Treatment of ischemic heart disease Flashcards
What is ischemic heart disease?
A consequence of inadequate coronary perfusion relative to
myocardial demand.
What are the causes of myocardial ischemia
Pre-existing (“fixed”) atherosclerotic occlusion of the coronary
arteries
* Acute plaque change with superimposed thrombosis and/or
vasospasm
What is angina pectoris
Characteristic chest pain (burning or heavy discomfort behind the sternum), of duration <
15 minutes, due to myocardial ischaemia, usually occurring on exercise and relieved by
rest
3 steps in the tx of angina pectoris
- B-Blocker: Atenolol
- Add 2nd agent: Long acting calcium channel blocker: Amlodipine
- Add 3rd agent: Isosorbide mononitrate/dinitrate
What is the Long-term prophylaxis for thrombosis/cardiovascular events?
Aspirin, oral, 150 mg daily.
HMGCoAreductase inhibitor (statin)
Simvastatin / Rosuvastatin
Atorvastatin
Tx for relief of angina
Nitrates, short acting e.g.:
Isosorbide dinitrate, sublingual, 5 mg
Pt counselling points regarding Tx for angina relief (4)
o Maybe repeated if required at 5‐minute intervals for 3 or 4 doses.
o Instruct patients to keep the tablets in the airtight and lightproof container in
which they are supplied.
o Instruct patients that nitrates are not addictive.
o Instruct patients to use prophylactically, before activities which may provoke
angina.
List 3 organic nitrates
- Glyceryl trinitrate
- Isosorbide mononitrate
- Isosorbide dinitrate
What are the actions of nitrates?
Relax smooth muscle, especially vascular smooth muscle (also
oesophageal and biliary)
* Relax veins, reduction in central venous pressure (reduced preload)
* Reduced stroke volume = venous pooling on standing, postural hypotension and dizziness
T/F: Therapeutic doses have less effect on
small resistance arteries than on veins
but marked effect on larger muscular
arteries.
T
Effects of organic nitrates on coronary arteries
Direct dilation of coronary
arteries – increased coronary flow
effects of organic nitrates on myocardial oxygen consumption
Decreased myocardial oxygen consumption (decreased pre- & afterload)
Effects of organic nitrates on coronary sinus blood
Increased oxygenation of coronary sinus blood
Effects of organic nitrates on collateral vessels
dilation of collateral vessels
State 3 anti-anginal actions of organic nitrates
- Reduced cardiac work – reduced pre- & after load = reduced oxygen
demand - Redistribution of coronary flow to ischaemic areas via collaterals
- Relief of coronary spasm
Adverse effects of nitrates
Main adverse effects are direct consequence of pharmacological action
(type A)
* Postural hypotension and headache – tolerance to these effects
develops quickly
T/F: Glyceryl nitrate is rapidly inactivated by hepatic metabolism
T
ROA and onset of action of glyceryl trinitrate
sublingual – onset of action = few minutes
converted to di- and mononitrates
Can also be absorbed through the skin – transdermal patch
Duration of action of glyceryl trinitrate
30min
Organic nitrates are highly ____________________
so they evaporate quickly when opened.
Volatile
Which formulation of organic nitrates is more stable?
Spray
Isosorbide mononitrate pharmacokinetics, ROA and dosage instructions
Isosorbide mononitrate: longer acting, absorbed and metabolised
more slowly.
* Route of administration: oral
* Take twice daily in the morning (8:00) and at lunch (14:00) to allow
for the nitrate free period (to avoid tolerance)
Least lipophilic cardio-selective b-blocker
Atenolol - loses selectivity at high doses
Excretion and frequency of dose of atenolol
Excreted mainly unchanged in the urine – may accumulate in kidney
failure
give once daily
T/F: Atenolol is affected by liver disease, or drugs inhibiting hepatic metabolism
or conditions affecting hepatic blood flow
F. It is not affected
contraindications of atenolol (4)
Contraindicated in heart block, symptomatic heart failure (unless or
until signs are controlled), sinus bradycardia, cardiogenic shock
Cautions of atenolol 2
renal failure, pregnancy
Drug interactions with atenolol
Digoxin, verapamil, diltiazem additive depressant effects on the heart;
* Insulin/oral antidiabetics, increased risk of hyperglycaemia and masking of hypoglycaemia (except sweating)
adverse effects of atenolol
Decreased HDL, increased TGs and glucose utilization impairment, bronchospasm (asthma, high doses)
4 characteristics of unstable angina
angina at rest or minimal effort
* angina occurring for the first time, particularly if it occurs at rest
* prolonged angina > 10 minutes, not relieved by sublingual nitrates
* the pattern of angina accelerates and gets worse
5 short term Tx goals for acute coronary syndrome
Early restoration of blood flow to the infarct-related artery to prevent
infarct expansion (in the case of MI) or prevent complete occlusion and MI (in UA);
* Prevention of death and other MI complications;
* Prevention of coronary artery re-occlusion
* Relief of ischemic chest discomfort.
3 long term Tx goals for acute coronary syndrome
Control of atherosclerosis risk factors,
* Prevention of additional MACE, including reinfarction, stroke, and HF
* Improvement in quality of life.
