12: Vasculature Drugs

Question 1

Explain the MOA of ACE inhibitors

Answer 1

• inhibit ACE–> reduce Angiotensin II levels
• leading to inhibition of AgII mediated vasoconstriction and direct +indirect Salt+Water retention,
• less TPR, less blood volume, less afterload+ less preload (decrees in venous return)

Question 2

When do you use ACE inhibitors?

Answer 2

1. HTN
2. Hear Failure
3. post MI
4. diabetic nephropathy
5. progressive renal insufficiency
6. patients at high risk of cardiovascular diseas

Question 3

What are the side effects of use of ACEi?

Answer 3

Gnerally well tolerated

1. Hypotension
2. Might lead to cough due to accumulation of Bradykinin (no break down by AgII)
3. Hyperkalaemia (Na+/K+ ATPase–> no K+ excretion)
4. Renal failuare in patients with renal artery stenosis (no AgII mediated vasoconstriction in the efferent glomerular arteriole–> drop in Glumerular filtration pressure)

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Question 4

Name an example of an ACE inhibitor

Answer 4

Enalapril

Question 5

Name an example of an Angiotensin Receptor Blocker

Answer 5

Losartan

Question 6

Explain the MOA of Losartan

Answer 6

Losartan= Angiotensin Receptor Blocker

Blocks the vasculature and renal effects of AgII by antagonizing Type 1 Angiotensin II receptors (AT₁)

Question 7

Explain the use and side effects of losartan

Answer 7

1. Use in
   
   • HTN
   • Heart Failure
2. Side effects
   
   • Hypotension
   • Hyperkalaemia
   • Renal failure in patients with renal artery stenosis

Question 8

Name an example of a Dihydropiridines (DHP)?

What kind of class is it?

Answer 8

It is a non-rate slowing CCB

e.g. Amlodipine

Question 9

Which of the calcium channel blockers would you use to treat hypertension?

Answer 9

Dihydropyridines (DHPs)–> no negative inotropy

• •More selective for blood vessels
• e.g. Amlodipine

Question 10

What are the side effects of Dihydropyridines?

Answer 10

Very potent vasodilators:

• Hypotension
• reflex tachycardia

Question 11

Why do you not give ACEi/Angiotensin receptor blockers to people older than 55 or from Afro-carribean origin?

Answer 11

1. Thought to have lower Renin activity
2. In Elderly: HTN is thought to be mainly due to atherosclerosis,
   
   • lesser effect of interference with the RAAS system

Question 12

Which anti-hypertensive drugs would you favour for someone with Heart Failure?

Answer 12

1. RAS over CCB and ß blocker
2. Diuretic over RAS

Question 13

Which anti-hypertensive drug class would you favour for someone with a stroke?

Answer 13

1. CCB over RAS inhibitor
2. Diuretic over RAS inhibitor
3. RAS inhibitor over ß-blocker

Question 14

Explain the use of a1 antagonists as a treatment in Hypertension

Answer 14

Cause Vasodilation –> reduction in TPR

Question 15

Name examples of a-antagonists

Answer 15

1. a1-selective= Prazosin
2. a1+2= Phentolamine