Stable Ischaemic Heart Disease and Angina Therapy Flashcards
what are the risk factors for SIHD and angina?
> hypertension > smoking > hyperlipidaemia > hyperglyaemia > male > post-menopausal females
what is the purpose of drug treatment?
> relieve symptoms > halt disease process > regress the disease process > prevent myocardial infarction > prevent death
in an atheroma plaque what layer of artery is affected the most?
the intimal area
how does stable angina arise?
a mismatch between myocardial blood/oxygen supply and demand
how do drugs correct the supply and demand imbalance of oxygen in the myocardium?
Decrease myocardial oxygen demand: > reduction of the heart rate > reduction of the myocardial contractility > reduction of afterload Increase supply of oxygen to myocardium
name 2 beta blocker used
> bisprolol
> atenolol
what are beta blockers?
reversible antagonists for beta1 and 2 receptors
what three things do beta blockers decrease?
> heart rate
contractility
systolic wall tension
how do beta blockers improve perfusion of the sub-endocardium
by increasing diastolic perfusion time
what do beta blockers protect cardiomyocytes from during ischemic episodes?
oxygen free radicals
how do beta blocker increase the threshold at which angina occurs?
they reduce the heart rate, force of contraction and blood pressure so the balance point at which demand for oxygen outstrips the supply.
what is rebound phenomena?
sudden cessation of beta blocker therapy may precipitate myocardial infarction
what are the contraindications for beta blockers?
> asthma > peripheral vascular disease > raynauds syndrome > heart failure (dependant on sympathetic system) > bradycardia/heart block
what adverse drug reaction can occur due to beta blockers?
> tiredness > lethargy > impotence > bradycardia > bronchospasm
what drug-drug interactions with beta blockers can cause hypotension?
other hypotensive agents
what drug-drug interactions with beta blockers cause bradycardia?
other rate limiting drugs such as verapamil or diltiazem
what drug-drug interactions with beta-blocker cause cardiac failure?
negatively inotropic agents such as verapamil, diltiazem or disopyramide
what drug-drug interactions with beta blockers agonise antihypertensive actions?
NSAIDs
what are the drug drug interaction of beta-blockers and insulin/oral hypoglycaemics?
they exaggerate and mask hypoglycaemic actions of insulin or oral hypoglycaemics
name three calcium channel blocker
> diltiazem
verapamil
amlodipine
what is the action of calcium channel blockers?
they prevent calcium influx into myocytes and smooth muscle lining the arteries and arterioles by blocking the l-type calcium channels. this reduces vascular tone, afterload, heart rate and myocardial oxygen requirements.
what are the effects of rate limiting calcium channel blocker?
they reduce heart rate and force of contraction
what are the effects of vasodilating calcium channel blockers
they produce a reflex tachycardia
why should you never use nifedipine immediate release?
there is evidence that the use of rapidly acting vasodilatory CCBs may precipitate and MI or stroke