Vasodilators in Angina Flashcards
Physiology of Angina
imbalance btwn O2 supply and O2 demand
Stable angina
supply O2 constant
incr O2 demand
Unstable angina
major decr O2 supply due to thrombosis
incr O2 demand
Variant angina (not due to atherosclerosis)
major decr O2 supply due to vasospasm
O2 demand same
major determinants of myocardial O2 consumption
1) contractile state
2) heart rate
3) myocardial wall tension (LV pressure) and stress (ventricular volume)
Two effectsors of wall tension
1) preload (LV EDP) = venous (use vasodilators)
- isosorbide dinitrate
- nitroglycerin /isosorbide mononitrate–> NO
2) afterload (high SVR SBP) - arteriole (use calcium channel blockers = arteriole selecive) and affects blood pressure
- hydralazine
which drug decreases wall tension (preload and afterload) in both vascular beds?
NIPRIDE (NITROPRUSSIDE)
decr venous capacitance and incr venous capacitance
EMERGENCY ANTI-HYPERTENSIVE because afterload affects blood pressure (SVR-SBP)
when to not use nipride
if patient is hypotensive
which drugs have an effect on coronary blood flow to incr O2 supply
CCBs (Verapamil-Dilt only)
Nitrates (Verapamil-Dilt only)
but MUCH LESS THAN CATH LAB
which drug to decr demand initially in most patients
beta blockers
- decr heart rate
- decr contractility
a
some CCBs affect HR and contractility (phase 2)
what drugs to use for stable angina
1) beta blockers
2) nitrates
3) ca channel blockers
what drugs to use for unstable angina
1) antiplatelet- anticoags
2) beta blockers
3) nitrates
4) CCBs
what drugs to use for variant angina
1) calcium channel blockers
2) nitrates
don’t use Ca2+ channels with ___
ACS
best way to incr CBP
1) surgically with CABG-PTCA
2) vasodilator drugs
best way to decr myocardial O2 demand
1) vasodilators
2) negative inotropic
3) negative chronotropic
what drug DON’T USE WITH PRINZMETAL OR VARIANT ANGINA
no beta blockers because not vasodilators
best to use CCBs
preventative drugs to use in stable angina
antiplatelet
statins
preventative drugs to use in unstable angina
antiplatelet/anticoag
antithrombotic
statins
preventative drugs to use for variant angina
NONE
preventative drug to use for MI
antiplatelet/anticoag/fibrinolytic
antithrombotic
statin
mechanism of NO
NO activate guanylate cyclase –> incr cGMP –> relax smooth muscle
primary effects of NO
1) decr LVEDP (wedge pressure)
decr wall tension –> decr myocardial O2 demand
2) improve perfusion of ischemic myocardium
when to use nitrates
sublingual –> BYPASS 1ST PASS hepatic meatbolism
prophylaxis for chronic angina
adverse reaction of nitrates
1) orthostatic hypotension
2) reflex tachycardia
3) tachyphylaxis with continuous exposure
nitrates DDI
with sildenafil/vardenafil/tadalafil
–> severe hypotension with vasodilator
where does dihydropyridines act
a
where does verapamil/dilt act
a
a
a
a
a
uses of CCB
1) angina - decr periph vascular resistance
2) arrhythmia (cardiac tissue) = verap/dilt
a
a
a
a
a
a
a
a
a
a
a
a
nonselective b1 and b2 blockers
propranolol
b1 selective (dose dependent)
metoprolol
atenolol
a1, b1, b2 vasodilators
labetalol
carvedilol
