Pharmacological Treatment of Hypertension Flashcards

1
Q

Criteria for treatment of stage 1 hypertension

A
  • end organ damage and under 80?
  • CVS disease?
  • renal disease?
  • diabetes?
  • 10 year CV risk >10%?
  • if yes: lifestyle changes and therapeutic interventions
  • if no: lifestyle changes/monitor BP
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2
Q

List the anti-hypertensive therapeutics

A
  • ACE inhibitors
  • ARBs
  • diuretics
  • CCBs
  • a-adrenergic receptor blockers
  • b-adrenergic receptor blockers
  • spironolactone/potassium-sparing diuretics
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3
Q

What drugs target the kidneys?

A
  • ACE inhibitors
  • ARBs
  • thiazide diuretics
  • spironolactone and K+ sparing diuretics
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4
Q

Explain the mechanism of action of ACE inhibitors

A

prevents the conversion of Angiotensin I to Angiotensin II in the RAAS

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5
Q

What effect do ACE inhibitors have on the RAAS pathway?

A
  • decrease vasoconstriction decreasing TPR
  • decrease water and salt retention decreasing ECV
  • overall decreasing BP
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6
Q

What are some examples of ACE inhibitors?

A
  • captopril
  • enalapril
  • perindopril
  • lisinopril
  • ramipril
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7
Q

What effect do ACE inhibitors on the kinin-kallikrein system?

A
  • increases bradykinin
  • prevents conversion of bradykinin to its inactive metabolite
  • increases vasodilation
  • decreases TPR
  • overall decreases BP
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8
Q

Side effect of ACE inhibitors?

A
  • dry cough
  • due to increased bradykinin which can cause bronchoconstriction
  • patient can be prescribed ARB instead
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9
Q

Explain the mechanism of action of ARBs

A

Blocks the AT1 receptors that angiotensin II bind to, blocking their action

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10
Q

What effect does ARBs have?

A
  • decreases vasoconstriction decreasing TPR
  • decreases water and salt retention decreasing ECV
  • overall decreasing BP
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11
Q

Why do patients not experience a dry cough with ARBs?

A

the drug has specific effects on AT1 and so has no effect on bradykinin

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12
Q

What are the 3 types of diuretics?

A
  • loop diuretics
  • thiazide diuretics
  • K+ sparing diuretics
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13
Q

What are some examples of ARBs?

A
  • losartan
  • irbesartan
  • valsartan
  • olmesartan
  • candesartan
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14
Q

Explain the mechanism of action of loop diuretics

A
  • inhibit NKCC in thick ascending limb of Loop of Henle

- reduces reabsorption of Na, K and Cl

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15
Q

What diseases are loop diuretics used to treat?

A
  • acute pulmonary oedema
  • chronic heart failure
  • cirrhosis of liver
  • nephrotic syndrome
  • renal failure
  • hypertension (only with impaired renal function)
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16
Q

What are some examples of loop diuretics?

A
  • furosemide

- bumetanide

17
Q

Explain the mechanism of action of thiazide diuretics

A
  • inhibit NCC
  • reduces reabsorption of Na and Cl
  • can also cause vasodilation
18
Q

What is a side effect of thiazide diuretics?

A

erectile-dysfunction

19
Q

What are some examples of thiazide diurectics?

A
  • bendroflumethiazide

- hydrochlorothiazide

20
Q

Why must K+ sparing diuretics be used in combination with loop/thiazide diuretics?

A
  • would cause hyperkalaemia alone

- combinations balance plasma concentration of K+

21
Q

Explain the mechanism of action of K+ sparing diuretics

A

Aldosterone antagonists:
- competitively inhibit mineralcorticoid receptor

ENaC inhibitors:
- block epithelial Na+ channel

22
Q

What are some examples of aldosterone inhibitors?

A
  • spironolactone

- eplerenone

23
Q

What are some examples of ENaC inhibitors?

A
  • amiloride

- triamterene

24
Q

Locations of adrenoreceptors

A
  • a1: vascular smooth muscle
  • a2: brain
  • B1: heart
  • B2: vascular smooth muscle
25
Q

Explain the mechanism of action of a-adrenoreceptor antagonists

A
  • decreases vasoconstriction
  • decreases TPR
  • decreases BP
  • non-selective a-antagonists cause rapid decrease in BP which can trigger tachycardia and decreased negative feedback of NA release
  • selective a1 antagonists cause less tachycardia as they do not bind a2 receptors
  • only used in severe hypertension
26
Q

Explain the mechanism of action of b-adrenoreceptor antagonists

A
  • decrease HR/force of contraction
  • decreases cardiac output
  • decreases BO

also

  • inhibits renin release from granular cells
  • decreases angiotensin II
  • decreases vasoconstriction
  • decreases salt retention
27
Q

When are b-adrenoreceptors used?

A

for antihypertensive patients with additional need for B-blockade such as angina/heart failure

28
Q

What are some additional examples of DHP CCBs?

A
  • clevidipine
  • nicardipine
  • nimodipine
29
Q

Describe the effect CCBs have

A

Cardiac:

  • decrease contractility
  • decrease HR
  • decrease conduction velocity
  • decrease CO
  • decrease BP

Smooth muscle:

  • decrease coronary artery constriction
  • decrease peripheral vessel constriction
  • decrease TPR
  • decrease BP
30
Q

What are the advantages of multi-drug treatment?

A
  • reduced mortality/morbidity
  • each drug class works at different sites, can achieve BP treatment quicker
  • reduces dose burden of individual drugs minimising side effects
31
Q

What are the disadvantages of multi-drug treatment?

A
  • concordance a problem
  • forgetting to take drugs
  • side effects more frequent
  • drug costs to NHS
32
Q

Describe the stepped process of treatment of hypertension

A

If under 55 and no afro-carribean descent
If type 2 diabetes:
- step 1: ACE inhibitor or ARBs
- step 2: add CCBs or thiazide diuretic
- step 3: ACEi, ARB, CCB and thiazide diuretic
- step 4: confirm resistant hypertension. Confirm elevated BP with HBPM/ABPM
- add low dose spironolactone if blood K+ level is less than 4.5mmol
- or add a-blocker or b-blocker if blood K+ level is more than 4.5mmol

If over 55/afro-carribean descent:
- same protocol but CCB is first given