Drugs on vessels

Question 1

How is muscle contraction triggered (Basic)?

Answer 1

Ca2+ enters via T-tubule, once threshold reached activates Ryanodine receptor, causing influx (70% of needed Ca2+) of Ca2+ from sarcoplasmic reticulum – Ca2+ causes contraction.

Question 2

How are ion levels in myocytes maintained?

Answer 2

ATPases drive majority of Ca2+ back into SR
Ca2+/Na+ transporters remove excess Ca2+
Na+/K+ ATPases remove excess Na+

Question 3

What is considered hypertension?

Answer 3

140/90 mmHg OVER MULTIPLE MEASUREMENTS (OVER TIME)

Question 4

What the common categories of anti-hypertensives?

Answer 4

ACE inhibitors (E.G Enalapril)
Calcium channel blockers (E.G Amlodipine)
Angiotensin receptors blockers (E.G Losartan)
Alpha blockers
Diuretics
Beta blockers

Question 5

What are the ‘stages’ of hypertension treatment?

Answer 5

1 – ACEi or ARB for under 55s / CCB or thiazide diuretics for over 55 AND afro Caribbean

2 – ACEi ARB group add CCB or Thiazide diuretic, CCB Diuretic group add ARB

3- Further addition of same drugs

4- Resistant hypertension – consider adding low-dose spironolactone/alpha or beta blocker

Question 6

Why are ACEi and ARBs not first line in over 55s and afro Caribbean’s?

Answer 6

Plasma renin is low in these groups but is less of a determinant in Aii or BP – the treatments are therefore less effective in these groups.

Question 7

Why is it good to give ACE I or ARB alongside diuretics?

Answer 7

Diuretics cause drop in Na+, this causes compensatory rise in RAS activity that is counteracted by ACE I and ARBs.

Question 8

What is a side effect of ACE inhibitors?

Answer 8

Cough – 25% patients present with it. Occurs due to inhibition of bradykinin breakdown which is ordinarily performed by ACE.

Question 9

What is a side effect of ACE Is and ARBs?

Answer 9

Hyperkalaemia – Less aldosterone is produced, less Na+/K+ proteins in membrane – K+ retained

Renal failure if given with pre-existing renal artery stenosis as glomerular pressure for filtration not achieved. (They cause efferent arteriole dilation)

Question 10

What are the anti-hypertensive effects of ACE inhibitors?

Answer 10

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

Question 11

How does Lorsartan work?

Answer 11

Competetively antagonises AII at AT1 (Angiotensin II type 1) receptor, converted into more potent metabolite that acts as an insummountable AII antagonist