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
interaction of digoxin
loop and thiazide diuretics - hypokalaemia
amidorone, CCB, spironolactone and quinine - all inc plasma conc of digoxin and risk of toxicity
what sort of drug is Amiodarone
Anti-dysarrhythmia
MOA for Amiodarone
block - NA+, K- and Ca2+ channel in cardiomyocytes
antagonist for alpha and beta adrenergic receptors
main effect in the AV node - reduce spontaneous depolarisation ( automaticity), slow conduction velocity, inc resistance to depolarisation (refractoriness) - this reduces the ventricular rate in AF and flutter
will also inc the chance of conversion to and maintenance of sinus rhythm
may break the circuit of self-perpetuating that induces the AV node and restore the sinus rhythm in SVT
indication for Amiodarone
tachyarrhythmia - AF, atrial flutter, SVT, ventricular tachycardia and refractory ventricular fibrillation
generally used when other treatments are not available
contra-indication for amiodarone
should be avoided with
- severe hypotension
- heart block
- active thyroid disease
where is digoxin eliminated
kidney
side-effect of amiodarone
can cause hypotension during IV infusion
when taken chronically - pneumonitis, bradycardia, AV block, hepatitis, photosensitivity and grey discolouration (skin)
can stimulate thyroid - contain iodine (amiodarone) - ca n cause hypo-hyperthyroidism
long half-life and take months to take out of system
interaction of amiodarone
many
inc plasma conc of digoxin, diltiaem and verpamil - inc risk of bradycardia, AV block and HF (dose should be 1/2 is used with amiodarone)
what sort of drug is aspirin
anti-platelet
MOA for aspirin
aspirine irreversibility inhibit cyclooxygenase (COX) to reduce production of pro-aggregatory factor thromboxane from arachidonic acid - reducing platelet aggregation
aspirin binds to platelet for the lifetime of platelets and will only disappear with platelet dies
indication for aspirin
treatment for ACS and acute ischaemic stroke
long term secondary prevention of thrombotic arterial events in pt with cardiovascular, cerebrovascular adn peripheral arterial disease
reduce the risk of thrombus and embolic stroke in AF when warfarin are contra-indicative
mild-to-moderate pain and fever (other drugs preferred)
contra-indication for aspirin
should not be give to children under 16 - risk of Reye’s syndrome (rare but life threatening affect the liver and brain)
hsould be avoided in 3rd trimester of pregnancy when prostaglandin inhibition
caution with peptic ulcers and gout as it will trigger any effect
side-effect of aspirin
GI irritation GI ulceration and haemorrhage hypersensitivity reaction incl bronchospasm high dose causes - tinnitus overdose is life threatening
interaction of aspirin
inc risk of bleeding if used with other antiplatelet
What sort of drug is Clopidogrel
clopidogrel prevents platelet aggregation and reduces the risk of arterial occlusions by binding irreversibly to adenosine diphosphate (ADP) receptor on the surface of platelets
indication for clopidogrel
generally prescribed with aspirin although clopidogrel maybe used alone
1) treatment of ACS
2) prevent occlusion of coronary artery stents
3) for long-term secondary prevention of thrombus arterial events in pt with cardiovascular, cerebrovascular and peripheral arterial disease
4) reduce risk of intracardiac thrombus and and embolic stroke in AF where warfarin is contraindicated
contra-indication for clopidogrel
should not be prescribed to pt with active bleeding
needs to stop 7 days before elective surgery
should be used in caution with pt with renal and hepatic impairment
where is clopidogrel elminated in the body
liver and kidney
side effect of clopidogrel
bleeding esp GI bleed, intracranial
GI pset - dyspepsia, abdo pain and diarrhoea
might cause thrombocytopenia
interaction of clopidogrel
pro-durg and needs metabolisation of P450 cytochrome to activate it
maybe reduced by cytochrome P450 inhibitors eg omeprazole, ciprofloxacin, erythromycin, ssri
inc risk of bleeding with aspirin, anticoagulants - heparin or NSAIDs
what are some examples of heparins and fondaparinux
Enoxaparin, dalteparin, fondaparinux, unfractionated heparin
which one of the heparins and fondaparinux are low molecular weight?
enoxaparin and delteparin
MOA for heparin and fondaparinux
mainly inhibiting thrombin and factor Xa which are finally step to fibrin clot
unfractureated heparin - activates antithrombin - inactivates clotting factor Xa and thrrombin
LMWH - dalteparin & enoxaparin - also activate the antithrombin and inactivates clotting factor Xa
Fondaparinux - synthetic compound similar to heparin and inhibit factor Xa only
indication for heparin and fondaparinux
venous thromboembolism - LMWH fist choice and 1st chocie for DVT and PE
ACS - LMWH or fondaparinux part of 1st line treatment
contra-indication for heparin and fondaparinux
used with caution in pt at inc risk of bleeding incl clotting disorder, severe unctonroled hypertension or recent surgery or trauma
heparin hsould be avoid in times of invasice procedures eg LP and spinal anaesthesia
lower dose for pt with renal impairment as they can accumulate
where are heparin and fondaparinux eleminated
kidney
side-effect of heparin and fondaparinux
bleeding
injection site infection heparin-induced thrombocytopenia
interaction of heparin and fondaparinux
antithrombotic drugs combination should be avoided - inc risk of bleeding
