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LCRS 1 - Pharmacology Part 2 > Drugs of the Cardiovascular System – The Vasculature > Flashcards

Drugs of the Cardiovascular System – The Vasculature Flashcards

1
Q

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

A

Renin inhibitors
ACE inhibitors
Angiotensin receptor blockers

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2
Q

Describe the action of aldosterone in collecting duct tubule cells.

A

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

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3
Q

What are the uses of ACE inhibitors?

A 
Hypertension  
Heart Failure  
Diabetic Nephropathy 
Post-MI
Progressive Renal Insufficiency  
Patients at high risk of cerebrovascular disease
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4
Q

Give an example of an ACE inhibitor.

A

Enalapril

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5
Q

What are the anti-hypertensive effects of ACE inhibitors?

A

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

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6
Q

What law links venous return to contractility?

A

Starling’s Law

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7
Q

What is diabetic nephropathy caused by?

A

It is due to significant damage to the kidney glomerulus because of toxic products
NOTE: hyperglycaemia increases the risk of exposure to oxygen free radicals

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8
Q

Why are ACE inhibitors used in diabetic nephropathy?

A

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

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9
Q

Give an example of an angiotensin receptor blocker.

A

Losartan

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10
Q

What is the most common side effect of ACE inhibitors?

A

COUGH

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11
Q

State some other side effects of ACE inhibitors and ARBs.

A 
Hypotension  
Urticaria/Angioedema (ACEi – very rare) 
Hyperkalaemia  
Fetal injury 
Renal failure in patients with renal artery stenosis (due to both)
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12
Q

Describe the excitation-contraction coupling of vascular smooth muscle cells.

A

Deplarisation causes the opening of voltage-gated calcium channels (VGCC)
This leads to calcium influx
The calcium then binds to calmodulin forming a Ca2+-CaM complex
This complex activates Myosin Light Chain Kinase (MLCK), and the MLCK-mediated phosphorylation leads to smooth muscle contraction

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13
Q

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

A

Dihydropyridines – nicardipine

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14
Q

Give two examples of non-rate slowing CCBs.

A

Nicardipine
Nitrendipine
Amlodipine
Nisoldipine

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15
Q

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

A

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

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16
Q

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

A

They have a more powerful effect on vascular smooth muscle

17
Q

What type of receptor is a beta adrenoceptor?

A

G-protein coupled receptor (Gs protein linked)

18
Q

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

A

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

19
Q

What is hypertension in younger patients normally caused by?

A

Increased sympathetic drive

20
Q

State some uses of beta-blockers.

A 
Angina 
Post-MI
Cardiac dysrhythmias  
Chronic heart failure
Hypertension  
Also thyrotoxicosis, glaucoma, anxiety states, migraine prophylaxis, benign essential tremor
21
Q

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

A

Atenolol

22
Q

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

A

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

23
Q

Give an example of an alpha-1 blocker.

A

Prazosin

24
Q

Give an example of a non-selective alpha blocker.

A

Phentolamine

25
Q

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

A

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

26
Q

Give an example of a drug that is used to treat migraine and explain how it works.

A

Sumatriptan
It is a 5-HT (serotonin) receptor agonist, which causes vasoconstriction of some of the large arteries in the brain and inhibits trigeminal nerve transmission
NOTE: painful stimuli is transferred by the trigeminal nerve and profound vasodilation is also associated with migraine

27
Q

When is sumatriptan contraindicated?

A

Coronary disease

28
Q

What are the side effects of sumatriptan?

A

Dizziness, drowsiness, asthenia/fatigue

29
Q

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

A

< 55 years = ACEi + ARB

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

30
Q

What is step 2?

A

ACEi or ARB

AND CCB or thiazide diuretic

31
Q

What is step 3?

A

ACEi/ARB
CCB
Thiazide diuretic

32
Q

What is step 4?

A

Further diuretic therapy (low-dose spironolactone)

Alpha or beta-blocker

33
Q

What is spironolactone?

A

It is an aldosterone receptor antagonist

34
Q

What is chronic heart failure?

A

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

35
Q

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

A

ACEi
ARB
Beta-blockers
Spironolactone

LCRS 1 - Pharmacology Part 2 (19 decks)

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