Pharmacology Flashcards
1
Q
what is meant by an agonist drug?
A
binds to and activates receptors to produce a biological response.
2
Q
what is meant by an antagonist drug?/
A
blocks the action of agonists from stimulating receptors.
3
Q
what is meant by pharmacokinetics?
A
how the drug is absorbed, distributed, metabolized or excreted.
What the body does with the drug.
4
Q
how do drugs work in the body?
A
they act by binding to receptors causing either activation or inhabition of a regualr body process to give a biological response.
5
Q
what is meant by pharmacodynamics?
A
what the drug does to the body. - physiological effects on the bosy and the mechanisms of the drug action/ the relationship between drug concentration and effect.
6
Q
why do drugs target receptors?
A
becuase receptors coordinate the function of all cells in the body. They are chemical messengers.
7
Q
what would an agonist drug do to a receptrs?
A
activate the receptor.
8
Q
what would an antagonist drug do to a receptor
A
block the receptor.
9
Q
why do drugs target ion channels?
A
becuase they are gateways into the cell.
10
Q
what do blocker drugs do to ion channels?
A
block the channel.
11
Q
what do modulator drugs doe to ion channels?
A
increase or decrease opening probability.
12
Q
why do drugs target enzymes?
A
because often the drug molecule is a substrate analogue that acts as a competitive inhibitor of the enzyme.
13
Q
what effect does an inhibitor drug have on enzymes?
A
normal reaction inhibited.
14
Q
what effect does a false substrate drug have on enzymes?
A
abnormal metabolite produced.
15
Q
what effect does a prodrug have on enzymes?
A
active drug roduced.
16
Q
why do drugs target transporters?
A
because they transport the movement of ions ad small organic molecules across cell memebranes.
17
Q
what effect do inhibitor drugs have on transporters?
A
block transport.
18
Q
what effect do false substrate drugs have on transporters?
A
abnormal compound accumulated.
19
Q
with Pharmacokinetics what 2 assumptions need to be made?
A
- plasma concentration bears a precise relation to the concentration of drug in the immediate environment of its target.
- drug response depends only on the concentration of the drug on the immediate environment of its target.
20
Q
what type of pain is most likely to bring a pt to the dentist?
A
acute pain.
21
Q
what are corticosteriod medications used for?
A
used for inflammation to relieve discomfort and redness of the mouth.
22
Q
what are narcotic analgesic medicationd given for?
A
may be given for severe pain conditions.
23
Q
what is codeine metabolised by?
A
CYP2D6
24
Q
what are the effects of Nitrous oxide?
A
- tingling sensation
- warm sensation
- feeling of euphoria
- sleepiness
25
what are the 2 sedation drugs commonly used in dentistry?
- Nitrous oxide
| - midazolam
26
what is a problem with midazolam if it is used with other CNS depressants?
can increase possibility of hypotention, respiratory depression/arrest and death.
27
what is metronidazole used for? (types of bacteria)
anaerobic bacteria and protozoa
28
what are the effects of prolonged use of antibiotics?
- normal oral/gut flora is destroyed.
- selection of resistant strains.
- colonisation by harmful microbes that are not normal residents.
29
what side effects to the oral cavity can antidepressants have?
dry mouth.
30
How effects do anti-depressants have on the body?
block the action of neurotransmitter acetylcholine.
31
what side effects do nitrates have on the body?
can cause headaches.
32
what are nitrates given to patients?
used to prevent and reliece chest pains (angina) as they are vasodilators.
33
what effects do antihypertensives have on the body?
prevent postural hypotension (excessive fall in BP when moving in to an upright position)
34
what kind of behaviour would you often seen in patients taking opiods?
addictive-related behaviour.
| often have poor dental health due to neglect.
35
patients taking insulin are at higher risk of what?
dry mouth, gum inflamation, poor healing of oral tissues and thrush.
36
what medical emergency is most likely to happen with a patient taking insulin?
hypoglycaemic episode - severe decline in blood glucose levels.
