Pharmacokinetics Flashcards
1
Q
How would potency be tested of a drug?
A
By plotting a log dose-response curve.
2
Q
What would a partial agonist look like on a log dose-response curve?
A
Smaller curve with lower maximum.
3
Q
Do cannabis and aspirin have local or systemic effects?
A
Systemic; pass through blood to the brain.
4
Q
Give x2 examples of drugs which have local affects.
A
Salbutamol and betnovate (steroid cream).
5
Q
Describe the difference in administration route between enteral and parenteral.
A
Enteral = oral; passes through GI. Parenteral = inhalation, IM etc.
6
Q
What type of drugs are filtered at the glomerulus?
A
Low molecular weight drugs.
7
Q
What type of compound is acetylation in phase 2 metabolism associated with?
A
Aromatic amines
8
Q
What is an example of a drug which uses methylation as its phase 2 metabolism?
A
Levodopa
9
Q
Where are the cytochrome P450 enzymes found?
A
In the mitochondria
10
Q
What type of reactions are the cytochrome P450 enzymes mainly involved with?
A
Oxidation.
11
Q
What type of reactions are phase 1 reactions usually?
A
Oxidation or reduction.
12
Q
What type of reactions are phase 2 reactions usually?
A
Conjugation.
13
Q
Glutathione is a tripeptide consisting of which 3 amino acids?
A
Glutamine, cysteine and glycine.
14
Q
What type of reaction makes Levodopa?
A
Methylation in phase 2 metabolism.
15
Q
What is the reaction called from converting NO2 to NH2?
A
Nitro-reduction using nitro-reductase
16
Q
If a large polar group is added in phase 2 metabolism, what type of reaction is this?
A
Glucuronidation.
17
Q
What type of reaction is acetylation?
A
Phase 2
18
Q
Which are the two groups of patients who should not be treated with B-adrenoceptor antagonists?
A
Diabetics; b2 receptor on liver (will increase glucose output)
Asthma: b2 receptor. When activated = bronchoconstriction.
19
Q
What is the official name for an exercise bike/ machine?
A
Ergometer
20
Q
How do beta blockers help arrhythmias?
A
Slow conduction through the AVN.
21
Q
What type of Beta receptors are found on the liver?
A
b2
22
Q
Name an a1 selective drug
A
Prazosin
23
Q
Name an b1 selective drug
A
Atenolol, Pindolol
24
Q
Which is the main inhibitory adrenoceptor?
A
a2
25
What is the main effect of a1 adrenoceptor?
Vasoconstriction
26
What is the name of the non selective drug for a1, B1 and B2 adrenoceptors?
Carvedilol
27
What is mydriasis?
Dilatation of the pupil
28
Why may we want mydriasis to occur?
Prior to surgery; helps inspection of retina, prevents iris adhering to lens.
29
How can we induce mydriasis?
Give antimuscarinic agents: tropicamide
30
What is the term for constriction of the pupil?
Miosis
31
How we cause miosis?
Using muscarinic agents e.g. Pilocarpine.
32
What is cataract?
Opacity of the lens
33
What structure makes the aqueous humour?
The ciliary body
34
Describe the passage of aqueous humour
Aqueous humour passes through the narrow space between the iris and the lens into the anterior chamber. From there it returns to the venous circulation through the pores of the corneo-scleral trabeculum in the anterior chamber wall and through the Canal of Schlemm. The hyperosmolality in the cleft causes water flow from the stroma to produce continuous aqueous humour.
35
Why does glaucoma occur?
Increased pressure within the eye damages optic nerve fibres resulting in optic atrophy.
36
What is primary glaucoma?
idiopathic
37
What is pilocarpine?
A cholinergic drug
38
What is the normal cholesterol range?
5.3-6.2 mmol/L
39
Why can beta blockers cause cold extremities?
Prevents peripheral vasodilatation; b2 receptors on vasculature. b2 receptors are dominant on peripheral tissues.
40
Why may a response to beta blockers decrease in the elderly?
Beta adrenergic receptors decrease with age.
41
What is Ritonavir?
A cytochrome P450 inhibitor
42
The more lipid soluble a drug is, will this increase or decrease the half life?
Increase the half life; drug sits in fat of the body.
43
Which form of drug antagonism describes the ability of adrenaline to reduce the effects of the mast cell derived histamine during an anaphylactic response?
Physiological antagonism.
44
How would a log-dose response curve of a full agonist compare with a partial agonist?
Partial agonist = to the right at lower maximum.
45
If blood levels of a drug are higher in the hepatic portal venous system than in major arteries, what is the method of administration?
Oral
46
Name the 3 Phase 1 reactions?
Reduction, oxidation and hydrolysis.
