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Flashcards in Hypertension Deck (43):
1

What is the resting BP in hypertension?

SBP > 140mmHg
DBP > 90mmHg

2

Organs that will be damaged by hypertension

heart, brain, retina, kidney, dissecting aortic aneurysm

3

Tissues damaged due to artherosclerosis

Coronary, cerebral vessels, carotids

4

What two broad changes occur in the cardiovascular system in response to hypertension?

Cardiac and vascular hypertrophy

5

Lifestyle changes to treat hypertension?

regular exercise, reduced dietary salt, decreased alcohol, lower weight

6

Groups of commonly used antihypertensive drugs

angiotensin converting enzyme inhibitors and angiotensin antagonists
beta blockers
calcium channel blockers
diuretics (thiazides, loops, K+ sparing)
extras

7

Where does angiotensinogen come from?

liver

8

what converts angiotensinogen into angiotensin I?

renin from juxta-glomerular cells

9

what converts angiotensin I to angiotensin II?

ACE (lungs and elsewhere)

10

What does angiotensin II cause?

vasoconstriction (has direct effect on lumen diameter), aldosterone output, sodium and water retention

11

what converts bradykinin to inactive products?

ACE (lungs and elsewhere)

12

where are angiotensin I and II found?

in the bloodstream

13

What do ACE inhibitors do? -opril, -april

- prevent angiotensin II formation and inhibit bradykinin breakdown, resulting in lower peripheral resistance and sodium and water excretion

14

What are the indications for use of ACE inhibitors?

hypertension, heart failure, preserve renal function in diabetes (diabetic nephropathy)

15

contraindications for ACE inhibitors?

- less effective in patients of African origin
- renal failure if there is also renal artery stenosis
- avoid in pregnancy

16

Common side effects of ACE inhibitors?

cough (from high bradykinin), headache, marked hypotension (start with low dose), hyperkalaemia (beware of K+ supplements or K+ sparing diuretics)

17

infrequent side effects of ACE inhibitors?

rash/itch, taste disturbances, angioedema

18

Example of ACE inhibitor?

perindopril

19

Example of an angiotensin receptor blocker (ARBs)?
- sartans

irbesartan

20

What do ARBs do?

are angiotensin I receptor antagonists: inhibit angiotensin -induced vasoconstriction and aldosterone output; effect is reduced total peripheral resistance and increased Na+ and water excretion *no dry cough as seen in ACE inhibitors

21

What are the indications for use of ARBs?

hypertension, heart failure, diabetic nephropathy, for patients intolerant to ACE inhibitors e.g. cough

22

adverse effects of ARBs?

hypotension (less than ACE inhibitors), hyperkalaemia, avoid in pregnancy, beware of renal artery stenosis

23

What do calcium channel blockers do?

block L-type (voltage operated) calcium channels, reduces Ca2+ entry into the vascular/cardiac cells *not skeletal muscle, therefore there is a reduction in intracellular calcium = vasodilation and reduced cardiac contractility and reduced atrioventricular conduction

24

2 examples of calcium channel antagonists? Key difference between the two?

verapamil - reduces venous pressure (preload), has stronger effects on the heart
and amlodipine - reduces arteriolar pressure (afterload), stronger effects on HR (up), BP (down) and TPR (down)

25

what are indications for calcium channel blockers/antagonists?

hypertensions, angina, tachydysrhythmias (TDRs)

26

What are contraindications for calcium channel blockers?

heart failure or beta-blockers (with verapamil)

27

Side effects of calcium channel blockers

- cardiac depression (both rate and force reduced), bradycardia (therefore contraindicated in heart failure)
- flushing, oedema, dizziness, headache
- constipation, nausea

28

what do diuretics do?

- increase water and sodium excretion from the kidney
- reduce circulating blood volume in hypertension; there is an initial drop in CO and; in longer term CO and TPR return to normal levels

29

What do thiazides e.g. hydrochlorothiazide and indapamide act on?

distal tubule

30

Example of a diuretic?

frusemide, more potent than thiazides, used in acute scenarios

31

What do loop diuretics such as frusemide act on?

loop of Henle

32

Uses of thiazides such as hydrochlorothiazide and frusemide?

- mild to moderate hypertension
- oedema due to: 1)congestive heart failure (+/- hypertension), 2) +/- pulmonary congestion and renal or liver disease

33

Side effects of thiazides generally?

rash, hypokalaemia, hyperuricaemia, glucose intolerance, hyperchlesterolaemia

34

Side effects of loop diuretics?

- hypovolaemia: dizziness, weakness, nausea, cramps, hypotension
- hearing loss
- increased magnesium, calcium excretion

35

What is an important drug interaction with the use of diuretics?

Digoxin - toxicity is greatly increased
(also consider K+ supplementation or combination with K+ sparing diuretics)

36

What do beta-adrenoceptor antagonists do - what are their effects?

decrease sympathetic input to the heart (therefore reduced CO and HR - and TPR to a lesser extent), inhibit renin release by decreasing Ang II levels, reduce sympathetic outflow from CNS if lipid soluble

37

2 examples of beta-adrenoceptor antagonists and their selectivities?

Propranolol - non selective beta 1 and 2 antagonist
Atenolol - beta 1 selective antagonism

38

Clinical uses for beta adrenoceptor antagonists?

angina, post myocardial infarct, hypertension, dysrhythmias, clinically stable heart failure

39

Factors to consider when choosing a hypertensive

-patient's CV risk profile
-presence of target organ damage, renal disease, diabetes
-presence of coexisting conditions which may favour/limit use of particular classes (diabetes, respiratory)
-individual patient variability to different classes
-adverse effects
-interactions with other co-prescribed drugs
-cost, compliance

40

Most effective combination for hypertension?

ACE inhibitor or ARB
+ calcium channel blocker

41

Other effective combination therapies?

- ACE inhibitor/ARB + thiazide diuretic esp. in heart failure or post stroke (low dose thiazide diuretic for people aged 65+)
- ACE inhibitor/ARB + beta-blocker esp. post MI or heart failure
- beta-blocker + dihydropyridine calcium channel blocker esp. coronary heart disease
- thiazide diuretic + Ca2+ channel blocker
- thiazide diuretic + beta-blocker *not recommended in people with glucose intolerance, metabolic syndrome or established diabetes

42

In newly diagnosed hypertension, is it best to start with mono or combination therapy?

One drug to start, then 2 then 3. If after 3, target BP is still not reached, then refer to a specialist.

43

Dangerous combinations to avoid

- ACE inhibitor/ARB antagonist + K+-sparing diuretic (risk of hyperkalaemia)
- verapamil + beta-blocker (risk of heart block)
- ACE inhibitor + Ang II receptor antagonist (increases risk of hypertensive symptoms, syncope and renal dysfunction)