

Explain how the two(Type A and Type B) principal types of receptors function?

Answer 4

Type A - is when most drugs and neurotransmitters remain outside the cell and bind to receptors on the exterior cell surface.

Type B - is when hormones are capable of entering the cell before acting on an intracellular receptor

Question 5

Explain the function of a Type A receptor

Answer 5

When these receptors are activated, they initiate changes in an effector, causing intracellular changes such as movement of ions or changes in enzyme activity

Question 6

Explain the function of Type B receptor

Answer 6

changes the expression of specific genes within the nucleus. which then causes altered proteins synthesis which changes the cells function

Question 7

with respect to receptors, what is the difference between affinity and efficacy?

Answer 7

affinity describes the fit of the molecule to the receptor

efficacy describes if the fit produces a significant biological response

Question 8

Explain the differences between Receptor agonist and Receptor antagonist, partial agonist, inverse agonist, and partially inverse agonist.

Answer 8

Receptor agonists have a high affinity for a receptor; bind to receptor and initiate a cellular response.

partial agonist have intermediate efficacy

Receptor antagonists bind to receptor but produce no
effects (low efficacy); also prevent agonists from binding

Inverse agonists initiate an action opposite to that produced by an agonist.

partial inverse agonist have intermediate opposite effect

Question 9

what is up-regulation?

Answer 9

when receptor numbers increase

Question 10

what is down-regulation?

Answer 10

when receptors are reduced in number

Question 11

when there is increased number of receptors, what happens?

Answer 11

chronic use of receptors

Question 12

when there is a decrease number of receptors

Answer 12

chronic activation of the receptors

Question 13

what does does-response curve describe?

Answer 13

describes the receptor activity and the extent of biological or behavioral effect produced by a given drug concentration (dose).

Question 14

what is 50% effective dose (ED50)?

Answer 14

the dose that produces half the maximal effect

Question 15

with respect to the dose-response curve, what is the threshold?

Answer 15

dose that produces the smallest measurable response.

Question 16

what is potency?

Answer 16

amount(ex. mg of morphine) of drug necessary to produce a specific effect

Question 17

what does comparing ED50 of different drugs show? give an example.

Answer 17

shows differences in potency(effect), even if they have identical efficacy.

for example, it takes more of a dose in morphine(10mg) to reach ED50, compared to hydromorphone(1mg)

Question 18

what does comparing ED50 of different drugs show? give an example.

Answer 18

shows differences in potency, even if they have identical efficacy.

for example, it takes more of a dose in morphine(10mg) to reach ED50, compared to hydromorphone(1mg)

Question 19

what is Efficacy?

Answer 19

the extent to which a ligand-receptor binding initiates a
biological action (e.g., the ability of an agonist to activate its receptor)

Question 20

with respects to the dose-response curves for four analgesic agents. what similarities do you notice when you compare hydromorphone, morphine, and codeine

Answer 20

The linear portions of the curves for the opiate analgesics are parallel, suggesting that they work through the same mechanism

Question 21

with respects to the dose-response curves for four analgesic agents. what DIFFERENCES do you notice when you compare hydromorphone, morphine, and codeine to aspirin

Answer 21

Aspirin is not an opiate and relieves pain by a very different mechanism of action, so the shape of the curve is distinct. In addition, the maximum effectiveness of aspirin never reaches the level of the opiates

Question 22

what should you do in a therapeutic situation?

Answer 22

Undesirable or dangerous side effects of a drug must be evaluated carefully

Question 23

what is TD50?

Answer 23

dose at which 50% of the POPULATION experiences a toxic effect.

Question 24

what does comparing TD50 with ED50 helps determine?

Answer 24

appropriate doses to prevent toxic effects.

Question 25

how do you compare TD50 with ED50?

Answer 25

using the Therapeutic index (TI) = TD50/ED50

Question 26

how do you know if a drug is safe using the Therapeutic index?

Answer 26

if the index is a larger number

Question 27

describe the Therapeutic index for anxiety. explain ED50 and TD50 with respect to anxiety.

Answer 27

ED50 for relieving anxiety (i.e., the dose at which 50% of the population shows reduced anxiety)

TD50 (the dose at which 50% of the population experiences a particular toxic effect) for respiratory depression

Question 28

how do you know you have a safe Therapeutic index?

Answer 28

If the toxic does (TD50) is much higher than the pain relief does (ED50)

then it is safe. in other words, you have a large TI, such that, it would be TD50/ED50 > 1

Question 29

what is a Competitive antagonists?

Answer 29

compete with agonists to bind receptors but don’t initiate effects, reducing effect of the agonist.

Question 30

what can take over competitive antagonist?

Answer 30

Can be displaced by an excess of agonist.

Question 31

what does Noncompetitive antagonists do? visualize a graph and explain why?

Answer 31

reduce effect of agonists in other
ways. this is seen when the curve looks completely different. which is why its assumed it changes it a different way.

Question 32

what are similarities in both competitive antagonist and antagonist?

Answer 32

regardless of the increase in morphine, the maximum efficacy is never reached

Question 33

what does physiological antagonism mean?

Answer 33

Physiological antagonism results when two drugs produce opposite effects and reduce each other’s effectiveness

Question 34

what is additive effects?

Answer 34

seen when the combined drug effect equals the sum of each drug alone

Question 35

what is potentiation?

Answer 35

the combination of two drugs produces effects
greater than the sum of their individual effects

Question 36

how does tolerance occur?

Answer 36

Repeated drug exposure

Question 37

what is tolerance?

Answer 37

a diminished response – increasingly larger doses must be administered to obtain the same magnitude of response

Question 38

what is cross tolerance? Give an example

Answer 38

tolerance to one drug can diminish effectiveness
of a second drug

If an individual used drug B chronically, then when using Drug A they realize they don’t feel anything

Question 39

What are three types of tolerances?

Answer 39

1. metabolic
   2.pharmacodynamic
   3.behavioral

Question 40

how does metabolic drug occur?

Answer 40

the repeated use of the drugs increase their own rate of metabolism by liver microsomal enzyme induction

Question 41

how does pharmacodynamic tolerance occur?

Answer 41

neural function changes to adapt to continued
presence of the drug by down-regulation.

Question 42

what is behavioral tolerance?

Answer 42

tolerance created when the individual uses the drug in the same environment in which the drug was
before administered

Question 43

Give an example of classical conditioning of drug-related cues

Answer 43

when the equipment of drug used elicits a drug effect without the use of the drug. this is due to the conditioning

Question 44

what drugs or drug classes cause metabolic tolerance?

Answer 44

(BAM)Barbiturates, Alcohol, and morphine

Question 45

what drugs or drug classes cause pharmacodynamic tolerance?

Answer 45

( C CAN BAM LSD). all of the above. Barbiturates, Alcohol, morphine, amphetamine, cocaine, caffeine, nicotine, and LSF

Question 46

what drugs or drug classes cause behavioral tolerance?

Answer 46

(BAMAC) Barbiturates, Alcohol, morphine, amphetamine, cocaine. however, caffeine and nicotine have mixed tolerance.

Question 47

What is sensitization?

Answer 47

reverse tolerance: enhancement of drug effects
after repeated administration of the same dose drug

Question 48

What is Cross-sensitization?

Answer 48

enhancement of drug effects occurs because of another drug