47
Define Mydriasis
Dilatation of the pupil
48
What affect do muscarinic receptors have on dopaminergic receptors?
Muscarinic receptors inhibit dopaminergic receptors.
49
Give x2 physiological aspects of an anaphylactic response.
Bronchospasm and hypotension.
50
How would a position change on a graph in the presence of a fixed dose antagonist?
Right below mark (but no shift to left or right).
51
How would losing weight and quitting smoking help in hypertension?
Losing weight = lowers cholesterol levels = reduces vascular disease risk.
Cigarettes = haven nicotine = a vasoconstrictor.
52
Through which mechanism does benzofluazide work?
Inhibits the Na+/Cl- transporter = less sodium is absorbed. It increases distal sodium concentration.
53
Which class of drug is ramipril?
ACE Inhibitor.
54
Why would you use Digoxin in Atrial Fibrillation?
Inhibits the Na+/K+ ATPase pump in the AVN = reduces rate of conduction through AVN. ALSO through stimulation of vagus nerve.
55
What is the mechanism through which simvastatin works?
HMG-CoA Reductase Inhibitor
56
What is the mechanism through which aspirin works?
COX-1 Inhibitor
57
Which is the rate limiting step in cholesterol synthesis?
HMG-CoA conversion to mevalonic acid.
58
Which class of drug is frusemide?
Loop diuretic - triple transporter inhibitor.
59
Why are beta blockers given slowly to patients with heart failure?
Do not want to cause a hypotensive crisis.
60
Where is ACh found in the autonomic system?
Parasympathetic and sympathetic pre-ganglionic fibres and post-ganglionic fibres.
Post-ganglionic fibre for sweat gland.
Sympathetic fibres innervating the adrenal medulla
61
What type of receptors does ACh activate?
Muscarinic AND nicotinic
| remember nicotinic at the nerve, muscarinic at the organ
62
Define airway resistance
The amount of pressure required to deliver gaseous flow.
63
What are some side effects of muscarinic antagonists?
Dry mouth, GI Disturbances,
64
Apart from histamine, name two other compounds which cause bronchoconstriction.
Leucotrienes, bradykinins.
65
Which is the brown inhaler?
Dexamethasone
66
Which method of drug administration has the fastest affect on the brain?
Inhalation
67
Which part of the hypothalamus has food seeking behaviour?
The lateral hypothalamus
| Orexin + MCH.
68
Which enzyme is used by the stomach to break down alcohol?
Alcohol dehydrogenase
69
What is the prothrombinase complex?
Factors Va and Xa.
70
What is the name for IIa?
Thrombin
71
Which anticoagulant inhibits IIa?
Dabigatran
72
Which anticoagulant inhibits Xa?
Rivaroxaban
73
How does aspirin work?
COX-1 inhibitor = prevents TXA2
74
How does Clopidogrel work?
ADP receptor antagonist
75
What does antithrombin inhibit in terms of factor?
IIa and Xa - remember Xa too!!
76
Where are white thrombi found in the artery?
In the endothelial wall (not the lumen)
77
What is Alteplase?
A thrombolytic - causes plasminogen to convert to plasmin
78
What is the role of plasmin?
To degrade fibrin strands
79
What is tPA and give an example.
Tissue plasminogen activator = Alteplase.
80
Which prostaglandin activates receptors EP1-EP4?
PGE2.
81
Does aspirin reversibly or irreversibly inhibit COX-1?
Irreversibly.
82
What is the symbol for prostacyclin?
PGI2.
83
Is PGE2 a prostaglandin or prostacyclin?
Prostaglandin
84
Where are aminosalicylates used?
In Ulcerative colitis - not Crohn's disease ( do not work)
85
Which is the treatment of preferred choice in ulcerative colitis?
Aminosalicylates; not glucocorticoids.
86
Which is the treatment of preffered choice in Crohn's disease?
Glucocorticoids
87
Name a difference between the parasympathetic and sympathetic system in location.
```
Parasympathetic = discrete.
Sympathetic = widespread.
```
88
What are the 3 types of receptors?
Muscarinic, nicotonic, adrenoceptors
89
What is the idea of 'use dependence'?
The more a drug is used, the greater its effect.
90
What is Drug Tolerance?
A gradual decrease in responsiveness to a drug.
91
What are the two uptake mechanisms for noradrenaline?
1. Into neuronal tissue
| 2. Into extraneuronal tissue
92
a1, a2, b1 and b2 are what type of receptors?
Adrenoceptors [Which are GPCRs].
93
Which dominates in the sympathetic system - near or long sighted vision?
Long sighted vision.
94
Which route is faster - inhalation or IV?
Inhalation
95
Which system innervates the arterioles?
The sympathetic system
96
Which system dominates at rest - sympathetic or parasympathetic?
