Clinical Pharmacology Flashcards

(91 cards)

1
Q

What are drug categories in dentistry an what is their role?

A

Local anaesthetic - Prevent pain!

Antimicrobials -Treat and prevent infections

Anxiolytics - Reduce anxiety

Analgesics - Reduce postoperative pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the types of host communication?

A

Hormone messages
- General information to ALL tissues

Neural messages
- Targeted information for SPECIFIC tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are examples of hormone systems in the body?

A

Thyroid Hormones – T3 & T4

Insulin/glucagon

Cortisol/Aldosterone

Sex Hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do thyroid hormones do?

A

balance body’s metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can hypothryroidism be treated?

A

Drugs can replace the missing active hormone - T3 & T4

Thyroxine dose adjusted to correct level gradually

Replacement medicine acts directly in the TISSUES, no direct effect on thyroid gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the automomic nervous system communicate? (what types)

A

Sympathetic - Adrenaline

Parasympathetic - Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does the sympathetic system speed up heart rate?

A

Sympathetic - adrenergic stimulation

Speeds up the heart via Beta-receptors (B1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the parasympathetic system slow down heart rate?

A

Parasympathetic – cholinergic stimulation

Slows the heart via cholinergic receptors (M2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are examples of autonomic drugs?

A

Adrenaline (beta agonist)
Atenolol (beta blocker)

Pilocarpine (cholinergic agonist)
Atropine (cholinergic blocker)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the routes of administration?

A

Transdermal - drug applied to the skin for adsorption

Subcutaneous - drug injected into the tissues of the skin

Intramuscular - drug injected into muscle

Intravenous - drug injected into a vein

Transmucosal - drug applied to the mucosa for adsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a drug applied to the tissue where it acts called?

A

topical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a drug applied to the whole organism called?

A

systemic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the main purpose of aspirin and what side effect is also useful?

A

aspirin reduces pain (NSAIDS)

side effect - platelet inhibitor for heart attacks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What reaction is commonly seen in penicillan allergy?

A

mild maculopapular rash

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens in anaphylaxis?

A

Swelling of tissues
narrowing of airways
leadings to circulatory failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are drug interactions?

A

One Drug interferes with the absorption, action or metabolism of another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What drugs have interactions commonly in dentistry?

A

warfarins and NSAIDs (aspirin)

protein bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is another example where warfarin interacts with another medication?

A

warfarin and erythromycin/ fluconazole/ carbamazepine

decreases drug metabolism of warfarin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What can acute toxic reactions lead to?

A

Bone marrow suppression

Hepatotoxicity & biliary stasis

Acute nephrotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What should be considering before prescirbing?

A

would a different treatment be a better option? (surgery, filling)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can prescribing the wrong drug cause?

A

ADR - adverse drug reaction

ineffective

less effective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When is the prescription valid for?

A

six months from date issued

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is different for private prescriptions?

A

GDC number added instead of NHS list number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are advantages of written instructions?

A

Stressed patient may not remember instructions

Language issues may prevent proper understanding
Multilingual options, large print options

