Stable angina therapy Flashcards
what are different drug therapies given for stable angina?
beta adrenoreceptor antagonist ivabradine calcium channel blockers nitrates potassium channel openrs aspirin/clopidogrel/trigagrelor statins
name 3 rate limiting drugs used to treat stable angina.
beta adrenoraceptor antagonists
Ivabradine
calcium channel blockers
name 2 vasodilator drugs used to treat stable angina.
calcium channel blockers
nitrates i.e. GTN
name 2 common beta blocker drugs used.
bisoprolol and atenolol
what is the name for beta blockers which only inhibit the b1 receptors?
cardioselective
how do beta blockers help reduce anginal symptoms?
angina is caused by lack of oxygen supply to the myocardium.
beta blockers allow improved perfusion to the sub endocardiumm by increasing diastolic perfusion time.
the heart is relaxed in diastole so the vessels are dilated this more blood flow.
beta blockers work by decreasing which 3 major determinants of myocardial oxygen demand?
heart rate
contractility
systolic wall tension
what does sudden cessation from beta blockers cause?
rebound phenomenon
describe how rebound phenomenon occurs.
sudden cessation of beta blockers can cause a drop in blood pressure and so the heart rate rapidly increases to compensate
this may precipitate a myocardial infarction
who are at risk of beta blocker rebound phenomenon?
patients with angina and men over 50 years receiving BB for other reasons
what are the contraindications for beta blockers?
asthma peripheral vascular disease raynauds syndrome heart failure bradycardi/heart block
what are the adverse reactions from beta blockers?
tiredness/fatigue lethargy impotence bradycardia bronchospasm
what can result if beta blockers are used with veramapil or diltiazem?
bradycardia
how do calcium channel blockers work?
they prevent calcium influx int myocytes and smooth muscles lining arteries and arterioles by blocking the L-type calcium channel
what are 2 rate limiting calcium channel blockers?
diltiazem and verapamil
what type of drug is nidfedipine?
calcium channel blocker
what contraindications are there for nifedipine?
nifedipine should never be used for immediate release
evidence that it may perpetuate an acute MI or stroke
name 2 vasodilating calcium channel blockers.
amlodipine and nifedipine
how does CCB’s reduce myocardial work load?
they reduce vascular tone and reduce after load
how does rate limiting CCB’s reduce myocardial oxygen requirements?
reduce the heart rate and the force of myocardial contraction
what is the action of glyceryl trinitrate?
GTN is a vasodilator.
it relaxes almost all smooth muscle by releasing NO which then stimulates the release of cGMP which produces smooth muscle relaxation.
how does nitrates reduce myocardial oxygen consumption?
by causing vasodilation from smooth muscle relaxation, nitrates reduce preload and after load which reduces oxygen consumption
how does nitrates reduce preload?
it causes peripheral vasodilation and so reduces venous return and therefore preload
what are oral nitrates used for?
prophylaxis
usually 1 tablet per day
tablets are a sustained released formulation
when is IV nitrates used and what with?
IV nitrates are used for treatment of unstable angina and are used in combination with heparin
what is one of the common problems of nitrates?
tolerance to the effects of nitrates can develop rapidly
how can tolerance of nitrate be overcome?
giving asymmetric doses of nitrate i.e. 8am then 2pm
and/or using a sustained preparation which therefore means the patient has a nitrate free period
what are the adverse drug reactions from nitrates?
headache
hypotension - GTN syncope
describe how nicorandil works .
nicorandil activates ischaemic pre-conditioning.
it activates ATP sensitive potassium channels.
the entry of potassium into cardiac myoytes inhibits calcium influx and so has a negative inotropic action - reducing heart rate
what type of drug is Ivabradine?
ivabradine is a selective sinus node If channel inhibitor
how does ivabradine reduce heart rate?
ivabradine inhibits the sinus node If channel which slows the diastolic depolarisation slop of the SA node.
what are the new drug approaches/treatments to treat ischaemia?
metabolic modulation (trimetazidine)
sinus node inhibition (ivabradine)
pre conditioning (nicorandil)
late Na current inhibition (ranolazine)
what are the indications of aspirin for CAD?
aspirin is used in adults who are unable to tolerate or have a contraindication to the use of beta blockers
or are used in combination with beta blockers in patients who are adequately controlled with optimal beta blocker use
what is the main adverse reaction from aspirin?
GI bleed
what type of drugs are HMG CoA reductase inhibitors?
statins
