19. Drugs To Treat CVS

Question 1

How do beta blockers work in the CVS?

Answer 1

Competitive reversible antagonists block action of sympathetic NS. Decrease BP, HR, SV, CO

Question 2

What are the adverse effects of beta blockers?

Answer 2

Exacerbate asthma, intolerance to exercise, hypoglycaemia, vivid dreams

Question 3

How do alpha blockers work in the CVS?

Answer 3

Competitive reversible antagonists block sympathetic tone in arterioles. Decrease peripheral resistance

Question 4

What are the adverse effects of alpha blockers?

Answer 4

Postural hypertension, reflex tachycardia

Question 5

How do ACE inhibitors work?

Answer 5

Reduce formation of AT-II (vasoconstrictor) and reduce blood volume (no stimulated release of aldosterone)

Question 6

What are the adverse effects of ACE inhibitors?

Answer 6

Sudden fall in BP on first dose, persistent cough

Question 7

How do AT-II receptor blockers work?

Answer 7

Block actions of AT-II to reduce BP

Question 8

How do diuretics work?

Answer 8

Lower BP by decreasing blood volume. Reduce renal reabsorption of Na+ and water

Question 9

How do calcium channel blockers work?

Answer 9

Block L-type voltage-operated calcium channels to stop Ca2+ entry causing depolarisation + contraction. Reduce TPR and CO

Question 10

Which calcium blocker drugs are smooth muscle and cardiac muscle most sensitive to?

Answer 10

Smooth muscle: nifedipine > diltiazem > verapamil

Cardiac Muscle: opposite

Question 11

What are adverse effects of calcium blockers?

Answer 11

Headache, constipation, cardiac dysthymias, gum hyperplasia (overgrowth)

Question 12

Why does angina pectoris occur?

Answer 12

Due to myocardial ischaemia resulting in a build up of metabolites in the chest which activates sensory nerves. Causes pain
When increased myocardial O2 demands are not met

Question 13

What are the three types of angina?

Answer 13

Stable - attacks during exercise, due to occlusion in coronary artery (need cholesterol-lowering drugs)
Unstable - unpredictable attacks, occlusion due to platelet adhesion to ruptured plaque (need anti-platelet drugs)
Variant - vasospasm of coronary artery

Question 14

How is angina treated?

Answer 14

By decreasing the myocardial O2 demand with vasodilator drugs

Question 15

How do angina drugs work?

Answer 15

Block SA node depolarisation so HR decreases but not force of contraction - decreases myocardial O2 demand

Question 16

What is the Bainbridge reflex?

What does it cause?

Answer 16

A sympathetic reflex initiated by increased blood in the atria.
Causes stimulation of SA node and baroreceptors in atria -> increased sympathetic NS stimulation

Question 17

How are nitrovasodilators used?

Answer 17

To treat angina. Rapid action but short lived. Taken immediately before exercise or for relief during angina attack

Question 18

What type of dilation do nitrovasodilators cause?

Answer 18

Venous dilatation is greater than arterial.

Question 19

What are the causes of heart failure?

Answer 19

Hemodynamic overload due to excess pressure or volume
Neurohumoral overload
Tissue damage ie MI
Genetic response

Question 20

What are the symptoms of L ventricular failure?

What are the symptoms of R ventricular failure?

Answer 20

Fatigue, pulmonary oedema

Venous distension, oedema

Question 21

How is heart failure treated?

Answer 21

Try to reduce preload/afterload or make heart work harder
Use diuretics or ACE inhibitors
Also positive inotropes

Question 22

Which positive inotropes are used for heart failure?

When would they be used?

Answer 22

Dopamine and Dobutamine - make heart work harder

Used when heart failure patients have not responded to standard treatment

Question 23

What do calcium sensitisers do?

Answer 23

Increase contractility of the heart by increasing amount of calcium bound to troponin-C

Question 24

How do digitalis compounds work?

Answer 24

Increase contractility of the heart to treat heart failure by increasing intracellular calcium. Makes more calcium available to bind to troponin-C

Question 25

What is considered a “good” lipoprotein?

Answer 25

HDL, small in size. Large VLDL are bad

Question 26

How do statin drugs work?

Answer 26

Inhibit cholesterol biosynthesis to decrease cholesterol levels.