37
what are patients taking steriods at a higher risk of complications?
- adrenal suppression caused by steroid therapy.
- disease/condition which requires them to take steroids.
- oral yeast infections and blood blister (if chronic user)
38
why can lidocain not be given to patients taking Beta blockers?
as beta blockers can decrease hepatic blood flow and/or inhibit hapatic enzymes, this reduces metabolism of lidocain. Leading to increased serum levels and possible toxicity of lidocain.
so taking both lidocain and beat blockers can result in myocardial depression.
39
what is the effect of beat blockers on the body?
block sympathetic influences on cardiac B1 adrenoreceptors.
40
why can patient taking beta blockers not be given vasosupressors in LA?
due to non-selective beta-blockers patient has hightened sensitivity to the systemic effects of vasosupressors. so they are at a high risk of an acute hypertensive episode.
41
if a patient is taking monoamine oxidase ihhibitors why can they not have La with a wasoconstrictor?
could cause acute hypertensive crisis.
42
why are the effects of warfrin and antiplatelet drugs on patient?
they are anticoagulants. So they inhibit the synthesis of vit K-dependent coagulation factors.
43
what should be the normal INR for a patient?
1
44
what are the risks to warfarin patients if their INR rises above 1?
increased risk of bleeding.
45
how soon before treatment should an IRN be taken?
at least 72 hours before.
46
why would a patient be taking bisphosponates?
prevent bone resorption in osteoporosis and bone cancer.
47
what can be a problem with patients taking bisphosponates with surgery?
impaired wound healing.
48
why can suppressing bone resorption due to taking bisphosponates become a problem to bone?
any damaged bone will be left in situ instead of being resorbed.
49
what are the effects of Stevens-Johnson Syndrome?
Hypersensitivity complex - effects the skin and mucous membrane.
- ulcers and other lesions appear in the mucous membrane.
- extremely painful and reduces the patient ability to eat and drink.
50
How does LA work in the body?
- reversible blocking of nerve conduction.
- blocks entry of sodium ions into cell.
- memebrane expansion theory.
- specific binding hypothersis.
51
what are the 3 different types of LA?
- Ester based
- Amino-amides
- Articaine.
52
what is an example of an ester based La?
Procaine and benzocaine.
53
what are some examples of an amino-amide LA?
- Lidocaine
- Mepivocaine
- Prilocain
- Bupivocaine.
54
why do you have to be careful when using amino-amids LA with a patient with liver disease?
because amino-amids are metabolised by the liver and excreted via the kidneys.
55
what are the benefits of using a vasoconstrictor in LA?
- increases duration of action via reducing LA systemic absorption and increasing anaesthetic concentration near nerve fibres.
- reduce plasma levels - reducing the dose of LA required.
56
what are some examples of vasoconstrictos used in LA?
adrenalin/epinephrine and felypressin.
57
patients with what conditions should you be careful when using adrenalin/epinephrine?
patients with heart disease, hypertension and unstable angina.
58
For what patients should you not use felypressin and why?
pregnant patients because it can induce labour.
59
what LA causes vasoconstriction?
bupivacain.
60
How can you maximise LA effectiveness?
- use of topical
- good technique
- careful puncture
- explain sensation.
- good communication
- solution at room temp.
- stretch tissues
- slow injection.
61
What types of topical are used in dentistry?
- Xylonor gell (5% lidocain)
- 20% Benzocaine
- Lidocain 4% ointment or gel
- 10% lidocaine intraoral sray.
62
How many cartridges can an Adult be given of 2% lidocain LA?
7x 2.2ml.
63
How many cartridges can an child be given of 2% lidocain LA?
2x 2.2 ml
64
How many cartridges can an Adult be given of 4% articaine LA?
5x 2.2ml
65
How many cartridges can an child be given of 4% articaine LA?
2x 2.2ml.
