Drugs Used In Hypertension

Question 1

What is the single biggest cause of death worldwide?

Answer 1

Hypertension

Question 2

What is the first line treatment for hypertension in patients below the age of 55? 2

Answer 2

1. Angiotensin converting enzyme (ACE) inhibitors

2. Angiotensin receptor blockers (ARBs)

Question 3

Where is renin produced?

Answer 3

Juxtaglomerular cells

Question 4

What does renin do?

Answer 4

Renin convert angiotensinogen into angiotensin I

Question 5

Where is ACE found?

Answer 5

On the surface of the epithelial cells in the capillaries

Question 6

What ACE do?

Answer 6

Converts angiotensin I into angiotensin II

Question 7

Describe the functions of angiotensin II 5

Answer 7

1. Causes vasoconstriction in blood vessels; increases resistance
2. Stimulates the pituitary gland to release ADH (increasing water reabsorption); increased SV
3. Stimulates the adrenal gland to release aldosterone (increasing Na reabsorption; increased SV
4. Increases Na/H2O reabsorption in the kidneys; increased stroke volumes
5. Increased resistance and increased SV increases BP

Question 8

Why don’t we use ACE inhibitors and ARBs in patients over the age of 55?

Answer 8

Over the age of 55 the renin-angiotensin system isn’t as functional. We therefore use calcium channel blockers.

Question 9

Describe the MOA of thiazide and other diuretics? 4

Answer 9

Diuretics cause a decrease in
1. Blood volume
2. Venous return 
3. Cardiac output 
 Which leads to a decrease in blood pressure

Question 10

Explain a possible theory for diuretics causing vasodilation 3

Answer 10

1. Diuretics result in the reduction in smooth muscle Na
2. This may result in a secondary reduction of intracellular Ca
3. Muscle may therefore be less responsive to vasoconstriction

Question 11

What are the side effects of diuretics? 3

Answer 11

Diuretics may result in :

1. Hypokalaemia
2. Diabetes mellitus
3. Gout

Question 12

Who is thiazide diuretics useful in?

Answer 12

Thiazide diuretics is particularly useful in older patients (>55 )

Question 13

Give two examples of thiazide like diuretics 2

Answer 13

1. Hydrochlorothiazide

2. Indapamide

Question 14

Give an example of a potassium sparing diuretic

Answer 14

Amiloride

Question 15

Explain the effects of β adrenoceptor antagonist 2

Answer 15

1. β blockers initially reduce BP by decreasing CO.
2. It is also suggested that β blockers, antagonize β1 receptors in the juxtaglomerular cells, inhibiting the release of renin

Question 16

What are the disadvantages of β blockers?7

Answer 16

1. Cold hands
2. Fatigue
3. Provocation of asthma
4. Heart failure
5. Conductance block
6. Raise serum triglyceride levels
7. Decrease high density lipoprotein levels

Question 17

How can some of the side effects of β blockers be prevented?

Answer 17

We can use cardio-selective hydrophillic drugs (drugs without liver metabolism or brain penetration) such as atenolol.

Question 18

How does the body increase BP? 3

Answer 18

1. Stimulation of β1 receptors increases CO
2. Stimulation of α1 receptors causes vasoconstriction in smooth muscle of blood vessels increasing resistance
3. Increased renin -> increased angiotensin II -> increased aldosterone

Question 19

How do α1 blockers reduce BP?3

Answer 19

1. α1 receptors cause vasoconstriction in vascular smooth muscle
2. Inhibition results in vasodilation
3. Decreased SVR -> decreased BP

Question 20

Give 2 examples of α1 blockers

Answer 20

1. Doxazosin

2. Prazosin

Question 21

Hoe do selective β blockers decrease BP?

