PHARM - Drugs for the Treatment of Ischaemic Heart Disease - Week 5

Question 1

What are ischaemic heart diseases typically a result of?

Answer 1

Plaque buildup in the coronary arteries, narrowing them and preventing adequate blood flow to the heart, resulting in ischaemia.

Question 2

What is the principal artery supplying blood to the heart?

Answer 2

Coronary arteries.

Question 3

In what two ways can blood flow to the heart be increased, and why do they increase flow?

Answer 3

Dilating coronary arteries - self explanatory
Decreasing heart rate - arteries are less compressed

Question 4

What does the O2 demand of the heart depend on?

Answer 4

The cardiac workload

Question 5

Give the formula for cardiac output.

Answer 5

Stroke volume x heart rate

Question 6

Define preload.

Answer 6

Degree of stretch pre-contraction

Question 7

Define afterload.

Answer 7

Resistance the heart pumps against

Question 8

Define angina.

Answer 8

Chest pain

Question 9

Does ischaemic heart disease cause angina?

Answer 9

Yes

Question 10

Name three possible causes of angina.

Answer 10

Imbalance between O2 supply and needs
Insufficient O2 to meet cardiac demand
Reduced perfusion rather than inadequate blood O2

Question 11

Define stable angina, the pain it causes, two means by which it can be induced, and what it is associated with.

Answer 11

Chest pain that occurs with exertion or stress. It is associated with coronary artery disease.

Question 12

Define variant angina, when it occurs, and its mediator.

Answer 12

Coronary vasospasm at rest, mediator unknown.

Question 13

Define unstable angina, when it occurs (2), and what secondary complication it has the potential to cause.

Answer 13

Angina at rest and with effort.
Potential for thrombi formation.

Question 14

Do arterioles typically get plaque buildup?

Answer 14

No

Question 15

Consider stable angina treatment. What three things should treatment accomplish and what 2 effects should drugs have?

Answer 15

Treat to:
-prevent attacks
-relieve symptoms
-prevent progression to heart attack
Use drugs to:
-increase O2 supply
-reduce O2 demand

Question 16

In what two ways can O2 supply be increased?

Answer 16

Dilating coronary arteries
Reducing heart rate

Question 17

Is it relatively easy or difficult to dilate atheromatous arteries?

Answer 17

Difficult

Question 18

Can coronary arteries always be dilated?

Answer 18

Not neccessarily, they may already be maximally dilated.

Question 19

Explain why reducing heart rate increases O2 supply t othe heart.

Answer 19

Heart spends longer in relaxation phase
Coronary arteries have longer to fill

Question 20

In what three ways can O2 demand be decreased?

Answer 20

Decrease cardiac output
Reduce preload
Reduce afterload

Question 21

In what two ways can cardiac output be decreased?

Answer 21

Reduce heart rate
Reduce stroke volume

Question 22

In what two ways can preload be decreased? Give an example of a drug class for this.

Answer 22

Dilate veins
Reduce venous return
Nitrates

Question 23

In what two ways can afterload be decreased? Give an example of a drug class for this.

Answer 23

Dilate arterioles
Decrease resistance
Ca2+ channel blockers

Question 24

How do nitrates work to treat angina?

Answer 24

They are biotransformed to NO, which dilates all vessels.

Question 25

Describe the effect of NO on the following vessels (other than it dilates them) and whether it is major or minor: Veins Large arteries Coronary arteries

Answer 25

Veins -decreases preload (major) Large arteries -decreases afterload (minor) Coronary arteries -no effect

Question 26

Consider nitrates for treating angina. Name two additional effects it has on other smooth muscle, and whether they are clinically significant.

Answer 26

Other smooth muscle - brief relaxation of the gut and airways. Not clinically significant.

Question 27

Name an effect nitrates can have on blood pressure, and why this occurs.

Answer 27

Postural hypotension due to venous pooling

Question 28

Name 5 side effects of using nitrates for angina.

Answer 28

Headache Flushing -due to cerebral, head, and neck arterial dilation Reflex tachycardia

Question 29

What are nitrates typically used in combination with and to minimise what side effect?

