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Pharmacology Test #3 > Vasodilators > Flashcards

Vasodilators Flashcards

1
Q

Cyclic GMP modulators

A

organic nitrates/nitrites
PDE inhibitors
vasoactive peptides

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2
Q

Vasodilators

A

Cyclic GMP modulators

K+ channel agonists

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3
Q

Isoforms of nitric oxide synthase

A

nNOS, iNOS, eNOS

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4
Q

What aa is NO generated from

A

arginine

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5
Q

Where is NOS?

A

in the vascular endothelium

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6
Q

Where does NO diffuse to?

A

diffuses to the vascular smooth muscle

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7
Q

Where is eNOS found

A

in the endothelial cells of the vasculature

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8
Q

Guanylate cyclase is found

A

in the vascular smooth muscle

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9
Q

Exogenously applied NO can directly do what?

A

relax smooth muscle

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10
Q

Prostacyclin inhibits

A

platelet aggregation

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11
Q

What does aceylcholine do?

A

relaxes smooth muscle: increases Ca2+ which activates NOS

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12
Q

NO binds to

A

heme iron prosthetic group in guanylate cyclase

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13
Q

NO binding stimulates what?

A

production of cGMP and activating protein kinase G

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14
Q

How does protein kinase G relax smooth muscle?

A

inhibition of L-type Ca2+ channels
stimulation of Ca2+ activated K+ channels
decreased MLC phophorylation
Enhanced Ca2+ uptake into the ER

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15
Q

Organic nitrates are

A

non-selective vasodilators

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16
Q

Organic nitrates breakdown to

A

nitric oxide (by aldehyde dehydrogenase)

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17
Q

Organic nitrates don’t require

A

functional endothelium

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18
Q

Orgnaic nitrates can be administered how?

A

acute or chronic administration

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19
Q

Three most important nitrates/nitrites used extensively in the US

A

Glyceryl trinitrate (GTN)
Isosorbide dinitrate
Isosorbide mononitrate

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20
Q

Why is amylnitrite not used much?

A

drug of abuse

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21
Q

Organic nitrate used in Europe

A

Pentaerythritol Tetranitrate (PETN)

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22
Q

Active ingredient in SEMTX/C4 (explosive)

A

Pentaerythritol Tetranitrate

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23
Q

Why do some populations not respond as well to Glycerol Trinitrate?

A

Glu504 Lys polymorphism in ALDH-2
Glu504 is 10X more efficient in metabolizing GTN
30-50% of Asian population has at least one Lys504 allele

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24
Q

Likely accounts for the lack of efficacy of GTN in a large percentage of the Asian population

A

30-50% of the asian population has at least one Lys504 allele

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25
Q

Lys504 allele also accounts for

A

alcohol intolerance in asian populations

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26
Q

Prostacyclin analogs (vasodilators)

A

PGI2 (epoprostenol) - IV
Treprostinil (Remodulin) - Oral, IV
Iloprost (Ventavis) - Inhalation

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27
Q

Prostacyclin analogs used to treat

A

pulmonary arterial hypertension

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28
Q

Hydralazine

A

dilates arterioles preferentially; appears to interfere with release of Ca2+ from the ER; can induce a lupus-like syndrome

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29
Q

BiDil

A

Isosorbidide (ISDN) + Hydralazine

antioxidant activity potentiates vasodilatory activity of ISDN

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30
Q

Who does BiDil decrease mortality in?

A

in African Americans with CHF

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31
Q

Sodium Nitroprusside given

A

given IV for acute management of severe hypertensive crisis and severe decompensated heart failure

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32
Q

What does sodium nitroprusside do?

A

dilates veins and arterioles

33
Q

How is sodium nitroprusside metabolized?

A

metabolized in erythrocytes in No, 4CN-, and cyanmethemoglobin (limits duration of treatment)

34
Q

CN- can inhibit

A

oxidative metabolism - lactic acid accumulation

35
Q

CN- converted to

A

less toxic SCN- by rhodanase, excreted via kidney

36
Q

Sodium thiosulfate or hydroxocobalamin may be used for

A

detoxification

37
Q

Riociguate (Adempas) is an

A

allosteric activator of sGC

38
Q

Riociguate (Adempas) is used for

A

pulmonary hypertention

39
Q

What does riociguate do?

