Drugs of the Cardiovascular System – The Vasculature Flashcards Preview

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Flashcards in Drugs of the Cardiovascular System – The Vasculature Deck (37)
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1

Name three drug classes that interfere with the renin-angiotensin system.

Renin inhibitors
ACE inhibitors
Angiotensin receptor blockers

2

Describe the action of aldosterone in collecting duct tubule cells.

Aldosterone passes through the plasma membrane and binds to mineralocorticoid receptors intracellularly and increases the synthesis of Na+ channels and Na+/K+ pumps
This causes an increase in sodium reabsorption

3

Give an example of an ACE inhibitor.

Enalapril
Tend to end in il

4

What are the anti-hypertensive effects of ACE inhibitors?

They reduce the production of angiotensin II, which is a potent vasoconstrictor
It also reduces the production of aldosterone, thus reducing salt and water retention
This means that there is a decrease in blood volume, hence a decrease in venous return

5

What law links venous return to contractility?

Starling’s Law

6

What is diabetic nephropathy caused by?

It is due to significant damage to the kidney glomerulus because of toxic products

7

Why are ACE inhibitors used in diabetic nephropathy?

ACE inhibitors reduce the angiotensin II-mediated vasoconstriction of the efferent arteriole
This reduces the blood pressure at the glomerulus and hence reduces the accumulation of toxic products at the glomerulus

8

Give an example of an angiotensin receptor blocker.

Losartan

9

What is the most common side effect of ACE inhibitors?

COUGH due to stopping breakdown of bradykinin which causes cough

10

State some other side effects of ACE inhibitors and ARBs.

Hypotension
Urticaria/Angioedema (ACEi – very rare)
Hyperkalaemia
Fetal injury
Renal failure in patients with renal artery stenosis (due to both)

11

What type of calcium channel blocker is more selective for blood vessels? Give an example.

Dihydropyridines – nicardipine and amlodipine

12

Which part of the calcium channel do the different CCBs bind to?

Dihydropyridines bind to the extracellularly component of the calcium channel
Diltiazem and verapamil binds to the intracellular component so for a CCB to have an effect on the heart it needs to be able to penetrate the membrane and act on the receptor inside the cell

13

Why are non-rate slowing CCBs preferred to rate-slowing CCBs in the treatment of hypertension and heart failure?

They have a more powerful effect on vascular smooth muscle

14

What type of receptor is a beta adrenoceptor?

G-protein coupled receptor

15

What are the effects of noradrenaline that cause an increase in blood pressure?

Increase in heart rate and cardiac contractility (leads to increase in CO) via beta-1 receptors in the heart
Stimulation of beta-1 receptors in the kidneys promotes renin release --> increase in angiotensin II

16

What is hypertension in younger patients normally caused by?

Increased sympathetic drive

17

State some uses of beta-blockers.

Angina
Post-MI
Cardiac dysrhythmias
Chronic heart failure
Hypertension
Also thyrotoxicosis, glaucoma, anxiety states, migraine prophylaxis, benign essential tremor

18

Give an example of a cardio-selective beta-blocker.

Atenolol

19

What are mixed beta-alpha blockers? Give an example.

They are beta-1, beta-2 and alpha-1 blockers
Carvedilol
You get extra vasodilation due to alpha-1 blockade

20

Give an example of an alpha-1 blocker.

Prazosin

21

Give an example of a non-selective alpha blocker.

Phentolamine

22

Why is it important for alpha-1 blockers to be selective?

Alpha-2 receptors are the negative feedback receptors of the SNS
Blocking them will result in enhancement of sympathetic activity

23

What is step 1 in the NICE guidelines for treatment of hypertension?

< 55 years = ACEi + ARB
>55 years or Afro-Caribbean of any age = CCBs + thiazide-type diuretics

24

What is step 2?

ACEi or ARB
AND CCB or thiazide diuretic
Basically combine them

25

What is step 3?

ACEi/ARB
CCB
Thiazide diuretic

26

What is step 4?

Further diuretic therapy (low-dose spironolactone)
Alpha or beta-blocker
Called resistant hypertension

27

What is spironolactone?

It is an aldosterone receptor antagonist

28

What is chronic heart failure?

Impaired cardiac function due to ischaemic heart disease, hypertension or cardiomyopathy that results in fluid retention, oedema and fatigue

29

Which drugs are normally used on patients with chronic heart failure?

ACEi
ARB
Beta-blockers
Spironolactone

30

Hypertension definition

BP consistently above 140/90