ch 39 - second

Question 1

How do Calcium Channel Blockers work

Answer 1

Works on vascular smooth muscle:
Myocardium - decreases force of contractility
SA node - reduces heart rate
AV node - decrease velocity of conduction

Question 2

two types of CCBS

Answer 2

dihydropyridines (-pine)

nondihydropyridines (verapamil and diltiazem)

Question 3

At therapeutic doses of dihydropyridines (-pine) work primarily on the

Answer 3

arterioles (vascular smooth muscle)

Question 4

At therapeutic doses of non-dihydropyridines (verapamil and diltiazem) work primarily on the

Answer 4

arterioles and the heart

Question 5

of the direct effects on the heart by nondihydropyridines, what effect is the most important

Answer 5

reduction of AV conduction

Question 6

Explain Verapamil and first pass effect

Answer 6

If given orally instead of IV, the med will undergo extensive metabolism on its first pass through the liver. Only about 20% of an oral dose reaches the systemic circulation.

Question 7

Elimination of Verapamil

Answer 7

Metabolized and eliminated by liver. Someone with liver impairment must have reduced dosing.

Question 8

Class of CCBS approved for HTN, and angina

Answer 8

dihydropyridines

-pine

Question 9

Class of CCBs approved for HTN, angina and dystrhythmia

Answer 9

Nondihyropyridines
Verapamil (Calan, Verelan)
Diltiazem (Cardizem)

Question 10

GI effects for Verapamil

Answer 10

Constipation occurs frequently and is the most common complaint. Can be esp severe in older adults.. - minimized by increasing fluids and fiber

Question 11

Effects of Verapamil and Diltiazem secondary to vasodilation

Answer 11

dizziness
facial flushing
edema of ankles and feet

Question 12

Cardiac effects of Verapamil and Diltiazem

Answer 12

In the SA node, calcium channel blockade can cause BRADYCARDIA

in the AV node, blockade can cause partial or complete AV BLOCK

in the myocardium, blockade can DECREASE CONTRACTILITY

in a healthy pt - rarely clinically significant
kin pt with certain cardiac diseases - this can seriously exacerbate dysfunction

Question 13

Who can you not use Verapamil in? what pt population

Answer 13

Special caution in heart failure

Do not use in
sick sinus syndrome (dysfunctional SA node)
second-degree or third degree AV block

Question 14

Verapamil and Digoxin

Answer 14

Both suppress impulse conduction through the AV node. when used together, the risk for AV block is increased. Monitor closely when using together

Verapamil increases plasma levels of digoxin by about 60%, thereby increasing the risk for digoxin toxicity. IF signs of tox appear, dose should be reduced

Question 15

B blockers and Verapamil

Answer 15

have same effects on the heart - decrease heart rate, av conduction and contractility.

used together, there is risk for excessive cardiosuppression. Administer B Blockers and IV verapamil several hours apart.

Question 16

what CCB carry the highest risk for toxic drug levels when drinking grapefruit juice

Answer 16

felodipine and nifedipine

All still carry risk

Question 17

what CCB carry a risk for toxic drug levels when drinking grapefruit juice (CYP3A4 inhibitor)

Answer 17

felodipine
nifedipine

verapamil
amlodipine
diltiazem

(all CCB would be at risk because metabolized by liver)

Question 18

what type of cardiac dysrhythmias would you use diltiazem for

Answer 18

A-flutter
A-fib
Paroxysmal SVT

Question 19

Diltiazem (Cardizem) metabolism

Answer 19

oral is well absorbed and then extensively metabolized on its first pass through the liver. Bioavailability is only 50%
effects begin rapidly (within a few min)
peaks in 30 min
nearly complete metabolism before eliminated in urine and feces

Question 20

GI effects of Diltiazem compared to Verapamil

Answer 20

less constipation

Question 21

skin effects of Diltiazem

Answer 21

chronic eczematous rash in older adults

Question 22

What CCB can you use in infants to convert certain heart dysrhythmias

Answer 22

Verapamil

Question 23

Children/adolescents and CCBs

Answer 23

used in children to treat HTN, Hypertensive emergencies and hypertrophic cardiomyopathy

Question 24

Pregnancy and CCBs

Answer 24

risk and benefits must be weighed and discussed

Question 25

What CCB may pose harm to infant with breastfeeding

Answer 25

Verapamil

Question 26

What CCB is noted to have data lacking regarding transmission during breastfeeding

Answer 26

Nifedipine

Question 27

What drug class has been associated with chronic eczematous eruptions in older adults

Answer 27

CCBs

Question 28

How does nifedipine increase hr and contractile force

what formulation usually does this?

Answer 28

indirect effect

by lowering BP, it activates the baroreceptor reflex, thereby causing sympathetic stim of the heart.

immediate release, not with the slow release
this is bc the reflex is activated by the rapid fall in bp. The gradual decline will not activate it

Question 29

Net effect of nifedipine

Answer 29

Vasodilation (XR formulation)
reflex cardiac stimulation (XR and IR formulation)

lowers BP
increases HR
increases Contractile force

Question 30

nifedipine metabolism

Answer 30

oral is well absorbed and then extensively metabolized on its first pass through the liver. Bioavailability is only 50%
IR effects begin rapidly (within a few min)
peaks in 30 min
SR formulation - effects begin in 20 min and peak in 6 hours.

fully metabolized before eliminated in urine

Question 31

indications for nifedipine

Answer 31

angina (vasospastic angina, angina of effort)
HTN
Hypertensive emergencies

Question 32

adverse effects of nefedipine

Answer 32

flushing
dizziness
headache
peripheral edema
gingival hyperplasia
chronic eczematous rash in older adults
very little constipation
reflex tachycardia

Question 33

contraindication for nifedipine

Answer 33

pt with history of MI

unstable angina

Question 34

To prevent reflex tachycardia, nifedipine can be combined with

Answer 34

B Blocker (-lol)

Question 35

hypotension caused by B blockers and Verapamil need to be given what drug to correct

Answer 35

Norepinephrine