Drugs in Health and Disease

Question 1

What is a drug?

Answer 1

A drug is an external substance that acts on living tissue to produce a measurable change in the function of that tissue

Question 2

What are the side effects?

Answer 2

they are the effects of the drug that are not what we are clinically wanting

Question 3

what is the importance of knowing side effects

Answer 3

we can assess the advantages and disadvantages of the drug when prescribing to a patient

Question 4

what are the drugs commonly used in dentistry

Answer 4

local anesthetic
antimicrobials
anxiolytics
analgesics

Question 5

why is it important to know what drugs patients are on

Answer 5

the drugs that medical doctors are giving may interfere with the treatment that we are giving the patient

Question 6

what are the three ultimate effects of drugs

Answer 6

stimulate normal body communications
interrupt normal body communications
act on non-host organisms to aid body defenses

Question 7

what is an example of a drug that we use in dentistry that interrupts normal body communications

Answer 7

local anaesthetic can block nerves which interrupts the communication between nervous tissues and the brain

Question 8

what do we mean when we say that drugs act on non host organisms to aid body defenses

Answer 8

The antibiotic contains the microorganism enough so that the body can deal with it.

Question 9

how does the body communicate to itself

Answer 9

hormone messages - general info to all tissues

neural messages - targeted info for specific tissues

Question 10

What do the thyroid hormones do

Answer 10

balance the body’s metabolism

Question 11

what is too much thyroid hormone

Answer 11

hyperthyroidism

Question 12

what is too little thyroid hormone

Answer 12

hypothyroidism

Question 13

what can hypothyroidism result in

Answer 13

cold intolerant
slow mentation
hair loss
slow pulse and low blood pressure

Question 14

how do we treat hypothyroidism

Answer 14

hormone replacement therapy
replace missing t3 and t4
dose adjusted to correct level gradually
acts directly in the tissues - no direct effect on the thyroid gland

Question 15

what are the effects of the sympathetic nervous system on the heart

Answer 15

adrenergic stimulation

speeds up the heart via beta receptors

Question 16

what are the effects of parasympathetic nervous system on the heart

Answer 16

cholinergic stimulation

slows the heart via cholinergenic receptors

Question 17

what are the autonomic drugs

Answer 17

epinephrine
atenolol
pilocarpine
atropine

Question 18

what does epinephrine do

Answer 18

beta agonist

speed up heart rate by stimulating receptor

Question 19

what does atenolol do

Answer 19

beat blocker

slows down heart rate by preventing normal hormone from stimulating receptor by blocking it

Question 20

what does pilocarpine do

Answer 20

it is a cholinergic agonist

keeps heart rate at rest artificially low

Question 21

what does atropine do

Answer 21

cholinergic blocker

Question 22

what do drugs interact with tissues through

Answer 22

receptors
enzymes
ion channels

Question 23

what happens when a receptor binds to its target

Answer 23

causes a change throughout the membrane

this causes the protein to change shape which follows through onto the ion channel changing its shape

Question 24

why do proteins change shape on binding

Answer 24

to adopt lowest energy state

be as electrical neural as they can be

Question 25

what are the 2 possible effects of drug interacting

Answer 25

1. The drug doesn’t fit well enough that the protein doesn’t change shape, the drug has no effect and so blocks the receptor from binding to anything else - antagonist
2. Drug binds to receptor site and makes protein change its shape which allows advantageous effect – agonist

Question 26

what is affinity

Answer 26

how keen the drug is to stick to the receptor - the higher the affinity the longer the drug will be on the receptor

Question 27

what is occupancy

Answer 27

the time the drug and receptor are stuck together

Question 28

what is efficacy

Answer 28

how effective is the drug at giving the change that you want to see

Question 29

what is amount of receptors occupied at one time depend on

Answer 29

affinity of the drug

concentration of the drug

Question 30

what do partial agonists do

Answer 30

they bind to receptor

more difficult to produce an effect

Question 31

how can the efficiency of partial agonists be improved

Answer 31

increasing concentration but this only works for some

Question 32

what are the different types of antagonists

Answer 32

can be competitive and non competitive

can be reversible or irreversible

Question 33

what is a reversible antagonist

Answer 33

the antagonist effect is reduced by increasing the concentration of the agonist

Question 34

what is an irreversible antagonist

Answer 34

Binds and reduces available receptors for the agonist

Question 35

what is an example of a reversible antagonist

Answer 35

atenolol - beta1 blocker

Question 36

what is an example of an irreversible antagonist

Answer 36

phenoxybenzamine - alpha 1 blocker

Question 37

how can we block enzyme action

Answer 37

by blocking the receptor or blocking the shape of the enzyme

Question 38

what do ion channels do

Answer 38

they disrupt ion cell balance though electrical activity and ion influx

Question 39

what is the first way ion channels work

Answer 39

receptor has a signaling molecule which causes a change in the cell which causes a change in the transmemebrane protein which causes a hole which allows ions through

Question 40

what is the second way ion channels work

Answer 40

Here the ion channel has no receptor binding agonist and causing a change inside the cell
It is instead electrically polarized
Electrical polarization causes the ion channel to allow ions to flow through in the resting state the channel is closed, and the resting position is closed
Action potentials reverse the polarity of the nerve tissue which causes a change in the shape of the ion channel which opens it allowing the sodium ions to flow in