Pharmacokinetics Flashcards

1
Q

How would potency be tested of a drug?

A

By plotting a log dose-response curve.

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2
Q

What would a partial agonist look like on a log dose-response curve?

A

Smaller curve with lower maximum.

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3
Q

Do cannabis and aspirin have local or systemic effects?

A

Systemic; pass through blood to the brain.

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4
Q

Give x2 examples of drugs which have local affects.

A

Salbutamol and betnovate (steroid cream).

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5
Q

Describe the difference in administration route between enteral and parenteral.

A
Enteral = oral; passes through GI.
Parenteral = inhalation, IM etc.
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6
Q

What type of drugs are filtered at the glomerulus?

A

Low molecular weight drugs.

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7
Q

What type of compound is acetylation in phase 2 metabolism associated with?

A

Aromatic amines

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8
Q

What is an example of a drug which uses methylation as its phase 2 metabolism?

A

Levodopa

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9
Q

Where are the cytochrome P450 enzymes found?

A

In the mitochondria

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10
Q

What type of reactions are the cytochrome P450 enzymes mainly involved with?

A

Oxidation.

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11
Q

What type of reactions are phase 1 reactions usually?

A

Oxidation or reduction.

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12
Q

What type of reactions are phase 2 reactions usually?

A

Conjugation.

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13
Q

Glutathione is a tripeptide consisting of which 3 amino acids?

A

Glutamine, cysteine and glycine.

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14
Q

What type of reaction makes Levodopa?

A

Methylation in phase 2 metabolism.

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15
Q

What is the reaction called from converting NO2 to NH2?

A

Nitro-reduction using nitro-reductase

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16
Q

If a large polar group is added in phase 2 metabolism, what type of reaction is this?

A

Glucuronidation.

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17
Q

What type of reaction is acetylation?

A

Phase 2

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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.

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19
Q

What is the official name for an exercise bike/ machine?

A

Ergometer

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20
Q

How do beta blockers help arrhythmias?

A

Slow conduction through the AVN.

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21
Q

What type of Beta receptors are found on the liver?

A

b2

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22
Q

Name an a1 selective drug

A

Prazosin

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23
Q

Name an b1 selective drug

A

Atenolol, Pindolol

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24
Q

Which is the main inhibitory adrenoceptor?

A

a2

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25
Q

What is the main effect of a1 adrenoceptor?

A

Vasoconstriction

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26
Q

What is the name of the non selective drug for a1, B1 and B2 adrenoceptors?

A

Carvedilol

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27
Q

What is mydriasis?

A

Dilatation of the pupil

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28
Q

Why may we want mydriasis to occur?

A

Prior to surgery; helps inspection of retina, prevents iris adhering to lens.

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29
Q

How can we induce mydriasis?

A

Give antimuscarinic agents: tropicamide

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30
Q

What is the term for constriction of the pupil?

A

Miosis

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31
Q

How we cause miosis?

A

Using muscarinic agents e.g. Pilocarpine.

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32
Q

What is cataract?

A

Opacity of the lens

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33
Q

What structure makes the aqueous humour?

A

The ciliary body

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34
Q

Describe the passage of aqueous humour

A

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.

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35
Q

Why does glaucoma occur?

A

Increased pressure within the eye damages optic nerve fibres resulting in optic atrophy.

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36
Q

What is primary glaucoma?

A

idiopathic

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37
Q

What is pilocarpine?

A

A cholinergic drug

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38
Q

What is the normal cholesterol range?

A

5.3-6.2 mmol/L

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39
Q

Why can beta blockers cause cold extremities?

A

Prevents peripheral vasodilatation; b2 receptors on vasculature. b2 receptors are dominant on peripheral tissues.

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40
Q

Why may a response to beta blockers decrease in the elderly?

A

Beta adrenergic receptors decrease with age.

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41
Q

What is Ritonavir?

A

A cytochrome P450 inhibitor

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42
Q

The more lipid soluble a drug is, will this increase or decrease the half life?

A

Increase the half life; drug sits in fat of the body.

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43
Q

Which form of drug antagonism describes the ability of adrenaline to reduce the effects of the mast cell derived histamine during an anaphylactic response?

A

Physiological antagonism.

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44
Q

How would a log-dose response curve of a full agonist compare with a partial agonist?

A

Partial agonist = to the right at lower maximum.

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45
Q

If blood levels of a drug are higher in the hepatic portal venous system than in major arteries, what is the method of administration?

A

Oral

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46
Q

Name the 3 Phase 1 reactions?

A

Reduction, oxidation and hydrolysis.

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47
Q

Define Mydriasis

A

Dilatation of the pupil

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48
Q

What affect do muscarinic receptors have on dopaminergic receptors?

A

Muscarinic receptors inhibit dopaminergic receptors.

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49
Q

Give x2 physiological aspects of an anaphylactic response.

A

Bronchospasm and hypotension.

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50
Q

How would a position change on a graph in the presence of a fixed dose antagonist?

A

Right below mark (but no shift to left or right).

