Drugs for ischemic heart disease

Question 1

What is angina

Answer 1

Angina pectoralis is when the supply of coronary blood and oxygen is insufficient to meed the demands of the myocardium
Presents clinically as crushing chest pain, especially on exertion

Question 2

Types of angina

Answer 2

1. Stable artherosclerotic angina : plaque formation that occludes the lumen
2. Vasospastic angina (in women for no apparent reason)
3. unstable angina: prone to rupture and thrombus formation

Question 3

What are the classes of drugs used to treat angina

Answer 3

Demand:

1. Contractility- Calcium channel blockers, beta blockers
2. Heart rate- beta blockers

Supply:

1. Vasodilators- nitrates, glyceryltrinitrate
2. Atherosclerosis drugs: Lipid lowering (statin) + post ami antithrombotic drugs (aspirin and clopidogrel)

Question 4

Name the shortterm vasodilator and the route of admin

Answer 4

glyceryl trinitrate, administer sublingually (rapid onset ,1 hr half life), or transdermal patch (longer half life)

Question 5

What is the mechanism of action of vasodilators

Answer 5

Glycerol trinitrate reduced by GSH will release nitric oxide.
Nitric oxide increases activity of guanylyl cyclase
This causes cGMP which causes inactivation of myosin light chain
MLC is then relaxed
Venodilation, arteriodilation–> decreased blood pressure (preload and after load) reduction in demands of myocardium

Question 6

What are the adverse effects of vasodilators

Answer 6

1. reflex tachy due to drop in bp
2. hypotension due to venodilation
3. meningeal artery dilation causing headaches

Question 7

What are vasodilators usually combined with and why

Answer 7

CCB or BB because they cause opposing effects, especially with regards to reflex tachycardia by depressing cardiac function

Question 8

What is the MOA of beta blockers

Answer 8

Beta blockers, stop adenylyl cyclase –> less cAMP–> less PKA–> less CICR

Question 9

What is the MOA of calcium channel blockers

Answer 9

DHP: nifedipine
Block calcium channels of the heart myocardium and smooth muscle, less CICR, less contractility and tone
reduced bp , reduce contractility : for hypertension and angina

non-DHP: verapamil, diltiazem
Block SA node AV node, prevent rentry supraventricular tachy
- anti-arrhythmic effects

Question 10

What are differences between the DHP and non DHP CCBs

1. Cardiac depressant
2. Blood pressure lowering
3. vasodilator activity

Answer 10

1. Cardiac depressant: Verapamil> diltiazem>nifedipine
2. BP lowering all equal
3. Vasodilator activity: nifedipine>diltiazem > verapamil

Question 11

Adverse effects of CCB

Answer 11

Bradycardia, AV heart block, worsen heart failure

Question 12

Why is GTN not used LT

Answer 12

tolerance, receptors sensitised and subsequently effect is not as trong