cardiac part 2 Flashcards
what are some examples for angiotensin receptor blockers
losartna, candesartan, irbesartan - sartan
MOA for angiotensin receptor blockers
similar effects to ACEi but ARBs blocks the action of angiontensin II on the AT1 receptor
blocking angiotensin II will reduce the stimulation of aldersterone from the kidney - reducer peripheral resistance and hence lower BP (afterload) as well as vasodilation
reducing aldersterone - reduces venous return by reducing sodium and water retention (preload)
also dilates the efferent glomerular arteriole which reduces intra-glomerular pressure and slows the progression of CKD
indication of ARBs
generally used when ACEi are not tolerated due to cough
HTN - 1st or 2nd line treatment of HTN, to reduce the risk of stroke etc
chronic hear failure - 1st line treatment of all grade
ischaemic heart disease - reduce risk of subsequent cardiovascular events such as MI
Diabetic nephropathy and CKD
contra-indication for ARB
renal artery stenosis or AKI
pregnant women and breast feeding
lower dose should be used when CKD
side effect of ARB
hypotension (esp first dose)
hyperkalaemia
renal failure
interaction of ARB
other drugs which elevate potassium eg potassium sparing diuretics, aldersterone
combination of NSAIDs with ARB inc the risk of renal failure
with other diuretics, risk of profound first dose hypotension
what are some examples of nitrates?
isosorbide monoitrate, glyceryl trinitrate - nitirate
MOA for nitrates
nitrates are converted to nitric acid (NO)
NO inc cyclic guanosine monophosphate synthesis and reduces intracellular Ca2+ in vascular smooth muscles cells causing them to relax results in venous and atrial vasodilation
relaxation of venous capacitance vessels - reduce preload and left ventricular filling - reduce cardiac work and myocardial oxygen demand - relieving angina and cardiac failure
can also relieve coronary vasospasm and dilate collateral vessels - improving coronary perfusion
also relax the systemic arteries, reducing peripheral resistance and afterload
indication for nitrates
short-acting nitrate (glyceryl trinitrate) used in treatment of acute angina and chest pain associated with acute coronary syndrome
long-acting nitrate - prophylaxis of angina where a beta-blocker and/or a CCB are insufficient or not tolerated
IV nitrates are used in the treatment of pulmonary oedema usually in combination with furosemide and oxygen
contra-indication for nitrate
should not use in pt with severe aortic stenosis where cardiovascular collapse can happen - the heart is unable to inc cardiac output sufficiently through the narrow valve area to maintain pressure in the now dilated vasculature
should be avoid in those who are haemodynamically instable esp hypotension
side effect of nitrate
flushing, headaches, light-headedness and hypotension
tolerance with reduced symtpoms relief
interaction of nitrate
must not be used with phosphodiesterase inhibitors eg sildenafil - enhance and prolong the hypotensive effect of nitrates
caution with those taking antihypertensive medication
where is nitrate eliminated
liver, RBC and vessel walls
what is the drug class for digoxin
antidysrrhythmia
what is the MOA for digoxin
it is -ve chronotropic (reduced HR) and +ve iontropic (inc force of contraction)
it works indirectly in the situation of AF and flutter as it act through the vagal tone (parasympathetic) - reduced the conduction in AV node preventing some impulses from being transmitted to the ventricles - lowering ventricular rate
in HF - direct effect on myocytes by inhibiting the NA+/K- -ATPase pump - inc intra-cellular NA+ conc - inc contractile force
indication for digoxin
AF and atrial flutter - reduces the ventricular rate - beta-blocker or non-dihydropyridine CCB is more effective
severe HF - 3rd line treatment for patietns who are already taking ACEi, beta-blocker and either an aldosterone antagonist or AT1 blocker
contra-indication for digoxin
worsen conduction abnor - 2 degree heart block and intermittent complete heart block
no use in pt at risk of ventricular arrhythmia
should reduce in kidney failure
hypokalaemia, hypomagnesaemia and hypercalcamia can inc digoxin conc
side effect of digoxin
bradycardia
GI upset
rash
dizziness
visual disturbance (blur or yellow vision
needs to be aware of digoxin as it has a low therapeutic index