PHARMACOLOGY Flashcards

1
Q

What drug class is cocaine?

A

a noradrenaline reuptake inhibitor/ sodium channel blocker

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2
Q

what is cocaine used for?

A

a local anesthetic. It is applied to certain areas of the body (for example, the nose, mouth, or throat) to cause loss of feeling or numbness.

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3
Q

what is cocaines mechanism of action?

A

Cocaine produces anaesthesia by inhibiting excitation of nerve endings. This is achieved by reversibly binding to and inactivating sodium channels, which are necessary for the depolarization of nerve cell membranes and subsequent propagation of impulses along the course of the nerve.

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4
Q

what causes cocaine to be addictive?

A

the increase in dopamine levels it causes by preventing re-uptake of dopamine into pre-synaptic neurones

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5
Q

why does cocaine cause vasoconstriction?

A

This is a result of its blockade of norepinephrine reuptake in the autonomic nervous system

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6
Q

what drug class is dexamphetamine?

A

Noradrenaline releaser

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7
Q

what are amphetamines?

A

CNS stimultants

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8
Q

what are dexamphetamine’s effects?

A

elevations of systolic and diastolic blood pressures and weak bronchodilator and respiratory stimulant action

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9
Q

what are dexamphetamines proposed mechanisms of action?

A

1) Stimulation of the release of norepinephrine from central adrenergic receptors.
2) At higher dosages, it causes dopamine release from the mesocorticolimbic system and the nigrostriatal systems by reversal of the monoamine transporters.
3) Act as a direct agonist on central 5-HT receptors
4) Inhibit monoamine oxidase (MAO).
5) In the periphery cause the release of noradrenaline by acting on the adrenergic nerve terminals and alpha- and beta-receptors.

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10
Q

what drug class is dopamine?

A

Dopamine receptor agonist

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11
Q

what does dopamine act as an agonist for in the brain?

A

D1, D2, D3, D4, D5

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12
Q

how does dopamine cause an increased heart rate and cardiac contractility?

A

Dopamine acts on beta-adrenoceptors indirectly by causing release of norepinephrine from storage sites in sympathetic nerve endings producing positive chronotropic and inotropic effects on the myocardium

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13
Q

what drug class is hemicholinium?

A

choline re-uptake inhibitor.

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14
Q

what drug class us fluoxetine?

A

a selective serotonin reuptake inhibitor

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15
Q

what is fluoxetine used to treat?

A

depression, bulimia nervosa, premenstrual dysphoric disorder, panic disorder and post-traumatic stress

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16
Q

what is fluoxetine’s mechanism of action?

A

Fluoxetine is metabolized to norfluoxetine. Its mechanism of action is the inhibition of the serotonin reuptake pump of the neuronal membrane, enhancing the actions of serotonin on 5HT1A autoreceptors.

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17
Q

what drug class is imipramine?

A

a catecholamine uptake inhibitor

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18
Q

what is imipramine’s mechanism of action?

A

inhibiting the sodium-dependent serotonin transporter and sodium-dependent norepinephrine transporter preventing or reducing the reuptake of norepinephrine and serotonin by nerve cells. The slowing of the uptake of these neurotransmitters is thought to contribute to relieving symptoms of depression.

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19
Q

how can imipramine cause enhanced serotonergic transmission with chronic use?

A

causes down-regulation of cerebral cortical b-adrenergic receptors and sensitization of post-synaptic serotonergic receptors

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20
Q

how long does it take to see antidepressant effects of imipramine?

A

2-4 weeks, can be up to 8 weeks

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21
Q

what drug class is levodopa?

A

dopamine replacement therapy

22
Q

what is levodopa a natural form of?

A

dihydroxyphenylalanine

23
Q

what is levodopa a precursor of?

A

dopamine

24
Q

what must be taken alongside levodopa?

A

a dopamine decarboxylase to reduce metabolism at the gut wall

25
Q

can levodopa cross the blood-brain barrier?

