chapter 45: calcium channel blockers

Question 1

what are three overall therapeutic uses of calcium channel blockers

Answer 1

hypertension, angina pectoris and cardiac dysrhythmias

Question 2

what do calcium channel blockers have the greatest effect on

Answer 2

heart and vascular smooth muscle

Question 3

what are calcium channels

Answer 3

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

Question 4

what do calcium channels regulate in the VSM

Answer 4

contraction

Question 5

what do calcium channels act on in the VSM

Answer 5

peripheral arterioles and arterioles in the heart

Question 6

action potential causes calcium channels to do what

Answer 6

calcium channels open and ions move inward which causes contraction

Question 7

what do calcium channels do in the heart

Answer 7

helps regulate function of the myocardium, SA and AV

Question 8

what are calcium channels coupled to

Answer 8

beta1 adrenergic receptors

Question 9

what happens if calcium channels are blocked

Answer 9

relaxation

Question 10

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

Answer 10

all are decreased

Question 11

what type of chronotropic effect does calcium have?

Answer 11

positive

Question 12

what type of inotropic effect does calcium have?

Answer 12

positive

Question 13

what type of dromotropic effect does calcium have?

Answer 13

positive

Question 14

what CCB works on arterioles at therapeutic doses?

Answer 14

nefedipine

Question 15

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

Answer 15

significant cardiac suppression

Question 16

what could nifedipine help with

Answer 16

coronary perfusion

Question 17

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

Answer 17

normally does not effect these two in any way

Question 18

what CCBs work on arterioles and the heart?

Answer 18

verapamil and diltiazem

Question 19

what is an indirect effect seen with verapamil and diltiazem

Answer 19

reflex tachycardia

Question 20

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

Answer 20

vasodilation, reduced arterial pressure, increased coronary perfusion

Question 21

where does blockade occur with verapamil and diltiazem?

Answer 21

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

Question 22

what does blockade on peripheral arterioles lead to?

Answer 22

decreased arterial pressure and decreased vascular resistance

Question 23

blockade on arteries and arterioles in heart has what effect?

Answer 23

improving coronary perfusion

Question 24

blockade in SA and AV node has what two effects?

Answer 24

decreased heart rate and decreased AV impulses

Question 25

the blockade on myocardium of the heart produces what effect?

Answer 25

decreased contractility

Question 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?

Answer 26

verapamil or diltiazem

Question 27

what are the effects that verapamil/diltiazem can have on the heart

Answer 27

symptomatic bradycardia (SA node blocked), partial or complete AV block or decreased contractility (myocardium blocked)

Question 28

what drug should you not use a BB with?

Answer 28

verapamil/diltiazem

Question 29

what are 3 drug-drug interactions with verapamil/diltiazem?

Answer 29

digoxin, beta-adrenergic blockers, grapefruit juice

Question 30

what can concurrent use of verapamil and metaprolol cause?

Answer 30

massive cardiac suppressions

Question 31

what are the therapeutic uses for nifedipine

Answer 31

hypertension and angina pectoris

Question 32

what can nifedipine NOT be used for?

Answer 32

cardiac dysrhythmias

Question 33

where are nifedipine direct effects located?

Answer 33

VSM

Question 34

what does nifedipine help increase?

Answer 34

force of contractility

Question 35

what drug can nifedipine be given concurrently with?

Answer 35

beta-adrenergic blocker

Question 36

nifedipine has no opposition for what?

Answer 36

reflex tachycardia

Question 37

what formulation of nifedipine safer to use?

Answer 37

sustained release rather than immediate release

Question 38

a rapid decrease in BP with nifedipine can cause what?

Answer 38

will stimulate the baroreceptor reflex which can cause reflex tachycardia

Question 39

what are the direct effects experienced with nifedipine

Answer 39

peripheral vasodilation and increased coronary perfusion

Question 40

what is the one ADR seen with verapamil that is NOT seen with nifedipine?

Answer 40

constipation

Question 41

what is a positive drug interaction with nifedipine

Answer 41

beta-adrenergic blockers

Question 42

what is nifedipine the preferred drug for?

Answer 42

AV heart block, heart failure, or bradycardia