Calcium Channel Blockers Flashcards
Location/function of Ca(v)1.2
location: cardiac and smooth muscle
function: Ca2+ entry triggers contraction
block of calcium channels in vascular smooth muscle =
vasodilation (decrease in blood pressure)
block of calcium channels in cardiac muscle and SA/AV node =
anti-arrhythmic
extracellular Ca2+ is required for contraction of _______ and __________ _________ muscle
cardiac
vascular smooth
(NOT skeletal)
three distinct classes of calcium channel blockers
- dihydropyridines
- phenylalkylamines
- benzothiazepines
dihydropyridines are more selective for which tissues?
vascular smooth muscle (especially the coronary artery)
they do not compromise cardiac function
DHP drugs bind to ______ channels and prevent _________. This is known as a ______ block.
closed, opening, tonic
*since the channel is closed, DHP drugs bind to an allosteric site that is not in the pore
amlodipine has ______ onset and ______ duration of action
slow
long
phenylalkylamines (verapamil) are ______ potent than DHPs
less
does verapamil bind to an open or closed calcium channel? what is this known as?
open in order for the drug to enter the pore
this is known as a frequency-dependent block
rank the inhibitory effects of the three classes of calcium channel blockers from greatest to least
verapamil»_space; diltiazem > DHPs
what kind of block do benzothiazepines exhibit?
some tonic, some frequency dependence *diltiazem exhibits frequency dependence block
which calcium channel blockers have the highest arteriole vasodilation?
DHPs
how does each CCB affect heart rate?
verapamil - large decrease
DHPs - increase
diltiazem - decrease
what side effect do all CCBs have in common?
ankle edema