Answer 29

B-blockers or cardiac-selective calcium channel blockers to minimise tachycardia.

Question 30

Describe four ways in which tolerance to nitrates can occur with continuous use. Name which of the four is the classic mechanism.

Answer 30

-The classic mechanism involves depletion of tissue thoils needed for NO production -Increased release/sensitivity to constrictors like AII -Increased endothelial free radical production scavenging NO, reducing bioavailability -Reduced/abnormal activity of muscle mitochondria, reducing NO production, increasing free radicals

Question 31

How can the classic mechanism of nitrate tolerance be treated? What is required for nitrate tolerance in general?

Answer 31

Treatment with N-acetyl cysteine restores GTN (glycerine) effect. A drug-free period is required to minimise tolerance - removing the patch overnight.

Question 32

Name 2 main ways B-blockers can be used to treat angina.

Answer 32

They reduce heart contractility and decrease heart rate.

Question 33

What is the first-line therapy for angina prophylaxis

Answer 33

Selective or non-selective B-blockers

Question 34

Name 6 adverse effects and contraindications for B-blockers.

Answer 34

Cold extremities Fatigue Cardiac depression Bradycardia Broncoconstriction Decreased symptoms of hypoglycaemia

Question 35

What kind of calcium channel blockers can be used for angina treatment?

Answer 35

L-type

Question 36

What four effects do calcium channel blockers have on the heart with angina treatment?

Answer 36

Decreased heart rate, stroke volume, cardiac output, and decreased O2 demand.

Question 37

What two vascular effects do calcium channel blockers have with angina treatment?

Answer 37

Arterial dilation, reducing afterload and demand

Question 38

What two drugs must calcium channel blockers never be taken with?

Answer 38

A B-blocker or digoxin

Question 39

What is the effect of ivabradine, and how does it work?

Answer 39

Pure heart rate reduction Specific and selective inhibition of inward sodium/potassium current in the sinus node

Question 40

When is ivabradine given for angina treatment?

Answer 40

Only if heart rate is >70 beats per minute

Question 41

Name 3 adverse effects of ivabradine.

Answer 41

Brightness in visual field due to retinal effects (same target, different site) Bradycardia Conduction abnormalities

Question 42

Name two factors that require precaution when giving ivabradine.

Answer 42

Heart rate <70 bpm Levels are increased by some antibiotics and antifungals

Question 43

Consider angina therapy. Are the drugs used for treatment disease-modifying? Do they lower the risk of infarction or cardiac arrest?

Answer 43

They are not disease-modifying, so there is an unchanged risk to heart disease.

Question 44

Are single drugs given for angina treatment is it a combination therapy?

Answer 44

Combination therapy

Question 45

Summarise angina therapy by lising the following drugs by whether or not they effect the following factors: Drugs -ivabradine -B-blockers -Ca2+ channel blockers -nitrates Factors -heart rate -stroke volume -afterload -preload

Answer 45

Ivabradine -lower heart rate B-blocker -lower heart rate -lower stroke volume Ca2+ channel blocker -lower heart rate -lower stroke volume -lower afterload Nitrates -lower preload

Question 46

What effect do the following factors (if decreased) have on O2 supply and demand (2): Heart rate Stroke volume Afterload Preload

Answer 46

They all decrease O2 demand Decreasing heart rate increases O2 supply

Question 47

How can a coronary spasm be treated?

Answer 47

Short-acting nitrate

Question 48

Aside from nitrates, list another drug that can be used to treat variant angina.

Answer 48

Ca2+ channel blocker

Question 49

Can B-blockers be used for treating variant angina?

Answer 49

No, they are contraindicated

Question 50

How can unstable angina be treated? What additional drug is required and why?

Answer 50

Same as for classic angina, with the addition of aspirin to prevent thrombosis.

Question 51

Name 6 ways the risk factor for angina can be reduced.

Answer 51

Stop smoking Increase physical activity Lose weight Treat hypertension, dyslipidaemia, and diabetes

Question 52

Name two revascularisation techniques for angina.

Answer 52

Percutaneous coronary intervention Coronary artery bypass graft