Hypertension Flashcards
(36 cards)
Why is controlling bp important
Reduction in CV damage Preservation of renal function Limit or reverse left ventricular hypertrophy PRevention of IHD Reduction in mortality due to strole/MIs
BP hypertension in clinic?
140/90
BP in home/ambukatory
130/85
What BP requires same day referral
> 180/120
When is renin released by kidney
When it detects low levels of sodium, and when it detects low blood pressure
What is the RAAS system
Renin turns angiotensin (formed by liver) into angiotensin 1. ACE then turns this into angiotensin 2.
Angiotensin 2 causes vasoconstriction and acts on adrenal gland to release aldosterone.
Aldosterone then acts on distal convuluting tubule of kidney and early collecting duct of the kidney to cause sodium retention and potassium loss. This then increases retention of water which increases circulating volume
Role of ACEI
Inhibit ACE. Therefore:
- Reduce arterial and venous vasoconstriction
- Reduced aldosterone production
Side effects of ACEI
Potentiate bradykinin which leads to cough
May increase Potassium (interaction with salt KCL substitute)
Angioedema (increased incidence in black patients)
When should ACEI be avoided
Renovascular disease (bilateral renal artery stenosis) -Renin-dependent hypertension. ACEI lead to renal underperfusion and severe hypotension
What should you monitor before and during treatment of ACEI
- eGFR
- K+
What is the best antihypertensive in patients with diabetes and why
ACEi
They’re effective in preventing nephropathy in DM
Action of AT1 receptor antagonists
Block the effect of angiotensin 2 which acts at the AT1 receptor to cause vasoconstriction
Do AT1 receptor antagonists give rise to cough
no
Two classes of calcium channel inhibitors
Rate limiting (e.g. verapamil): have greater effecrs on cardiac tissue
Dihydropyridines (e.g. amlodipine) more on vascular smooth muscle
Mechanism of action of calcium channel inhibitors
Inhibit voltage operated Ca2+ channels on vascular smooth muscle leading to vasodilatation and reduction in BP
Action of thiazide like diuretics and what line treatment it is
Second line
Inhibit Na+/Cl- trasnporter system in distal convuluting tubule which leads to a reduction in circulating volume. It also causes vasodilatation
Are thiazide like diuretics effective in moderate renal impairment
No
-But measure eGFR before and during use
Important side effects of thiazide like diuretics
Hypokalaemia
Postural hypotension
Impaired glucose control
Do not use in gout
When not to use thiazide like diuretics
Gout
Mode of action of alpha blockers
Competitive receptor antagonists of a1 adrenoceptors which cause vasodilation
Why are alpha blockers last choice antihypertensives
Widespread side effects, which makes them poorly tolerated
Mode of action of beta blockers
Mechanism unclear -
-Reduction in sympathetic drive to the heart, reducing cardiac output
-Reduction in sympathetically evoked renin release
WHen are beta blockers contraindicated
Asthma
- Caution in COPD
- Heart block
Side effects of calcium channel blockers
Peripheral oedema
some- constipation
