Flashcards in ischemia3 Deck (37)
what is the half life of nitroglycerin
what are the two active metabolites of nitroglycerin
glyceryl 1, 2-dinitrate
glyceryl 1, 3-dinitrate
what is the active metabolite of isosorbide dinitrate (ISDN)?
why is isosorbide 5-mononitrate preferred
4 hour half life
what nitrates are used for angina prevention
ISDN and ISMN
how would you counsel a patient taking both NTG and sildinafil
48 hours before taking nitrates with Cialis
others 24 hours before taking nitrate
what dosing form is best for a patient with chest pain at night
(drug free in afternoon)
what is preferred ISMN or ISDN?
why (4 reasons)?
longer half life
almost completely absorbed
less rebound angina
what type of Ca channel is in vascular smooth muscle?
what is it's rate like?
voltage gated L-type Ca channels
what is calcium entering a vascular smooth muscle's effect on MLCK
what are the 3 main mechanisms of contraction of vascular tissue?
which is the main one CCB's inhibit?
1. voltage sensitive Ca channels open in response to depolarization
2. agonist induced release of calcium from SR
3. receptor mediated entry of calcium
what has an inhibitory effect in cardiac cells
what stops troponin's effect in cardiac cells
calcium binding (stops inhibition)
what effect do CCBs have on cardiac cells
negative inotropic effect
the negative ionotropic effect of dihydropyridines is caused by what?
peripheral dilation leading to baroreceptor reflex
what is CCB's effect on force of contration
what is another term for inotropic effect on the heart
force of contraction
dihyropyridines peripheral dilation causes an increase in what?
what can this effect overcome?
increase SNS tone
can overcome negative inotropic effects on heart (why non-dihydro are better for myocardial ischemia)
what is significantly effected by nondihydropyridines
SA and AV nodes
what rate is not changed from dihydropyridines
does not change rate of recovery from Ca inhibition
what decreases rate of recovery from inhibition in cardiac cells
what CCBs show use/ frequency dependance
list the two nondihydropyridines
all CCB's have what effect
arrange these drugs in order of ability to increase blood supply (coronary blood flow):
diltiazem, verapamil, dihydropyridines
dihydropyridines> verapamil > Diltiazem
what CCBs increase coronary blood flow the most
what are dihydropyridines effects on BP? what does this lead to?
decrease BP leading to:sympathetic reflexes
SNS reflexes cause increased HR and FOC
what CCBs have most potent inotropic effects
CCB's have little effect on what related to blood flow
venous tone (so A > V)