Drugs for Coronary (Ischaemic) Heart Disease

Question 1

What are the 3 types of angina?

Answer 1

1. Atherosclerotic/Stable angina
2. Vasospastic/Prinzmental/Rest/Variant angina
3. Unstable angina

Question 2

What are the determinants of cardiac oxygen requirement?

Answer 2

1. Preload (diastolic filling pressure - depends on blood vol. & venous tone)
2. HR
3. Afterload (TPR - determined by arterial blood pressure)
4. Cardiac contractility

Question 3

What are the 4 classes of drugs for the therapy of angina?

Answer 3

1. Vasodilators (nitrates)
2. Cardiac depressants (Ca2+ channel blockers, ß blockers)
3. Anti-platelet drugs (clopidogrel)
4. Lipid-lowering drugs (statins)

Question 4

What is the main theory behind angina therapy?

Answer 4

1. Increase blood flow

2. Decrease O2 requirement

Question 5

What is the nitrate used for angina?

Answer 5

Nitroglycerin (glyceryl trinitrate GTN)

Question 6

What is the MOA of nitrates?

Answer 6

Activates guanylyl cyclase

• Increase conversion of GTP to cGMP
• Inactivation of myosin-LC
• Vasorelaxation (venodilation decreases preload, arteriolar dilation decreases afterload)
• Decrease O2 consumption

Question 7

How are nitrates administered? What are the respective onsets and durations?

Answer 7

1. Sublingual
   Onset: 1.5min
   Duration: 10-30min
2. Transdermal
   Onset: 30-60min
   Duration: 7-10h

Question 8

There are more desirable therapeutic effects when nitrates are taken together with what other drugs?

Answer 8

Nitrates +

ß-blockers or Ca2+ channel blockers

Question 9

What are the adverse effects of nitrates?

Answer 9

As a result of vasorelaxation:
1. Baroreflex –> tachycardia

2. Venodilation –> hypotension
3. Meningeal artery vasodilation –> headache
   - Tolerance (increase dose if taken long-term)

Question 10

What is a DHP Ca2+ channel blocker?

Answer 10

Nifedipine

Question 11

What are the non-DHP Ca2+ channel blockers?

Answer 11

Verapamil

Diltiazem

Question 12

What is the MOA of non-DHP Ca2+ channel blockers?

Answer 12

Decrease intracellular Ca2+

• Block SA, AV node
• Decrease supraventricular, re-entry tachycardia

Question 13

What is the clinical use of non-DHP Ca2+ channel blockers?

Answer 13

Anti-arrhythmic

Question 14

What are the clinical uses of DHP Ca2+ channel blockers?

Answer 14

1. Anti-angina

2. Anti-hypertension

Question 15

What are the adverse effects of DHP Ca2+ channel blockers?

Answer 15

Cardiac depression:

• Bradycardia
• AV block
• HF

Question 16

In terms of lowering BP, rank the effectiveness of the Ca2+ channel blockers (both DHP and non-DHP)

Answer 16

Verapamil=Diltiazem=Nifedipine

Question 17

In terms of vasodilation, rank the effectiveness of the Ca2+ channel blockers (both DHP and non-DHP)

Answer 17

DHPs are more effective

Nifedipine>Diltiazem>Verapamil

Question 18

In terms of cardiac depression, rank the effectiveness of the Ca2+ channel blockers (both DHP and non-DHP)

Answer 18

Non-DHPs are more effective

Verapamil>Diltiazem>Nifedipine