Wk 5 HTN

Question 1

Understand that elevated blood pressure/hypertension is a cardiovascular risk factor

Answer 1

HTN is a risk factor for a series of CVD:

• stroke (↑BP causes vessel rupture or clot formation)
• heart failure (↑BP causes cardiac hypertrophy)
• myocardial infarction (cardiac hypertrophy)
• renal failure (↑BP causes arteries around the kidneys to narrow)

Question 2

Discuss the non-pharmacological and pharmacological ways of treating hypertension

Answer 2

Non-pharmacological:

• lifestyle
• diet, healthy eating
• ↓ drinking, smoking
• physical activity

Pharmacological:
ACEI: ramipril, captopril, perindopril
- ↓angiotensin II, ↑bradykinin
- ↓[vasoconstriction, aldosterone release, Na+/H2O reabsorption]
- cough, hypotension, hyperkalemia, renal impairment
- CON: renal impairment, elderly, pregnancy

A2RA: irbesartan, candersartan

• same as ‘ACEI’
• cough, hypotension, hyperkalemia, renal impairment
• CON: renal impairment, elderly, pregnancy

Calcium channel blocker/CCB
- dihydropyridine: amlodipine, felodipine, nifedipine
- non-dihydropyridine: diltiazem, verapamil
[DHP CCB is more potent in vasodilation than non-DHP]
- MOA: primarily inhibit calcium entry into the vascular smooth muscle cells of blood vessels + cardiac muscle cells
- AEs: vasodilatory effects, including headache, flushing, dizziness, hypotension, peripheral oedema

Beta adrenoceptor antagonist/BB
- propranolol, atenolol, metoprolol
- MOA:
> block beta receptors in the heart (B1 receptor), lungs (B2 receptor), bladder (B3 receptor) etc
> ↓ HR, BP, cardiac contractility
- AEs: bradycardia, hypotension, bronchospasm, cold extremities

Diuretics
- MOA: ↓ Na+ & H2O reabsorption,
- Loop diuretics: frusemide
> potent, site: loop of henle
- thiazide diuretics: hydrochlorothiazide
> moderately potent, site: distal convoluted tubule
- potassium-sparing diuretics: spironolactone, amiloride
> weak, site: late distal convoluted tubule
- AEs:
> loop & thiazide: hypokalemia, hyponatraemia, hyperuricemia, hyperglycaemia
> potassium: hyperkalemia

Question 3

What is Triple Whammy effect?

Answer 3

• ACEI/A2RA: cause vasodilation to efferent renal arteriole → ↓ glomerular filtration rate
• NSAIDs: (including COX 2 inhibitors): cause vasodilation to afferent renal arteriole [by reducing prostaglandin]
• Diuretics: cause hypovolemia