introduction to pharmacology and therapeutics (2)

Question 1

what is a drug?

Answer 1

External substance that acts on living tissue to produce a measurable change in the function of that tissue

Question 2

what are the types of drugs used in dentistry?

Answer 2

• Local anaesthetic
○ Prevents pain
○ Blocks nerves so interrupts communication
• Antimicrobials
○ Treat and prevent infections
• Anxiolytics
○ Reduce anxiety
• Analgesics
Reduce postoperative pain
many medical drugs may also affect dental care

Question 3

what can drugs do

Answer 3

• Stimulate normal body communications
○ Eg: adrenaline will go through blood stream and cause firing of receptors = increases rate and force of cardiac activity
• Interrupt normal body communications
○ Eg: LA blocks nerves to disrupt communication
• Act on non-host organisms to aid body defences
Can slow down microorganisms to contain it enough until body’s defence system can destroy them

Question 4

what are the 2 types of host communication

Answer 4

• hormone messages
  > general info to all tissues
• neural messages
  > targeted info for specific tissues

both use chemical messengers
hormones are chemical messengers
nerves are sent by chemical messengers

Question 5

name 4 relevant hormones

Answer 5

insulin
cortisol
sex hormones
thyroid hormones

Question 6

what is hyperthyroidism

Answer 6

having too much thyroid hormone

• sweating, anxious, hot
• bulging eyes

Question 7

what is hypothyroidism

Answer 7

too little thyroid hormone

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

Question 8

what is the thyroxine tablet

Answer 8

Medicine give to patient to replace hormone not working
- Hormone T3 or T4

Dose adjusted to correct level gradually

Acts directly in the tissues
□ No direct effect on thyroid gland

Hormone replacement therapy

Question 9

i cant think of a question for this one and dont fully understand it but feel it is important to know so this is the flashcard for this lol sorry
to do with nerve communications

Answer 9

• Autonomic nervous system
○ Sympathetic
§ Epinephrine
○ Parasympathetic
§ Acetylcholine
□ Muscuranic cholinergic transmission
Blocking it will prevent saliva flow

Question 10

explain nerve control of heart rate

Answer 10

○ Sympathetic - Adrenergic stimulation
§ Speeds up the heart via Beta-receptors
○ Parasympathetic - cholinergic stimulation
§ Slows the heart via cholinergic receptors

Question 11

name 2 autonomic drugs and explain their functions

Answer 11

• Epinephrine (beta agonist)
○ Increases heart rate = stimulates receptors
• Atenolol (beta blocker)
Decreases heart rate = medicine to block
stimulation

Question 12

how is the heart rate kept low at rest?

Answer 12

kept low by the cholinergic system

• Pilocarpine (cholinergic agonist)
• Atropine (cholinergic blocker)
○ Blocks receptors to increase heart rate

Question 13

what can receptors be coupled to?

Answer 13

ion channels
g-proteins
enzymes
gene transcription

Question 14

how do receptors work?

Answer 14

they pick up the drug and cause a change
usually extends to outside of cell and brings the drug within
always coupled to something in a cell

Question 15

when a drug interacts with a receptor, what are the 4 things that can occur as a result?

Answer 15

1) Drug doesn’t fit so nothing happens
2) Drug does fit but not well enough to cause a change
(Blocker)
3) Does fit and causes change to allow affect to happen
(Agonist Bind to a receptor and causes an effect)
4) Does bind but doesn’t change shape so nothing else can bind
(Antagonist)

Question 16

what is an agonist?

Answer 16

a substance which initiates a physiological response when combined with a receptor.

Question 17

what is an antagonist?

Answer 17

a substance which interferes with or inhibits the physiological action of another

Question 18

what is a reversible antagonist?

Answer 18

when the effect of the antagonist is reduced by increasing the concentration of the agonist
eg Atenolol

Question 19

what is an irreversible antagonist?

Answer 19

one that binds to a receptor meaning it is not available for the agonist to attach to
eg Phenoxybenzamine

Question 20

what is a partial agonist?

Answer 20

drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist
ie they cause the response of the agonist but not to the full extent

Question 21

what is affinity

Answer 21

how attracted drug and receptor are to each other

Question 22

what is occupancy

Answer 22

time drugs are together with receptor

Question 23

what is efficacy

Answer 23

how effective drug is in producing the change you want

Question 24

explain what is meant by the ‘law of mass action’

Answer 24

More drug around receptor means more will bind to receptors

a drug in the vicinity of a receptor will obey this law

Question 25

how do enzymes work

Answer 25

• Substrate binds to enzyme active site
• Forms enzyme / substrate complex
• Then forms enzyme / products complex 
	○ Alter reactions
• Products then leave the active site of the enzyme
• There is no change to the enzyme

makes changes without energy
can be reversible and irreversible

Question 26

what do ion channels do?

Answer 26

• Disrupt cell ion balance
○ Ion influx
§ As electrical polarisation changes it flips stable ion channels to allow ion through
○ Electrical activity

Question 27

can both agonists and antagonists be competitive?

Answer 27

yes

Question 28

what affects efficacy?

Answer 28

occupancy and affinity

Question 29

what do drugs act through?

Answer 29

○ Receptors on cells
○ Influencing enzyme action
○ Disruption of ion conduction channels