A

potentiates the effect of NO
stimulates sGC activity allosterically
increases cGMP concentration in vascular SM

40
Q

Contraindications for riociguate

A

not combined with nitrates or PDE5 inhibitors
contraindicated in pregnancy
risk of hemorrhage

41
Q

Riociguate is a substrate for

A

P-gp, CYP1A1, CYP3A

42
Q

Alternative mechanism of action for NO

A

covalent modification of proteins by nitrosyl transfer from glutathione

43
Q

Phosphodiesterase (PDE3) inhibitors

A

(In)Amrinone

Milrinone

44
Q

Phosphodiesterase (PDE5) inhibitors

A

Dipyridamole

Sildenafil

45
Q

Amrinone/Milrinone

A

given intravenously
direct positive inotropic effect on myocardium
minimal chronotropic effect
direct vasodilatory effect on vascular SM

46
Q

Amrinone/Milrinone used mainly in

A

CHF (acute treatment)

47
Q

Sildenafil is a potent and specific inhibitor of

A

cGMP PDE5

48
Q

Sildenafil has 10 fold selectivity over

A

inhibition of PDE6 (retina)

49
Q

What can sildenafil cause

A

blueish vision

50
Q

Sildenafil has 400 fold selectivity over

A

inhibition of PDE3 (CV)

51
Q

Sildenafil has a lack of

A

systemic vasodilation

52
Q

PDE5 is predominant in the

A

corpus cavernosum

53
Q

PDE6 is in the

A

retina

54
Q

Selective PDE5 inhibitors

A

Tadalafil (Cialis)
Vardenafil (Lefitra)
Sildenafil (Viagra)

55
Q

Levitra compared to Viagra

A

shorter time to onset than Viagra

more selective for PDE5 than Viagra

56
Q

Cialis compared to Viagra

A

more selective for PDE5 than Viagra

longer duration of action than Viagra or Levitra

57
Q

Where is human type B natriuretic peptide synthesized?

A

synthesized and secreted from heart muscle in response to increased blood volume

58
Q

Natrecor (nesiritide) is given and used in?

A

given IV in acutely decompensated heart failure

59
Q

Natrecor (nesiritide) does what?

A

binds to and activates membrane-bound guanylate cyclase in vascular smooth muscle and endothelial cells

60
Q

Vasoconstrictors

A

angiotensin, alpha1-agonists, endothelin

61
Q

Vasodilators

A

beta2-agonists, CGRP, VIP

62
Q

What does increasing K+ channel opening do to vascular SM?

A

relaxes vascular smooth muscle

63
Q

Which ion sets the membrane potential?

A

K+ flux sets the membrane potential

64
Q

What happens the longer K+ channels are open?

A

the closer the membrane potential is to the K+ equilibrium potential

65
Q

What happens the closer the membrane potential is to the K+ equilibrium potential?

A

the harder it is to depolarize the membrane enough to open Voltage-gated Ca2+ channels

66
Q

K+ channel agonists/openers

A

Minoxidil

Diazoxide

67
Q

Minoxidil activated by

A

activated in vivo by sulfotransferase

68
Q

Minoxidil used with

A

loop diuretics and beta blockers

69
Q

Minoxidil is a

A

very potent vasodilator - effective in severe, drug resistant forms of hypertension

70
Q

What contributes to Minoxidil’s efficacy?

A

cAMP PDE inhibition

71
Q

How is Minoxidil given?

A

given orally (or topically to promote hair growth)

72
Q

How is Diazoxide used?

A

intravenously to treat acute hypertension

orally for hypoglycemia secondary to hyprinsulinemia

73
Q

Diazoxide is a

A

very potent vasodilator - effective in severe drug resistant forms of hypertension

74
Q

Diazoxide inhibits

A

release of insulin from pancreatic beta cells

75
Q

Adenosine binds to

A

alpha1 receptor-a GPCR

76
Q

What does adenosine do

A

increases conductance of a K+ channel - hyperpolarization and relaxation

77
Q

How is adenosine given?

A

given IV - during coronary stress tests

78
Q

Describe the vasodilation mechanism of adenosine.

A

Gbetay on the A1 (adenosine) receptors binds and activates GIRK; conducts K+ efflux and membrane hyperpolarization

79
Q

GIRK stands for

A

G-protein activated inwardly rectifying K+ channel

Pharmacology Test #3 (13 decks)

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