Cardiovascular drugs Flashcards
MOA antiplatelet drugs
aspirin irreversibly acetylates COX preventing formation of thromboxane A2 thus inhibiting platelet aggregation
when is aspirin used
in low dose (75 mg/24h) for secondary prevention following MI, TIA/stroke and patients with angina, peripheral vascular disease. sometimes primary
which drugs cause less gastric irritation aspirin (antiplatelet) or clopidogrel etc (ADP receptor antagonists)
clopidogrel
examples of ADP receptor antagonists
(antiplatelets)- clopidogrel, prasugrel- block platelet aggregation. used if intolerant to aspirin
what role do glycoprotein IIB/IIIa antagonists have
unstable angina/ MI
example glycoprotein IIb/IIIa
tirofiban
which anticoag is used in AF and name another instance where used
warfarin; in those patients with mechanical valves
what are the newer oral agents
Xa inhibitors- apixaban; direct thrombin inhibitors- dabigatran. don’t need therapeutic monitoring
when is LMWH used
in ACS
what are alternative anticoags (not newer therapies)
parenteral fondaparinux (Xa inhibitor) or bivalirudin (thrombin inhibitor)
MOA b blockers
blocks adrenaline and NA on B adrenoceptors thus antagonising sympathetic nervous system
what does b1 receptor blockers cause in inotropic and chronotropic of heart
decreases inotropic and chronotropic - pulse decreases due to the decreased firing of SA node.
what does b2 receptor blockers induce
peripheral vasoconstriction and bronchioconstriction
what is the action of b1 receptor
incr chronotropic effect (rate), incr ionotropic effect (strength contractibility), increase renin secretion, increase ghrelin secretion(stomach)
what is the action of b2 receptor
smooth muscle relaxation, dilation of arteries to skeletal muscle, relaxation bronchioles, inhibit histamine secretion etc
what is an adrenergic receptor
GPCR receptors activated by adrenaline and noradrenaline
B blockers vary in their selectivity true or false
true
is propranolol selective
no
is bisoprolol selective
relatively B1 selective
uses of B blockers
angina, hypertension, antidysrhythmic, post MI, heart failure
contraindications of b blockers
asthma, COPD, heart block
caution use of B blockers, which can be used
heart failure. carvediol (and bisoprolol) can be used
side effects of B blockers
lethargy, erectile dysfunction, nightmares, headache
which type of diuretic is used in heart failure give example and MOA
loop diuretic- inhibits Na/2Cl/K co transporter eg furosemide
what type of diuretic is used in hypertension give example and MOA
thiazide, inhibit Na/Cl cotransporter. bendroflumethiazide
side effects of loop diuretics
dehydration, decr K, decr Ca, ototoxic
side effects of thiazides
decr K, incr Ca, decr Mg, incr urate (+- gout), impotence
example of K sparing diuretic
amiloride, spironolactone
side effect amiloride
incr K, GI upset
what are vasodilators used in
heart failure, IHD, hypertension
examples of vasodilators
nitrates, prazosin, hydralazine
MOA of nitrates
DECREASE PRE LOAD. dilates veins and large arteries so decreasing filling pressure
MOA of hydralazine
DECREASE AFTER LOAD. primarily dilates resistance vessels (used with nitrates), and decr BP
MOA prazosin
alpha blocker. dilates arteries and veins
MOA calcium channel blockers
reduce entry Ca2+- voltage sensitive channels in smooth muscle. this leads to coronary and peripheral vasodilatation, reducing coronary oxygen consumption
what receptors do the calcium channel blockers work on
L type Ca2+ channels
examples of dihydropyridines (Ca2+) and what is their principle action
nifedipine, amlodipine. peripheral vasodilators also dilate coronary arteries.
what do dihydropyridines cause and what are they used alongside, and what for
reflex tachycardia used alongside B blockers. angina and hypertension
examples of non dihydropyridines (ca2+) and action, what used for
verapamil, diltiazem. slow conduction at AV and SA. hyptertension, angina, dysrhythmias
what must you not give with B blockers
verapamil- risk severe bradycardia and LVF
side effects Ca channel blockers
flushes, headache, oedema, LV function decr, gingival hypertrophy
contraindications of Ca blockers
heart block
MOA digoxin
blocks Na/K pump. slows pulse in fast AF. weak+ve inotrope
who are at risk of incr toxicity with digoxin
elderly, use lower doses
side effects digoxin
any arrhythmia, nausea, decr appetite, yellow vision, confusion, gynaecomastia
in digoxin toxicity what needs to be checked
K+, treat arrhythmias, consider DigiFab by IVI
contraindications of use of digoxin
HCM (hypertrophic obstructive cardiomyopathy), WPW
what are dihydropyridines eg nifedipine used for
hypertension and angina
what are phenylalkalines eg verapamil used for
arrhythmias and angina
what are benzothiapenes eg diltiazem used for
hypertension, angina, arrhythmias
what is the basic MOA of a diuretic
traps ions in urine so H2O moves from blood into urine in osmotic shift
where does furosemide act
thick ascending loop of henle
where does bendroflumethiazide act
distal convoluted tubule
where does spironolactone act
collecting tubule
what can lead to decreased therapeutic index for drugs such as digoxin and amiodarone
hypokalaemia
how do K sparing diuretics work
usually Na is trapped in the loop or DCT which leads to a high conc of Na and so enhances K loss. in K sparing, the Na reabsorption is blocked in the collecting duct uncoupling the membrane which usually works in K secretion thus blocking the secretion of K into the urine
what receptor is responsible for Ca2+ release from sarcoplasmic reticulum in cardiomyocytes
ryanodine receptor
what enzyme is inhibited by statins
HMG-CoA reductase. de novo synthesis of cholesterol in the liver increasing LDL receptor expression by hepatocytes leading to decr circulating LDL cholesterol
side effects statin
muscle aches, abdo discomfort, incr transaminases