Answer 21

1. β1 receptors in the heart stimulate an increase in heart rate and increase strength of contraction
2. β1 antagonists would result in decreased CO
3. Decreased CO -> BP

Question 22

Give 2 examples of selective β blockers

Answer 22

1. Atenolol

2. Bisoprolol

Question 23

Describe how non selective β blockers decrease BP 2

Answer 23

1. Antagonize both β and α receptors

2. Therefore, decrease CO (β) and SVR (kidneys β1; VSM α1)

Question 24

Name a non-selective β adrenoceptor antagonist

Answer 24

Propanolol

Question 25

Name a non selective α & β blocker

Answer 25

Carvedilol

Question 26

Name an α2 adrenoceptor agonist

Answer 26

Methyldopa

Question 27

What is the MOA of methyldopa? 4

Answer 27

1. Methyldopa is converted into methyl epinephrine 2. Methylepinephrine stimulates α2 receptors in the medulla 3. Result in decreased sympathetic outflow decreased SVR 4. Decreased CO and SVR decreases BP

Question 28

What are the 2 classes of calcium channel blockers?

Answer 28

1. Dihydropyridines | 2. Non-dihydropyridines

Question 29

What do dihydropyridine calcium channel blocks inhibit?

Answer 29

L type calcium channels

Question 30

Discuss how dihydropyridines work 4

Answer 30

1. L type caclium channels allow calcium to enter the cell 2. When calcium enters the cell, muscle contracts causing vasoconstriction-> increasedSVR 3. Dihydropyridines selectively block calcium channels on VSM 4. Blocking the channel results in vasodilation-> decreasing BP

Question 31

Name 2 dihydropyridines

Answer 31

1. Amlodipine | 2. Nifedipine

Question 32

What are the side effects of dihydropyridines? 5

Answer 32

All side effects are related to systemic vasodilation and include: 1. Dizziness 2. Headaches 3. Flushing 4. Peripheral oedema 5. Swelling of gums (gingival hyperplasia)

Question 33

How do non-dihydropyridines work 5

Answer 33

1. No dihydropyridines are non-selective calcium channel blockers 2. Block calcium channels in VSM and cardiac cells 3. Decreased AV node and SA node 4. Decreased contractility, HR and conduction 5. Anti-arrhythmic properties

Question 34

List 2 non-dihydropyridines

Answer 34

1. Dilitiazem | 2. Verapamil

Question 35

What are the side effects of non-dihydropyridines

Answer 35

1. Excessive bradycardia 2. Cardiac conduction abnormalities 3. Verapimil can inhibit the calcium channels in the gut leading to constipation

Question 36

Describe the 3 classes of diuretics

Answer 36

1. Loop diuretics 2. Thiazide diuretics 3. Potassium sparing diuretics

Question 37

Explain loop diuretics

Answer 37

1. Reduces the reabsorption of sodium chloride in the kidneys 2. Increased diuresis 3. Decreased volume is the vascular system results in decreased volume returning to the heart 4. Decreased BP -> decreased CO

Question 38

Give an example of a loop diuretic

Answer 38

Furosemide

Question 39

Explain how thiazide diuretics work 3

Answer 39

1. Reduce sodium reabsorption in the kidneys to a lesser extent than loop diuretics. Decreased sodium reabsorption-> increased diuresis -> decreased CO. Short term effect 2. Long term effects are thought to be produced by thiazide induced vasodilation

Question 40

Give an example of thiazide diuretics 1

Answer 40

Hydrochlorothiazide

Question 41

Explain how potassium sparing diuretics work

Answer 41

1. Interrupts the actions of aldosterone (Na reabsorption and K excretion) 2. Used in conjunction with loop or thiazide diuretics

Question 42

What do ACE inhibitors do? 3

Answer 42

1. Angiotensin converting enzyme converts angiotensin I into its active form angiotensin II 2. Inhibition of ACE results in decreased angiotensin II 3. ACE inhibitors up-regulate bradykinin -> vasodilation

Question 43

Name 2 ACE inibitors

Answer 43

1. Captopril | 2. Ramipril

Question 44

How do angiotensin receptors blockers function? 2

Answer 44

1. Angiotensin II binds to angiotensin type I receptors (AT1) which results in vasoconstriction and activation of aldosterone release 2. ARBs antagonistically bind to AT1 resulting in vasodilation and inhibition of aldosterone release

Question 45

List 2 ARBs

Answer 45

1. Losartan | 2. Valsartan

Question 46

List side effects of ACE inhibitors and ARBs

Answer 46

1. Inhibition of aldosterone-> hyperkalaemia 2. Dry couch 3. Angiooedema (increased levels of bradykinin and substance P)