A

yes

26
Q

describe levodopas mechanism?

A

it crosses the blood-brain barrier and then can be taken up by dopaminergic neurones and converted to dopamine.

27
Q

what is levodopa used for?

A

replacing dopamine that is lost in Parkinson’s disease

28
Q

what drug class is nicotine?

A

a nicotinic acetylcholine agonist

29
Q

what are used to treat smoking withdrawal syndrome?

A

nicotine inhalers and patches

30
Q

describe the mechanism of nicotine that causes the euphoric and addictive properties of nicotine?

A

In the brain, nicotine binds to nicotinic acetylcholine receptors on dopaminergic neurons in the cortico-limbic pathways causing depolarization and activating voltage-gated calcium channels and the release of dopamine into the synapse.

31
Q

what is nicotine an agonist for?

A

nicotinic acetylcholine receptors on autonomic ganglia, the adrenal medulla, neuromuscular junctions and in the brain.

32
Q

describe the mechanism of nicotine that causes vasoconstriction, increased blood pressure, increased heart rate and increased blood sugar?

A

it binds to nicotinic acetylcholine receptors on the chromaffin cells in the adrenal medulla. This binding opens the ion channel allowing influx of sodium, causing depolarization, activation of the voltage-gated calcium channels, triggering epinephrine release from intracellular vesicles into the bloodstream

33
Q

what drug class is phenelzine?

A

a monoamine oxidase inhibitor/ antidepressant

34
Q

what is phenelzine’s mechanism of action?

A

irreversibly inhibits monoamine oxidase and therefore increases the concentration of free amines, most specifically serotonin and norepinephrine

35
Q

what are the 2 types of monoamine oxisases?

A

MAO-A

MAO-B

36
Q

where is MAO-A found?

A

in cells in the periphery

37
Q

where is MAO-B found?

A

extracellularly and in the brain

38
Q

what does MAO-A do?

A

catalyses the breakdown of serotonin, norepinephrine, epinephrine, dopamine and tyramine

39
Q

what does MAO-B do?

A

catalyses phenylethylamine, norepinephrine, epinephrine, dopamine and tyramine

40
Q

do MAO-A and MAO-B both have antidepressant features?

A

no, only MAO-A

41
Q

what drug class is pralidoxime?

A

cholinesterase reactivator

42
Q

what is pralidoxime used for?

A

as an antidote to organophosphate pesticides and chemicals

43
Q

what is pralidoximes mechanism?

A

If given in 24 hours after organophosphate exposure, pralidoxime cleaves the phosphate-ester bond formed between the organophosphate and acetylcholinesterase, reactivating the acetylcholinesterase, allowing the breakdown of accumulated acetylcholine, and reestablishing the normal function of neuromuscular junctions.

44
Q

what are organophosphates effect on acetylcholinesterase?

A

Organophosphates bind to the esteratic site of acetylcholinesterase, resulting in its reversible inactivation. Acetylcholinesterase inhibition causes acetylcholine accumulation in synapses, producing continuous stimulation of cholinergic fibers throughout the CNS.

45
Q

why is atropine require alongside pralidoxime?

A

Because pralidoxime is less effective in relieving depression of the respiratory center so it can block the effect of accumulated acetylcholine at this site.

46
Q

what drug class is sarin?

A

an irreversible cholinesterase inhibitor

47
Q

what is the mechanism of nerve agents?

A

Nerve agents inhibit cholinesterases. Therefore this causes the acetylcholine concentration to increase causing potentiation of the effect of acetylcholine at cholinergic synapses.

48
Q

what are cholinesterase inhibitors used for?

A

potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system

49
Q

what drug class is tropicamide?

A

a muscarinic cholinergic receptor antagonist

50
Q

what is tropic amide used to treat?

A

mydriasis and cycloplegia

51
Q

what is tropic amides mechanism of action?

A

it inhibits the muscarinic receptor M4. this inhibition leads to pupil dilation and relaxation of the lens.