Chapter 46: vasodilators Flashcards

1
Q

Agents that act primarily on the arterioles are called what?

A

Resistance vessels

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2
Q

Agents that act primarily on veins are what?

A

Capacitance vessels

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3
Q

What determines its hemodynamic effects and is a major determinant factor r/t both therapeutic and undesired effects?

A

Selectivity

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4
Q

What effect do arterioles have on afterload & cardiac workload

A

decrease in cardiac afterload & cardiac workload

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5
Q

What effects do arterioles have on cardiac output and tissue perfusion?

A

Increase in CO & tissue perfusion

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6
Q

What are some primary therapeutic uses of vasodialtors?

A

-Systemic & pulmonary HTN
-hypertensive crisis/pheochromocytoma
-angina pectoris/MI
-HF
-Peripheral vascular disease

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7
Q

What are 3 ADRs r/t vasodilation

A

-postural hypotension
-reflex tachycardia
-expansion of blood volume (w/ prolonged use)

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8
Q

Why would someone get postural hypotension r/t vasodilation

A

-relaxation of smooth muscle in the veins. gravity causes blood to pool. further decreases venous return. Decrease in CO & BP. Decreased ventricular pressure

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9
Q

Why would someone develop reflex tachycardia r/t vasodilation?

A
  • direct reduction in arterial pressure.
    -reduces CO.
  • can be due to arterial or venous dilation
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10
Q

What can you pretreat reflect tachycardia with?

A

Cardioselective beta blocker

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11
Q

What should pt use vasodilators with to prevent therapeutic effects from being cancelled out?

A

diuretics

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12
Q

What drug is a selective dilation of arterioles?

A

Hydralazine

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13
Q

if a person is takin hydralazine what would you notice about their arterial BP & peripheral resistance?

A

It falls

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14
Q

On hydralazine, a pts HR and contractility would do what?

A

Increase

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15
Q

What drug would you want to take with hydralazine to help with the cardiac effects?

A

Cardioselective beta-blocker (metoprolol)

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16
Q

hydralazine is inactivated by a metabolic process known as what?

A

Acetylation (rate is genetically determined)

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17
Q

What are 3 ADRs for hydralazine?

A
  • reflex tachycardia
    -increased blood volume
    -systemic lupus erythematosus-like syndrome
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18
Q

What 2 drugs can hydralazine be combined with?

A

-diuretics
-beta-blockers

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19
Q

A pt comes in and is complaining of fever, muscle and joint pain, and has nephritis, pericarditis, and positive rheumatoid antibodies. What syndrome do they have and what should you do if they are taking hydralazine?

A

Systemic lupus erythematosus-like syndrome
Discontinue drug

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20
Q

if a pt is a slow acetylator, what should you do to the dose?

A

Lower the dose
(they may not be inactivating the drug, so it may become toxic)

21
Q

If a pt is a rapid acetylator, what should you do to the dosage?

A

Increase dose
(They may need more of the drug d/t a fast metabolization of the drug)

22
Q

Which vasodilator produces significantly more selective dilation of the arterioles than hydralazine?

A

minoxidil

23
Q

Why would you give minoxidil?

A

For Pt with sever HTN & have not responded effectively w/ safer drugs

24
Q

What must minoxidil be metabolized to?

A

Minoxidil sulfate

25
Q

Minoxidil sulfate causes potassium channels to open resulting in what?

A

Efflux of potassium ions out of the cell

26
Q

Reducing their ability to contract is caused by what?

A

Hyperpolarization of the VSM

27
Q

What are 4 ADRs of minoxidil

A

-reflex tachycardia
-sodium and water retention
-hypertrichosis
-Pericardial effusion

28
Q

What is the main reason many pt stop taking minoxidil?

A

Hypertrichosis

29
Q

What adverse effect from minoxidil can lead to cardiac tamponade?

A

Pericardial effusion

30
Q

What diuretic can you not take with minoxidil and why?

A

potassium sparing because of hyperkalemia

31
Q

If loop diuretics is ineffective with the ADR of sodium and water retention from minoxidil what should you do?

A

Start dialysis or discontinue drug

32
Q

What is hypertrichosis and how many people develop it >4 weeks within taking minoxidil?

A

-excessive growth of hair
-specific pattern beginning on face then arms,legs,back
-80% of people develop
-caused by proliferation of epithelial cells at hair follicle base

33
Q

What is the drug of choice for hypertension emergencies?

A

Sodium Nitroprusside

34
Q

How is sodium nitroprusside administered?

A

IV infusion only

35
Q

Does sodium nitroprusside have a short or long duration of action?

A

Short

36
Q

What is given with sodium nitroprusside concurrently?

A

Oral antihypertensives

37
Q

Does sodium nitroprusside cause dilation on venous, arteriole, or both

A

both

38
Q

What is the most potent and fast-acting vasodilator available?

A

Sodium Nitroprusside

39
Q

What would you give to someone experiencing sodium & water retention while on Sodium Nitroprusside?

A

Loop diuretics

40
Q

What is the active component of sodium nitroprusside?

A

Nitric Oxide

41
Q

What does nitric oxide activate?

A

an enzyme present in VSM

42
Q

Cyanide groups will be converted to thiocyanate via what organ?

A

Liver

43
Q

What is the cofactor?

A

Thiosulfate.

44
Q

How is thiosulfate excreted?

A

Kidneys

45
Q

What are 3 ADRs of Sodium Nitroprusside?

A

-excessive hypotension
- cyanide poisoning
-thiocyanate toxicity

46
Q

Thiocyanate toxicity can occur if drug is given longer then what?

A

3 days

47
Q

Thiocyanate toxicity can cause sever CNS ADRs such as:

A

-disoriented, hallucinations, delusions

48
Q

If cyanide poisoning occurs, what should you do?

A

Discontinue nitroprusside and co-administer thiosulfate

49
Q

Thiocyanate levels need to be:

A

below 0.1 mg/ml