Antianginals

Question 1

T/F During the cardiac cycle, the major blood flow to the heart itself occurs during diastole.

Answer 1

TRUE

Question 2

What are the 2 major determinates of coronary blood flow?

Answer 2

(1) Oxygen demand

(2) Oxygen supply

Question 3

What are the 3 components associated with Oxygen demand?

Answer 3

(1) Heart Rate
(2) Contractility
(3) Preload, Afterload

Question 4

What are the 4 components of Oxygen supply?

Answer 4

(1) Coronary patency
(2) Diastolic BP
(3) Blood O2 capacity
(4) Collateral circulation

Question 5

T/F When there is an increase in O2 demand, there is sufficient O2 supply in the body to meet it.

Answer 5

FALSE; The demand outweighs the supply (O2 demand > O2 supply)

Question 6

What are the 3 types of Angina Pectoris?

Answer 6

(1) Typical (stable)
(2) Varient (Prinzmetals)
(3) Atypical (unstable)

Question 7

What happens during stable angina pectoris?

Answer 7

(1) Fixed atherosclerotic narrowing- fixed, stable buildup in the artery
(2) Heavy substernal discomfort
(3) Nitroglycerin

Question 8

What happens during varient angina pectoris?

Answer 8

(1) Coronary vasospasm

(2) Discomfort at rest

Question 9

what happens during unstable angina pectoris?

Answer 9

(1) Atherosclerotic plaque rupture, thrombosis

(2) Discomfort with stress or rest

Question 10

What are the 3 Nitrates?

Answer 10

(1) Nitroglycerin
(2) Isosorbide mono
(3) Isosorbide dinitrate

Question 11

What do nitrates do?

Answer 11

Smooth muscle dilator (veins > arterioles)

(1) Selective venodilator: decrease venous return (preload)= decreased ED pressure, volume= decreased tension and decrease O2 demand
(2) Small decrease in PR: decreases afterload= decreased O2 demand
(3) Coronary dilation: increase total blood flow and increase O2 supply

Question 12

What dose do you give when giving nitrates? Why?

Answer 12

A small to moderate dose; it will become a selective venodilator if you use low doses and if you use a high dose you will significantly decrease the PR which will stimulate a reflex tachycardia (which will increase O2 demand)

Question 13

Is coronary dilation transitory? What does that mean?

Answer 13

Yes; it means that the coronary dilation only lasts for a minute or two and then slowly goes back to how it was previously before the drug was administered.

Question 14

What is the major antianginal effect of nitrates?

Answer 14

The decrease in venous return (i.e. the decrease of preload to the heart)

Question 15

What is Nitroglycerin’s mechanism of action?

Answer 15

It is a nitric oxide donor that stimulates more production of NO that in turn leads to relaxation in the smooth muscle cell.

Question 16

When are nitrates used?

Answer 16

Acute stable

and variant angina

Question 17

How is NG taken? What is it for?

Answer 17

(1) Sublingual- stopping an acute attack
(2) Ointments (prophylaxis)
(3) Transdermal- (prophylaxis) reduce frequency and severity of attacks

Question 18

Why can’t NG be taken orally?

Answer 18

It has 100% first-pass metabolism

Question 19

How is Isosorb mono-dinitrate taken? What is it for?

Answer 19

Orally; for prophylaxis: reduces frequency and severity of attacks

Question 20

What are the limitations of nitrates?

Answer 20

(1) They will produce a tolerance: chronic exposure will lead to loss of effectiveness- need a 8-12 hr free period every 24 hours to combat this
(2) headache, hypotension, tachycardia (with high doses)

Question 21

What are the beta blockers?

Answer 21

Propranolol, Metoprolol

Question 22

What do beta blockers do?

Answer 22

(1) Reduces cardiac sympathetic effects: decrease HR, contractility, which decreases O2 demand

Question 23

When are beta blockers used?

Answer 23

Prophylaxis which decreases the severity and frequency of stable angina

Question 24

Why are beta blockers not used for variant angina?

Answer 24

because they are not very active against it; in variant angina you have coronary vasospasm and if you use a non-selective beta blocker you are going to block the dilating receptors which can potentially make the angina worse

Question 25

What do beta blockers do when taken post MI?

Answer 25

reduces mortality; you have increased sympathetic drive to the heart post MI leading to an increased risk of ventricular arrhythmias. The beta blocker will reduce the propensity of getting another MI.

Question 26

What are the adverse effects of beta blockers?

Answer 26

(1) cardiac suppression
(2) Rebound effect: if you give a beta blocker chronically and then take them off, you have to lower the dose little by little for the beta receptors will go back to normal (receptors are increased with chronic use)

Question 27

What are the precautions of beta blockers?

Answer 27

(1) Asthma
(2) Diabetes
(3) Heart failure
(4) Peripheral vascular disease

Question 28

What are the calcium channel blockers?

Answer 28

Verapamil, Diltiazem, Nifedipine

Question 29

What do calcium channel blockers do?

Answer 29

• Blocks Ca entry into cells (L-type Ca channels)
  (1) Smooth muscle: N>V>D: decreases afterload which decreases O2 demand; decreases coronary resistance which increases O2 supply
  (2) Cardiac muscle: V>D»N (little effect);
  
  • V,D: decrease HR, contractility, and decrease O2 demand
  • N: reflex tachycardia

Question 30

Why does Nifedipine produce a reflex tachycardia?

Answer 30

it does not effect Ca channels in the heart, just the smooth muscle so that if you vasodilate too much you’re going to have a baroreceptor sympathetic reflex tachycardia.

Question 31

What are the uses of Ca channel blockers?

Answer 31

Mostly for variant angina, also for stable anging (used as prophylaxis)

Question 32

What are the limitations of Ca channel blockers?

Answer 32

• V/D: hypotension, bradycardia, decrease CO

- N: hypotension, tachycardia

Question 33

What are the antiangina combinations?

Answer 33

(1) Nitrates and beta blocker
- decrease O2 demand and blunts reflex tachycardia
(2) Nitrates and Ca-blocker (V/D)
- V/D: decrease O2 demand and increase O2 supply
(3) Beta blocker and Ca blocker (N)
- N: blunts reflex tachycardia

Question 34

Why would you be in caution to combine nitrates and Nifedipine? Beta blocker and V/D?

Answer 34

(1) because you can get hypotension which will lead to a reflex tachycardia (neither drug work in the heart)
(2) because if you put 2 drugs that will blunt reflex tachycardia you have potential for enhanced cardiac suppression (both the drugs work in the heart)