Term
What are calcium channels?
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Definition
Gated pores in the cytoplasmic membrane that regulate calcium entry into cells. |
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Term
In blood vessels, what does calcium entry into the cell cause?
What do calcium channel blockers cause? |
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Definition
Vasoconstriction
Vasodilation |
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Term
What does calcium entry into the heart cause?
What effect does calcium channel blockers have on the heart? |
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Definition
1. Increased HR
2. Increased contractility
3. Increased AV Conduction
The opposite effect. |
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Term
In the heart, calcium channels are coupled with beta1 receptors, activation of which enhances calcium entry.
Consequently, calcium channel blockers and beta blockers have identical effects on cardiac function.
True or False
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Definition
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Term
What is the prototype for the Dihydropyridines and where do they act primarily?
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Definition
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Term
What are the 3 main groups of Calcium Channel Blockers? |
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Definition
1. Dihydropyridiens (nifedipine)
2. Diphenylalkylamines (Verapamil)
3. Benzothiazepines (Diltizem) |
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Term
Where does and Diltizaen act? |
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Definition
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Term
All CCB's promote vasodiltation, and are useful in HTN and angina pectoris.
True or False |
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Definition
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Term
Because Verapamil suppresses AV conduction, what else is Verapamil and Diltilazem useful in treating? |
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Definition
Cardiac Dysrythmias
(in addition to HTN and angina pectoris) |
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Term
Because of their cardiosuppressant effects, Verapamil and Diltiazem can cause what 3 cardiac problems? |
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Definition
1. Bradycardia
2. AV Block
3. Exacerbation of heart failure |
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Term
B0eta Blockers do not intensify cardiosuppression caused by Verapamil and Diltiazem.
True or False |
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Definition
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Term
What problem can nipedipine and other dihydropyridines cause? |
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Definition
Reflex Tachycardia
Most intense with rapid acting formulations and much less intense with SR formulations. |
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Term
What can you use to suppress reflex tachycardia when using calcium channel blockers?
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Definition
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Term
Because they cause vasodilation, what are 3 common SE's of CCB's?
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Definition
1. dizziness
2. headache
3. peripheral edema |
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Term
In toxic doses, what can nifedipine cause that is like verapamil and diltiazem? |
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Definition
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Term
What has fast acting nifedipine been associated with? |
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Definition
increased mortality in patients with
1. MI
2. unstable angina
Should be used with extreme caution, if at all. |
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Term
WHat are the actions of CCB's? |
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Definition
dec myocardial contractility
dec HR
dec AV Node conduction |
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Term
What are the direct effects of Verapamil?
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Definition
1. Dilation of arterioles - dec BP
2. Blockage at arteries / arterioles of heart - inc coronary perfusion
Some
3. Blocks SA Node -
4. Block AV Node
5. Block myocardial contractility |
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Term
What are the therapeutic uses of Verapamil? |
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Definition
1. Angina
2. HTN
3. Dysrythmias |
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