Parasympathetic
97
B2 has what affect on vasculature?
Vasodilatation on vasculature
98
What is an example of chemical antagonism?
Dimercapol chelating agent in solution
99
All drugs have affinity. True or false.
True.
100
Name a commonly used anti-emetic.
Hyoscine
101
Which system is in charge of sweat glands and through which neurotransmitters at pre/post ganglionic fibres?
Sympathetic system.
| ACh at pre and post ganglionic fibre
102
Give an example of an inotropic receptor
Nicotinic receptors
| GABA
103
Give an example of a GPCR
B1 in heart
104
Give an example of Tyrosine linked receptors
Insulin receptors, Growth factor receptors
105
Give an example of an intracellular receptor
Steroid receptors
106
What are the two ion channel types?
Voltaged gated
| Receptor linked
107
Describe the MoA of most anticonvulsants?
Fast onset, long duration of action.
108
What is the parasympathetic system's affect on the heart?
Activates an inhibitory pathway.
109
Name the 5 types of drug tolerance
```
Pharmacokinetic factors
Loss of receptors
Change in receptors
Exhaustion of stores
Physiological adaptation
```
110
Give an example of a pharmacokinetic factor in drug tolerance.
Drinking more alcohol = become more tolerant.
111
When may you have a loss of receptors in drug tolerance?
Over stimulation can lead to endocytosis of receptors.
112
A change in receptors describes what in tolerance?
Change of shape of receptors, rather htan number (this is another reason for drug tolerance being loss of receptors).
113
Give an example of exhaustion of stores in drug tolerance
Amphetamine.
114
Define affinity.
Likeliness of drug to seek and bind a receptor
115
Define efficacy.
A confirmational change to receptor to cause action.
116
How does Digoxin work?
Inhibits Na+/K+ ATPase pump = increases calcium concentration.
117
What are the two types of antagonist?
Competitive and irreversible. Not competitive and non-competitive.
118
Name two irreversible drugs of action.
Aspirin and Lidocaine.
119
What does a drug have to be to cross BBB
Non-polar (uncharged).
120
How does Botulinum work?
Binds to SNARE complex. SNARE opens vesicles. Prevents ACh release into synapse.
121
What type of vision is controlled by the parasympathetic and through which muscle?
Near by vision = contraction of ciliary muscle.
122
What is Tubocurarine?
A competitive NMJ blocker
123
What are the two types of NMJ blocking drugs?
Depolarising and non-depolarising.
124
Give an example of x1 depolarising NMJ blocker and x1 non-depolarising NMJ blocker
```
Suxamethonium = depolarising.
Tubocurarine = non depolarising.
```
125
What is the affect of muscarinic receptor antagonists on sweating?
Reduced sweating
126
How can we treat anticholinesterase poisoning?
Atropine
| Artificial respiration
127
What is the affect of mepyramine on a log-dose curve of muscarinic receptor responses?
Superimposes; acts on different receptors (histamine receptors).
128
Are stomach cramps caused by parasympathetic or sympathetic action?
Parasympathetic; increased motility.
129
Why is a charged drug better than an uncharged if inhaled?
Will not cross BBB. Do not want it to cross many lipid membranes to cause systemic side effects.
130
Which is the fastest administration speed?
Inhalation
131
How is Aspirin absorbed in the stomach compared with the small intestine?
Aspirin is less acidic than stomach so aspirin moves into stomach and will be non-ionised.
In small intestine, aspirin is more acidic than alkaline SI environment so aspirin becomes ionised. Once ionised = cannot cross lipid membranes = ion trapping.
132
If a molecule is ionised can it cross a lipid membrane?
No; must be uncharged.
133
Name two non-specific drugs.
General anaesthetics and antacids.
134
Define surmountable
Drug can be added and added to overcome receptor/ target site. Competitive inhibitors are surmountable.
135
Is atropine competitive or non-competitive?
Competitive
136
Is propranolol competitive or non-competitive?
Competitive
137
What can we give to patients to encourage excretion of a drug?
Sodium bicarbonate; increases pH = more ionised environment = drug is not as well reabsorbed.
138
In what kind of environment is a drug excreted?
Alkaline environment; drug is ionised = does not pass back into membranes.
139
Where are M1, M2 and M3 receptors found respectively?
M1 = neuronal, M2 = cardiac, M3 = exocrine glands (GI tract)
140
Vasculature is controlled by which system?
The sympathetic system.
141
Which is reversible between competitive and non-competitive inhibitors?
Competitive inhibitors are reversible.
142
What will be the affect of a non competitive inhibitor on a log-dose curve?
Shift moves to right and lower max.
143
Alkaline environments have what affect on a drug?
Ionise the drug.