Contact number for Patient if Issues arise with the medicine

Legal protection if post-treatment course questioned

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What should advice to patients be?
Take drugs at correct time and finish the course Unexpected reactions: STOP! and contact prescriber Known side-effects should be discussed e.g. Metronidazole and alcohol Keep medicines safe: especially from children
26
Where can dentists refer to regarding drugs?
BNF SDCEP
27
What are the 4 modes of action?
Activation or blocking of Receptors Activating or blocking Enzyme function Opening or blocking Ion Channels Facilitation or blocking Transport systems
28
What is the difference between antagonist and agonist and inverse agonist?
* **Agonist:** Increases activity above baseline. * **Inverse Agonist:** Decreases (already present) activity below baseline. * **Antagonist:** Blocks the effects of both agonists and inverse agonists, but has no effect on its own.
29
Why is the drug/receptor interaction not enough?
a cascade is required which happens due to the conformational changes in transmembrane proteins
30
What is the effect of the drug determined by?
Affinity – the tightness of the drug binding to the receptor Occupancy – how much time the drug spends on the receptor Efficacy – how effective the drug is at producing a response from the receptor
31
What is the drug at an equilibrium with?
with surrounding tissue fluid it spends time in receptor and in fluid
32
What does a low affinity in turn cause?
low occupancy > low effect
33
What can a low affinity be combated by?
increasing the dose of the drug however in some drugs even increasing the concentration will not acheive max efficacy (partial agonist)
34
Why is butyrylcholine (BCh) a partial agonist?
max effect will never be obtained despite the concentration
35
What law do drugs in vicinity of a receptor obey?
law of mass action
36
What is a non-linear relationship between occupancy and response?
an increase in occupancy may not have an effect on the response to the drugs, ie. at half occupancy reponse could be max
37
What is the linear relationship between occupancy and response?
50% receptor occupancy produces 50% response
38
What are partial agonists?
More difficult to produce the drug/receptor effect than with an agonist Increase partial agonist concentration will improve efficacy for some receptors but not for others
39
How are competitive antagonists improved?
by increasing the concentrations (bind to more sites, inhibiting more responses)
40
What is the basis of non-competitive antagonists?
attaches to seperate site, cannot be improved with concentration affinity/efficacy rules do not apply
41
What is the difference between competitive and non-competitve antagonists?
Reversible (competitive) Agonist effect reduced by increasing the concentration of the antagonist Irreversible (non- competitive) Binds to allosteric site and reduces available receptors for the agonist
42
What temperature do enzymes work optimally at?
at body temperature (37-40)
43
Do enzymes change at the end of a reaction?
no
44
How can drugs change enzyme action?
Substrate antagonism – competitive Non-competitive substrate inhibition
45
What is an example of a non-competitive antagonist?
aspirin - platelet plug inhibitor
46
What can ion channel effects change?
cell electrical activity ion influx
47
What are examples of ion channel drugs?
LA Anti-diabetic drugs
48
Can agonists be competitive?
yes competing against the antagonist
49
What is pharmacokinetics?
what the body does to drugs
50
What is pharmacodynamics?
what drugs do to the body
51
What is the stages of a drug in the body?
Administration Absorption Transport Clinical Effect Metabolism Excretion
52
What are the enteral (via the gut) ways of administration?
oral
53
What are the parenteral (not the gut) ways of administration?
Transdermal Transmucosal Intravenous (iv) Intramuscular (im) Subcutaneous (sc)
54
What is another way of administration?
inhalation
55
What are the advantages and disadvantages of oral drug administration?
**Advantages:** * Convenient and easy to take yourself (no needles!) * Often inexpensive **Disadvantages:** * May not be absorbed well or broken down by stomach acid * Slower onset of action than some methods * First pass metabolism
56
What is the 'first pass' metabolism?
GI blood goes through the liver first ( hepatic portal vein) for metabolism (can inactivate or activate a drug) Then reaches systemic circulation after passing the liver
57
What veins do not drain to the hepatic portal vein and straight into the systemic circulation?
sublingual and rectal
58
What are the two ways the liver metabolises the drug and what are examples of both?
Inactivation: This is the more common scenario. The liver's enzymes often work to break down drugs into inactive metabolites, essentially rendering them ineffective. - More is needed via oral route to make them effective (GTN administered sublingually for angina) Activation: In some cases, the liver can actually convert an inactive prodrug into its active form. Prodrugs are essentially medications designed to be delivered safely but need liver metabolism to become effective. (Lisinopril, a blood pressure medication, is a prodrug. The liver converts it to lisinoprilat, the active form that lowers blood pressure.)
59
What are the advantages and disadvantages of intravenous/intramuscular administration?
