BP and Heart Failure

Question 1

How can the causes of hypertension be classed?

Answer 1

Primary = high BP without any single evident cause

Secondary = high BP with a discrete, identifiable underlying cause

Question 2

Decisions about hypertensive drug therapy are informed by what?

Answer 2

BP level and total cardiovascular risk

Question 3

Be aware of non-pharmacological management of hypertension

Answer 3

Lifestyle therapy

Pt education

Maintain normal body weight – BMI 20-25

Reduce salt intake to <6g/day

Limit alcohol consumption to <3units/day for men, <2 units/day for women

Engage in regular aerobic physical exercise for >30 minutes/day

Consume >5 portions of fresh fruit/vegetables daily

Reduce intake of total and saturated fat

Smoking cessation

Relaxation therapies

Question 4

Discuss ACEi

Answer 4

Ramipril

Sites of action – competitively inhibitors of ACE

Results = arteriolar vasodilation, venodilation, aldosterone reduced

Side effects = dry cough, angio-oedema, renal failure, hyperkalaemia

Question 5

Discuss angiotensin receptor blockers (ARB)

Answer 5

Losartan

Site of action = bind AT1 receptor

Results = Inhibit vasoconstriction and aldosterone stimulation caused by angiotensin II

Side effects = renal failure, hyperkalaemia

Question 6

Outline Ca channel blockers

Answer 6

Amlodipine

Site of action = alpha subunit of L-type Ca channels

Results = reduced cellular Ca entry - vasodilates peripheral, coronary and pulmonary arteries, depresses SA node and slows AV conduction

Side-effects = Bradycardia (tachycardia in dihydropyridines), oedema, flushing and sweating.

Question 7

Discuss thiazide and thiazide-like diuretics

Answer 7

Bendroflumethiazide

Site of action = distal tubule

Results = decreased tubular Na reabsorption

Side effects = hypokalaemia, increased urea and cholesterol, impaired glucose tolerance

Question 8

Outline NICE guidance regarding hypertension

Answer 8

Under 55 = start on ACEi

Over 55/black African/Caribbean = start on Ca channel blocker

Then add ACEi or Ca channel blockers

Then add Thiazide like blocker

Then add beta blocker

Question 9

Discuss alpha blockers

Answer 9

Doxazosin

Site of action = selective antagonism at post synaptic alpha-1 adrenoceptors

Results = reduce peripheral vascular resistance

Side effects = postural hypotension, headache, oedema

Question 10

Outline beta blockers

Answer 10

Atenolol, bisoprolol

Site of action = block norepinephrine and epinephrine (adrenaline) binding beta receptors on nerves

Results = reduce HR and CO, inhibit renin release

Side effects = lethargy, reduced exercise tolerance, bradycardia, impaired glucose tolerance

Question 11

What is the aetiology of heart failure?

Answer 11

Ischaemic heart disease

Hypertension

Cardiomyopathies

Valve disease

Question 12

Summarise the drug therapies used in heart failure

Answer 12

Diuretics – loop diuretics, remove oedema, spironolactone

ACE (-)/ARB

β-blocker

Ivabradine - reduced HR by inhibition of funny channels, used along side beat blockers

Sacubitril - inhibits enzyme neprilysin, responsible for degradation of ANP/BNP

Hydralazine/Nitrate – primaily used in black pts

Antiarrhythmics

Question 13

Summarise the non-pharmacological measures used to treat heart failure

Answer 13

Intervention = valve surgery, heart transplant, mechanism assist devices

Pacemakers

Implantable defibrillators

Lifestyle modifications = reduce salt, alcohol, BP, increase exercise