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51
Q

How would losing weight and quitting smoking help in hypertension?

A

Losing weight = lowers cholesterol levels = reduces vascular disease risk.
Cigarettes = haven nicotine = a vasoconstrictor.

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52
Q

Through which mechanism does benzofluazide work?

A

Inhibits the Na+/Cl- transporter = less sodium is absorbed. It increases distal sodium concentration.

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53
Q

Which class of drug is ramipril?

A

ACE Inhibitor.

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54
Q

Why would you use Digoxin in Atrial Fibrillation?

A

Inhibits the Na+/K+ ATPase pump in the AVN = reduces rate of conduction through AVN. ALSO through stimulation of vagus nerve.

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55
Q

What is the mechanism through which simvastatin works?

A

HMG-CoA Reductase Inhibitor

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56
Q

What is the mechanism through which aspirin works?

A

COX-1 Inhibitor

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57
Q

Which is the rate limiting step in cholesterol synthesis?

A

HMG-CoA conversion to mevalonic acid.

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58
Q

Which class of drug is frusemide?

A

Loop diuretic - triple transporter inhibitor.

59
Q

Why are beta blockers given slowly to patients with heart failure?

A

Do not want to cause a hypotensive crisis.

60
Q

Where is ACh found in the autonomic system?

A

Parasympathetic and sympathetic pre-ganglionic fibres and post-ganglionic fibres.
Post-ganglionic fibre for sweat gland.
Sympathetic fibres innervating the adrenal medulla

61
Q

What type of receptors does ACh activate?

A

Muscarinic AND nicotinic

remember nicotinic at the nerve, muscarinic at the organ

62
Q

Define airway resistance

A

The amount of pressure required to deliver gaseous flow.

63
Q

What are some side effects of muscarinic antagonists?

A

Dry mouth, GI Disturbances,

64
Q

Apart from histamine, name two other compounds which cause bronchoconstriction.

A

Leucotrienes, bradykinins.

65
Q

Which is the brown inhaler?

A

Dexamethasone

66
Q

Which method of drug administration has the fastest affect on the brain?

A

Inhalation

67
Q

Which part of the hypothalamus has food seeking behaviour?

A

The lateral hypothalamus

Orexin + MCH.

68
Q

Which enzyme is used by the stomach to break down alcohol?

A

Alcohol dehydrogenase

69
Q

What is the prothrombinase complex?

A

Factors Va and Xa.

70
Q

What is the name for IIa?

A

Thrombin

71
Q

Which anticoagulant inhibits IIa?

A

Dabigatran

72
Q

Which anticoagulant inhibits Xa?

A

Rivaroxaban

73
Q

How does aspirin work?

A

COX-1 inhibitor = prevents TXA2

74
Q

How does Clopidogrel work?

A

ADP receptor antagonist

75
Q

What does antithrombin inhibit in terms of factor?

A

IIa and Xa - remember Xa too!!

76
Q

Where are white thrombi found in the artery?

A

In the endothelial wall (not the lumen)

77
Q

What is Alteplase?

A

A thrombolytic - causes plasminogen to convert to plasmin

78
Q

What is the role of plasmin?

A

To degrade fibrin strands

79
Q

What is tPA and give an example.

A

Tissue plasminogen activator = Alteplase.

80
Q

Which prostaglandin activates receptors EP1-EP4?

A

PGE2.

81
Q

Does aspirin reversibly or irreversibly inhibit COX-1?

A

Irreversibly.

82
Q

What is the symbol for prostacyclin?

A

PGI2.

83
Q

Is PGE2 a prostaglandin or prostacyclin?

A

Prostaglandin

84
Q

Where are aminosalicylates used?

A

In Ulcerative colitis - not Crohn’s disease ( do not work)

85
Q

Which is the treatment of preferred choice in ulcerative colitis?

A

Aminosalicylates; not glucocorticoids.

86
Q

Which is the treatment of preffered choice in Crohn’s disease?

A

Glucocorticoids

87
Q

Name a difference between the parasympathetic and sympathetic system in location.

A
Parasympathetic = discrete.
Sympathetic = widespread.
88
Q

What are the 3 types of receptors?

A

Muscarinic, nicotonic, adrenoceptors

89
Q

What is the idea of ‘use dependence’?

A

The more a drug is used, the greater its effect.

90
Q

What is Drug Tolerance?

A

A gradual decrease in responsiveness to a drug.

91
Q

What are the two uptake mechanisms for noradrenaline?

A
  1. Into neuronal tissue

2. Into extraneuronal tissue

92
Q

a1, a2, b1 and b2 are what type of receptors?

A

Adrenoceptors [Which are GPCRs].

93
Q

Which dominates in the sympathetic system - near or long sighted vision?

A

Long sighted vision.

94
Q

Which route is faster - inhalation or IV?

A

Inhalation

95
Q

Which system innervates the arterioles?

A

The sympathetic system

96
Q

Which system dominates at rest - sympathetic or parasympathetic?