66
How much do you reduce LA dosage by for elderly (65+) patients?
reduce by 50%
67
why do you reduce LA does for elderly patients?
due to liver function decreasing with age.
68
what actions should you take before giving any patient with liver damage La?
contact their GP regarding liver function tests.
69
what are other ways in which you can locally anestise an area without LA drugs?
- cooling with ethyl chloride
- pressure
- hypoxia
70
what are the different methods of LA using drugs?
- topical applcation
- subcutaheous injection (inflitration)
- nerve block
- epidural
- intrathecal (in spine)
71
what are the idea properties of LA?
- stabel in solution
- non-irritating to tissues
- no permanent damage
- no allergic response
- rapid onset of action
- predictable duration of action
- more of sensory block.
- no systemic toxicity
- potent
- no active metabolites.
72
why in LA is the aromatic terminal essential?
allows the LA to penetrate fatty tissues.
73
why does LA need to penetrate through fatty tissues?
to gain access to the nerve cell membrane through the lipid sheath to allow it to reach its site of action,
74
why in LA is the hydrophilic amino terminal needed?
at certain pH it can gain a charge enhancing solubility in water and prohibit its solubility into lipids.
75
what is LA solubility in water important?
- to allow for the dissolution in a solvent to permit injection.
- allow penetration through body fluid following administration.
76
what is different about the structre of articaine when compared to both amide and ester LAs?
articaine contains both an amide with an ester side chain.
77
what is an example of a ketone-type agent?
Dyclonine (a liquid topical applied with a swab or as a mouth rinse- has bactericidal and fungicidal properties)
78
what is the pKa value of LA between?
8.0-9.0
79
at pH 7.4 what percentage of LA will be in the non-ironized form?
5-20%
80
how is the non-ironizing form of LA important?
allows for rapid penetration of cell membrane.
81
how is the ironizing form of LA important?
once LA has diffused into the nerve trunk - the ionized form binds to the sodium channels/
82
what does pKa indicate?
the pH at which the ionized and non-ironized forms of LA are equal.
83
what are the major determinants of an LA drug allowing for diffusion into nerve fibres?
- pKa
- lipid solubility
- pathophysiological factor (eg inflammation etc)
84
what types of nerves are most sensitive to LA?
ones with a smaller diameter and that are also myelinated.
85
what type of channels do sodium channel blockers bind to? and why?
activated ones -so that LA only works where it needs to.
86
what is the only type of LA that binds to any sodium channel?
Benzocain
87
what are the effects of injecting LA into an area with acidosis? and why?
will partly reduce the action of LA - this is due to most La's being ironized therefor unable to cross the cell membrane.
88
what is acidosis? and when is it likely to occur?
it is an icrease acidity of blood plasma, and happens with inflamation.
89
at what pH does blood plasma need to be at for acidosis?
less than 7.35
90
at what pH does blood plasma need to be at for alkalosis?
more than 7.45
91
what is nerve blockage dependent upon? (in regards to the nerves themselves)
- length of axon (short)
- frequency dependence (resting nerves are less sensitive)
- nerve fibre size (small and myelinated)
- arrangement of fibre bundles in nerve sheath.
92
what are some of the side effects of LA toxicity?
- hypersensitivity (allergic response)
- unconsciousness/respiratory arrest (due to CNS depressant)
- circulatory collapse (due to possible decrease in cardiac output)
- methaemoglobinaemia (toxic efffect of prilocaine/articaine in high does)
93
How much epinephrine (adrenaline) is normally found in LA?
1:200,000
94
how much norepinephrine (norarrenaline) is normally found in LA?
1:100,000
95
why are vasoconstrictors not used in LA when injected into extremities (ie fingers and toes)?
because it limits circulation, and there is a higher risk of hypoxia of tissues.
96
why would adrenaline be used over felypressin as a vasoconstrictor?
because it is more effective at constricting blood vessels.
97
why would felypressin be used over adrenaline as a vasoconstrictor?
because it has no effect on the heart conduction / contraction.
