Calcium Channel Blockers-MJ Flashcards
What happens in the blood vessels when calcium channels are blocked?
Contraction will be prevented and vasodilation will result
What are the three areas in the heart that have calcium channels?
Myocardium, SA node, AV node
Calcium channels at all three sites in the heart are coupled to _____ receptors
Beta1 adrenergic receptors
Calcium flow in the myocardium increases force of contraction. If the calcium channels in the atrial and ventricular muscle are blocked, ______ will diminish.
Contractile force
What is the pacemaker (SA node) activity of the heart regulated by?
Calcium
When calcium channels are open in the SA node, spontaneous discharge of the SA node increases. What happens when we block the calcium channels?
Pacemaker activity declines resulting in reduced HR
Since impulses from the SA node must pass through the AV node on the way to the ventricles, regulation of AV conduction plays a critical role in ________.
Coordinating contraction of the ventricles with contraction of the atria
What is the excitability of AV nodal cells regulated by?
Calcium entry
In the AV node, when calcium channels are open, calcium entry increases and the cells of the AV node discharge more readily. What happens when we block those calcium channels?
Discharge of AV nodal cells is depressed so there is a decrease velocity of conduction through the AV node
What are the two areas where calcium channels are found?
Blood vessels and heart (myocardium, SA node, AV node)
What are the two types of calcium channel blockers?
Dihydropyridines and non-dihydropyridines
What calcium channels receptors do the dihydropyridines block?
Blood vessel ones ONLY
What calcium channel receptors do the non-dihydropyridines block?
BOTH the blood vessel and heart receptors!
What are the 3 drugs of the dihydropyridines?
- Nifedipine XL
- Amlodipine
- Amlodipine/ Benazepril
What are the indications for giving a dihydropyridine medication?
Hypertension
Angina pectoris