A

Parasympathetic

97
Q

B2 has what affect on vasculature?

A

Vasodilatation on vasculature

98
Q

What is an example of chemical antagonism?

A

Dimercapol chelating agent in solution

99
Q

All drugs have affinity. True or false.

A

True.

100
Q

Name a commonly used anti-emetic.

A

Hyoscine

101
Q

Which system is in charge of sweat glands and through which neurotransmitters at pre/post ganglionic fibres?

A

Sympathetic system.

ACh at pre and post ganglionic fibre

102
Q

Give an example of an inotropic receptor

A

Nicotinic receptors

GABA

103
Q

Give an example of a GPCR

A

B1 in heart

104
Q

Give an example of Tyrosine linked receptors

A

Insulin receptors, Growth factor receptors

105
Q

Give an example of an intracellular receptor

A

Steroid receptors

106
Q

What are the two ion channel types?

A

Voltaged gated

Receptor linked

107
Q

Describe the MoA of most anticonvulsants?

A

Fast onset, long duration of action.

108
Q

What is the parasympathetic system’s affect on the heart?

A

Activates an inhibitory pathway.

109
Q

Name the 5 types of drug tolerance

A
Pharmacokinetic factors
Loss of receptors
Change in receptors
Exhaustion of stores
Physiological adaptation
110
Q

Give an example of a pharmacokinetic factor in drug tolerance.

A

Drinking more alcohol = become more tolerant.

111
Q

When may you have a loss of receptors in drug tolerance?

A

Over stimulation can lead to endocytosis of receptors.

112
Q

A change in receptors describes what in tolerance?

A

Change of shape of receptors, rather htan number (this is another reason for drug tolerance being loss of receptors).

113
Q

Give an example of exhaustion of stores in drug tolerance

A

Amphetamine.

114
Q

Define affinity.

A

Likeliness of drug to seek and bind a receptor

115
Q

Define efficacy.

A

A confirmational change to receptor to cause action.

116
Q

How does Digoxin work?

A

Inhibits Na+/K+ ATPase pump = increases calcium concentration.

117
Q

What are the two types of antagonist?

A

Competitive and irreversible. Not competitive and non-competitive.

118
Q

Name two irreversible drugs of action.

A

Aspirin and Lidocaine.

119
Q

What does a drug have to be to cross BBB

A

Non-polar (uncharged).

120
Q

How does Botulinum work?

A

Binds to SNARE complex. SNARE opens vesicles. Prevents ACh release into synapse.

121
Q

What type of vision is controlled by the parasympathetic and through which muscle?

A

Near by vision = contraction of ciliary muscle.

122
Q

What is Tubocurarine?

A

A competitive NMJ blocker

123
Q

What are the two types of NMJ blocking drugs?

A

Depolarising and non-depolarising.

124
Q

Give an example of x1 depolarising NMJ blocker and x1 non-depolarising NMJ blocker

A
Suxamethonium = depolarising.
Tubocurarine = non depolarising.
125
Q

What is the affect of muscarinic receptor antagonists on sweating?

A

Reduced sweating

126
Q

How can we treat anticholinesterase poisoning?

A

Atropine

Artificial respiration

127
Q

What is the affect of mepyramine on a log-dose curve of muscarinic receptor responses?

A

Superimposes; acts on different receptors (histamine receptors).

128
Q

Are stomach cramps caused by parasympathetic or sympathetic action?

A

Parasympathetic; increased motility.

129
Q

Why is a charged drug better than an uncharged if inhaled?

A

Will not cross BBB. Do not want it to cross many lipid membranes to cause systemic side effects.

130
Q

Which is the fastest administration speed?

A

Inhalation

131
Q

How is Aspirin absorbed in the stomach compared with the small intestine?

A

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
Q

If a molecule is ionised can it cross a lipid membrane?

A

No; must be uncharged.

133
Q

Name two non-specific drugs.

A

General anaesthetics and antacids.

134
Q

Define surmountable

A

Drug can be added and added to overcome receptor/ target site. Competitive inhibitors are surmountable.

135
Q

Is atropine competitive or non-competitive?

A

Competitive

136
Q

Is propranolol competitive or non-competitive?

A

Competitive

137
Q

What can we give to patients to encourage excretion of a drug?

A

Sodium bicarbonate; increases pH = more ionised environment = drug is not as well reabsorbed.

138
Q

In what kind of environment is a drug excreted?

A

Alkaline environment; drug is ionised = does not pass back into membranes.

139
Q

Where are M1, M2 and M3 receptors found respectively?

A

M1 = neuronal, M2 = cardiac, M3 = exocrine glands (GI tract)

140
Q

Vasculature is controlled by which system?

A

The sympathetic system.

141
Q

Which is reversible between competitive and non-competitive inhibitors?

A

Competitive inhibitors are reversible.

142
Q

What will be the affect of a non competitive inhibitor on a log-dose curve?

A

Shift moves to right and lower max.

143
Q

Alkaline environments have what affect on a drug?

A

Ionise the drug.