Drugs

Question 1

What are the two groups of drugs used to treat heart failure?

Answer 1

Drugs that increase cardiac output

Drugs that reduce workload of the heart

Question 2

Why are drugs that increase cardiac output not often used to treat heart failure?

Answer 2

Have negative long-term effects on heart

Question 3

What are the drugs that increase cardiac output?

Answer 3

Cardiac glycosides

B1 adrenoceptor agonists

Question 4

How do cardiac glycosides work?

Answer 4

Block Na+ K+ ATPase

Increase vagal activity

Question 5

What is the effect of the Na+ K+ ATPase being blocked?

Answer 5

Increase in intracellular conc. of Na+
Decreased activity of Na+ Ca2+ exchanger, due to reduced diffusion gradient of Na+ to enter cell
Increased intracellular Ca2+ conc.
More Ca2+ stored in sarcoplasmic reticulum

Question 6

What are the effects of more Ca2+ in SR?

Answer 6

More Ca2+ released during action potentials
Higher intracellular Ca2+ conc.
Increases contractility
Positive inotropy - increased force of contraction

Question 7

What are the effects of increasing vagal activity?

Answer 7

Decrease in heart rate

Decrease in AV node conduction velocity

Question 8

When are cardiac glycosides used to treat heart failure?

Answer 8

When the patient has an arrythmia also e.g. atrial fibrillation

Question 9

What is an example of a beta adrenoceptor agonist?

Answer 9

Dobutamine

Question 10

What is dobutamine used to treat?

Answer 10

Cardiogenic shock

Acute heart failure

Question 11

What are the types of drugs that reduce workload of the heart?

Answer 11

ACE inhibitors

Beta adrenoceptor antagonists

Diuretics

Question 12

How do ACE inhibitors work?

Answer 12

Prevent action of ACE

Prevent it from converting angiotensin 1 into angiotensin 2

Question 13

How does less angiotensin 2 reduce the workload of the heart?

Answer 13

Decreased sodium and water retention
reduced blood volume
reduced preload of heart
reduced force of contraction

Decreased vasoconstriction
decreases TPR, blood pressure
reduced afterload of heart

Question 14

What can be used instead if an ACE inhibitor is not tolerated by the patient?

Answer 14

Angiotensin 2 receptor blocker

Question 15

How do diuretics work?

Answer 15

Increase excretion of water, less reabsorption
decreased blood volume
reduced preload
reduced force of contraction

Question 16

What are the two groups of drugs used to treat angina?

Answer 16

Drugs that reduce workload of heart

Drugs that increase blood supply to heart

Question 17

What are the drugs that reduce workload of the heart?

Answer 17

Beta adrenoceptor antagonists

Ca2+ channel blockers

Organic nitrates

Question 18

What are the drugs that increase blood supply to heart?

Answer 18

Organic nitrates

Ca2+ channel blockers

Question 19

What type of cell do organic nitrates act on?

Answer 19

Vascular smooth muscle cells

Question 20

What do organic nitrates react with in smooth muscle cells? What does this release?

Answer 20

Thiol -SH groups

Releases NO2-, reduced to NO

Question 21

What are some examples of nitric oxides?

Answer 21

Glyceryl trinitrate (GTN)

Isosorbide dinitrate

Question 22

What is the effect of NO?

Answer 22

Vasodilation

Question 23

How does NO cause vasodilation?

Answer 23

Activates guanylate cyclase
converts GTP into cGMP
cGMP activates PKG
PKG decreases intracellular Ca2+ conc.
causes relaxation of smooth muscle cell

Question 24

What type of blood vessels do organic nitrates mostly act on?

Answer 24

Veins - venodilation

Collateral coronary arteries

Question 25

How does venodilation reduce workload of the heart?

Answer 25

Lowers venous pressure reduced preload of heart reduced force of contraction

Question 26

How does collateral coronary artery dilation increase blood supply to heart?

Answer 26

Collateral coronary arteries bypass blockage in coronary artery increased blood flow through bypass to ischaemic area

Question 27

How significant is collateral coronary artery dilation in increasing blood supply to heart?

Answer 27

Not very significant | because there aren't many end arteries

Question 28

When might collateral coronary arteries develop?

Answer 28

With myocardial ischaemia in order to increase blood supply to the area by bypassing the blocked coronary artery

Question 29

Why do organic nitrates mostly act on the veins?

Answer 29

Because there is less endogenous nitric oxide in veins | so it has a greater effect in the veins

Question 30

Which heart conditions carry an increased risk of thrombus formation?

Answer 30

Atrial fibrillation Acute MI Prosthetic heart valves

Question 31

Why does atrial fibrillation carry an increased risk of thrombus formation?

Answer 31

Atria not contracting properly | Blood becomes stagnant, pools

Question 32

Where in the atria do thrombi tend to form?

Answer 32

Auricles

Question 33

What are the types of antithrombotic drugs? How are they different?

Answer 33

Anticoagulant drugs - prevent blood clot formation Antiplatelet drugs

Question 34

What are the different anticoagulant drugs?

Answer 34

Heparin Fractionated heparin Warfarin

Question 35

How is heparin given?

Answer 35

IV

Question 36

How does heparin work?

Answer 36

Inhibits thrombin

Question 37

How is fractionated heparin given?

Answer 37

Subcutaneous injection

Question 38

How is warfarin given?

Answer 38

Orally

Question 39

How does warfarin work?

Answer 39

Antagonises action of Vit. K

Question 40

What is an example of an antiplatelet drug?

Answer 40

Aspirin

Question 41

When is aspirin used?

Answer 41

Following acute MI Or if have high risk of MI

Question 42

When timeframe is heparin used for?

Answer 42

For short-term action

Question 43

What timeframe is fractionated heparin used for?

Answer 43

For more long-term action

Question 44

What are the different groups of drugs used to treat hypertension?

Answer 44

ACE inhibitors Ca2+ channel blockers Diuretic Beta blockers A1 adrenoceptor antagonists

Question 45

How do Ca2+ channel blockers treat hypertension?

Answer 45

Cause relaxation of smooth muscle in blood vessels so vasodilation decreases TPR, blood pressure

Question 46

How do diuretics treat hypertension?

Answer 46

Decrease water retention reduce blood volume reduced preload, SV, CO reduce blood pressure

Question 47

How do beta blockers treat hypertension?

Answer 47

Reduce heart rate reduce force of contraction, SV reduce CO, blood pressure

Question 48

How do A1 adrenoceptor antagonists treat hypertension?

Answer 48

Prevent vasoconstriction of smooth muscle in blood vessels giving vasodilation reduce TPR, blood pressure

Question 49

How do ACE inhibitors treat hypertension?

Answer 49

Prevent formation of angiotensin 2 reduced sodium, water retention reduced blood volume reduced preload, SV, CO reduced blood pressure reduced vasoconsriction, increased vasodilation reduced TPR, blood pressure