chapter 45: calcium channel blockers Flashcards

1
Q

what are three overall therapeutic uses of calcium channel blockers

A

hypertension, angina pectoris and cardiac dysrhythmias

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2
Q

what do calcium channel blockers have the greatest effect on

A

heart and vascular smooth muscle

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3
Q

what are calcium channels

A

gated pores in cytoplasmic membrane that regulate entry of calcium into cells

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4
Q

what do calcium channels regulate in the VSM

A

contraction

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5
Q

what do calcium channels act on in the VSM

A

peripheral arterioles and arterioles in the heart

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6
Q

action potential causes calcium channels to do what

A

calcium channels open and ions move inward which causes contraction

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7
Q

what do calcium channels do in the heart

A

helps regulate function of the myocardium, SA and AV

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8
Q

what are calcium channels coupled to

A

beta1 adrenergic receptors

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9
Q

what happens if calcium channels are blocked

A

relaxation

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10
Q

what do calcium channel blockers do to inotropic effect, force of contractility, heart rate and dromotopic effect?

A

all are decreased

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11
Q

what type of chronotropic effect does calcium have?

A

positive

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12
Q

what type of inotropic effect does calcium have?

A

positive

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13
Q

what type of dromotropic effect does calcium have?

A

positive

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14
Q

what CCB works on arterioles at therapeutic doses?

A

nefedipine

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15
Q

if nifedipine dose becomes toxic, what effects could it produce?

A

significant cardiac suppression

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16
Q

what could nifedipine help with

A

coronary perfusion

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17
Q

what effect does nifedipine have on heart rate and force of contractility?

A

normally does not effect these two in any way

18
Q

what CCBs work on arterioles and the heart?

A

verapamil and diltiazem

19
Q

what is an indirect effect seen with verapamil and diltiazem

A

reflex tachycardia

20
Q

what are the three net effects seen with verapamil and diltiazem?

A

vasodilation, reduced arterial pressure, increased coronary perfusion

21
Q

where does blockade occur with verapamil and diltiazem?

A

peripheral arterioles that result in dilation, arteries and arterioles in heart, SA node, AV node, myocardium

22
Q

what does blockade on peripheral arterioles lead to?

A

decreased arterial pressure and decreased vascular resistance

23
Q

blockade on arteries and arterioles in heart has what effect?

A

improving coronary perfusion

24
Q

blockade in SA and AV node has what two effects?

A

decreased heart rate and decreased AV impulses

25
the blockade on myocardium of the heart produces what effect?
decreased contractility
26
a patient comes into the clinic complaining of constipation and headache. during your assessment you notice flushing and slight edema in their ankles. what CCB do you suspect they may be taking?
verapamil or diltiazem
27
what are the effects that verapamil/diltiazem can have on the heart
symptomatic bradycardia (SA node blocked), partial or complete AV block or decreased contractility (myocardium blocked)
28
what drug should you not use a BB with?
verapamil/diltiazem
29
what are 3 drug-drug interactions with verapamil/diltiazem?
digoxin, beta-adrenergic blockers, grapefruit juice
30
what can concurrent use of verapamil and metaprolol cause?
massive cardiac suppressions
31
what are the therapeutic uses for nifedipine
hypertension and angina pectoris
32
what can nifedipine NOT be used for?
cardiac dysrhythmias
33
where are nifedipine direct effects located?
VSM
34
what does nifedipine help increase?
force of contractility
35
what drug can nifedipine be given concurrently with?
beta-adrenergic blocker
36
nifedipine has no opposition for what?
reflex tachycardia
37
what formulation of nifedipine safer to use?
sustained release rather than immediate release
38
a rapid decrease in BP with nifedipine can cause what?
will stimulate the baroreceptor reflex which can cause reflex tachycardia
39
what are the direct effects experienced with nifedipine
peripheral vasodilation and increased coronary perfusion
40
what is the one ADR seen with verapamil that is NOT seen with nifedipine?
constipation
41
what is a positive drug interaction with nifedipine
beta-adrenergic blockers
42
what is nifedipine the preferred drug for?
AV heart block, heart failure, or bradycardia