Advantages Very rapid onset Predictable plasma levels No first pass metabolism Disadvantages Allergic reactions more severe Short duration of action Access difficulties/self-medication (patients may feel uncomfortable) Drug cost higher (purity is important)
60
What are the advantages and disadvantages of transdermal and subcutaneous administration?
Advantages No first pass metabolism Allergic reactions often very localised Prolonged action – can be days with transdermal patches (insulin) Disadvantages Very slow onset (low blood flow) Self-medication possible Drug cost higher Effect will vary from person to person and site to site
61
What method of administration gives the highest bioavailability?
intravenous
62
What is the bioavailability modified by?
Dosage form Route of administration Destruction in the gut Poor absorption First pass metabolism
63
How is the drug distributed and how can drug interactions occur?
Drug is dissolved in the blood and transported bound to carriers Usually plasma protein – Albumin Drug binding to plasma proteins Bound drug is inactive Can act as a reservoir Drug interactions possible by competitive binding i.e. Warfarin & aspirin
64
What plasma protein usually transports drugs?
albumin
65
What does the speed of diffusion depend on?
the blood flow to the area the blood wall vessel barrier active secretion of the drug into the tissue
66
single VS two compartment model
* **Single compartment:** Assumes the drug distributes evenly throughout the body like one big bucket. * **Two compartment:** More realistic, considers the drug moving between a central compartment (blood, organs- heart/brain/kidney) and a peripheral compartment (muscle, fat).
67
What is the volume of distribution?
Different parts of the body may receive different drug levels compared with plasma – ‘Compartment model’ Vascular, tissues, CNS
68
What happens if drugs bind to lipids in the tissues and what are examples?
Slow release from accumulation – prolonged effect Examples include the anaesthetic gasses – halothane, isofluorane
69
Where are drugs metabolised?
liver mostly some in plasma (some LAs)
70
What are the Phase 1 reactions and what are examples of them?
Change to drug itself Examples - Oxidation, reduction, hydrolysis
71
What are the phase 2 reactions and what are examples of them?
Conjugation to a compound scheduled for excretion Examples - Glucuronidation, sulphation, methylation, acetylation,
72
What system is used most commonly to remove substances in the body and what can affect drugs trying to leave?
P450 Mono-Oxygenase system drugs may enter competition with other substances/drugs at any step (why knowledge of drug interactions is important)
73
What can the elimination system produce that is unwarranted?
produce metabolites that are active, more potent drugs
74
How are drugs eliminated?
any body fluid i.e concentration in saliva will mirror concentration in plasma (drug and alchohol testing by police)
75
Where does the most extensive excretion occur?
Renal excretion of water soluble metabolites – urine Liver metabolism and excretion – bile Lungs – inhaled gases and volatile fractions of other drugs
76
Where do small proportions (relative to plasma concentration) get excreted?
sweat saliva tears
77
What does renal excretion depend on?
renal function renal bloodflow
78
How can renal excretion of overdosed aspirin be modified?
making urine more alkaline (bicarbonate intravenously) which encourages acid secretion into urine and removes aspirin from body
79
What can cause excretion problems and what should be done?
Renal Disease Chronic renal failure Drug doses must be reduced Liver disease Liver failure Drug doses must be reduced
80
What should you always do in situations of disease?
Always ask advice from the patient’s doctor about how much to reduce a drug use in an individual case will depend on liver/renal function Will depend on the drug being used
81
What is the plasma half-life and what does it vary by?
Time taken to eliminate half of the drug varies by mechanism of excretion
82
What is first order kinetics?
Drug metabolism increases as drug concentration increases i.e. large amount of drug will increase rate of excretion Excretion is by PASSIVE DIFFUSION only
83
What is zero order kinetics?
Drug metabolism is at a FIXED rate – ACTIVE process Irrespective of drug concentration Can lead to the drug accumulation if saturation exceeded
84
What is zero order kinetics fixed by?
by max capacity in enzyme systems of body
85
Why are zero order kinetics useful?
if drug level in current blood and time ago it was taken is known, it is possible to predict backwards to the max dose taken to assess whether or not it exceeded the hepatic metabolic levels (where above leads to free-radical formation) applies to paracetemol
86
What is the problem with frequency of dosing?
TOO FREQUENT will result in plasma levels that may be toxic TOO INFREQUENT will result in sub-therapeutic plasma levels and no clinical effect
87
What does drug toxcitiy depend on?
Depends upon the drug’s THERAPEUTIC INDEX
88
What route of absorption is least reliable?
oral
89
When should treatment be avoided in pregnency?
first trimester as crucial development happens during this period
90
Why are drugs used for sedation rarely used orally?
orally takes too long and may be unreliable
91
How do most drugs enter the brain?
transmembrane passive diffusion