Angina - Chap 12

Question 1

the most important of therapeutic nitrates

Answer 1

nitroglycerin (NG) aka glyceryl trinitrate

Question 2

in what situation would you want to take a transdermal NG?

Answer 2

for prophylaxis (8 to 10 hours duration of action)

Question 3

where is NG denitrated?

Answer 3

in the liver - first to dinatrate (very active v/d) then to mononitrate (less active)

Question 4

true or false: the first pass effect of ng is very high

Answer 4

true - about 90%

Question 5

nitrates release _____ within smooth muscle cells probably through the action of mitochondrial enzyme ALD2

Answer 5

nitric oxide

Question 6

NO released from nitrates stimulate _____ and causes an increase of the second messenger _____.

Answer 6

guanylyl cyclase; cGMP (this then results in relaxation of the smooth muscle)

Question 7

smooth muscle relaxation by nitrates leads to venodilation which then does what to cardiac size and output? (and more importantly, HOW does it do this?)

Answer 7

reduces cardiac size and c/o through reduced preload

Question 8

nitrates may also cause arterial relaxation which will do what to help reduce afterload? what then happens to ejection fraction?

Answer 8

increase flow through partially occluded coronary arteries which may contribute to an increase in ejection fraction and a further decrease in cardiac size

Question 9

what does venodilation do to the size of the diastolic heart?

Answer 9

decreases it

Question 10

what is the effect of nitrates on cardiac muscle?

Answer 10

no direct effect

Question 11

what happens when nitrates reduce BP? (remember that the nitrates will cause arterial dilation which reduces tpr and decreases bp) THINK in terms of compensation …

Answer 11

rebound tachycardia and increased force of contraction - again this is a compensatory effect of the baroreceptor mechanism

Question 12

what do nitrates do to other smooth muscles?

Answer 12

they will relax these muscles (GI, bronchi, UG) BUT the effects here are too small to really be felt.

Question 13

what does IV NG do to platelet aggregation?

Answer 13

reduces it; which is why this is often given to treat unstable angina

Question 14

what is the standard form of NG for treatment of acute anginal pain?

Answer 14

sublingual tablet or spray

Question 15

if you do not have sublingual nitrate or the spray version of NG what is the next best option?

Answer 15

isosorbide dinitrate which has duration of 30 minutes

Question 16

after what period of time does one begin to develop nitrate tolerance?

Answer 16

8 to 10 hours, which is why those wearing a patch are told to remove them after 10 - 12 to allow recovery of sensitivity to the drug

Question 17

the most common toxic effect of nitrates are mainly due to what?

Answer 17

the responses evoked by the v/d.

Question 18

what are the three most common toxic effects of nitrates?

Answer 18

tachycardia, HA, and orthostatic hypotension (and sometimes dizziness due to the latter)

Question 19

nitrates interact with drugs such as sildenafil - what is the MOA for these drugs?

Answer 19

inhibit phosphodiesterase isoform (PDE5) that metabolizes cGMP in smooth muscle. (thus causing further v/d)

Question 20

what are the two main problems of the synergistic effects of both nitrates and PDE5 inhibitors?

Answer 20

orthostatic hypotension and inadequate perfusion to critical organs

Question 21

nitrites at high levels cause what toxic effect in the blood?

Answer 21

methemoglobinemia

Question 22

nitrates or nitrites - which is used in the treatment of cyanide poisoning?

Answer 22

nitrites

Question 23

to what class does the drug nifedipine belong to?

Answer 23

CCB; specifically a dihydropyridine

Question 24

to what class does the drug diltiazem belong to?

Answer 24

CCB

Question 25

true or false: all ccbs are orally active

Answer 25

true

Question 26

by reducing the itc concentration of calcium, ccbs do what do contractility?

Answer 26

reduce muscle contractility (they will actually reduce the rate and contractility)

Question 27

which channels do the drugs verapamil, and diltiazem specifically block - and how does this work?

Answer 27

blocks calcium dependent conduction of the AV node

Question 28

which drugs should be used to treat AV nodal arrhythmias?

Answer 28

CCBs: verapamil and diltiazem

Question 29

true or false nifedipine (and other dihydropyridines) are better v/d than verapamil.

Answer 29

true

Question 30

CCB toxic effects range from mild to severe. what is the most common mild effect? and name 2 of the more severe

Answer 30

constipation; av blockade and heart failure. (note: most common with verapamil and less common with dihydropyridines)

Question 31

this is the class of drugs that are known to reduce the cardiac work of the heart and the oxygen demand.

Answer 31

beta blockers

Question 32

true or false: beta blockers are of no help in an acute anginal episode

Answer 32

true - beta blockers should really only be used in a prophylaxis situation

Question 33

why is it that the combination of beta blockers and nitrates is preferred?

Answer 33

b/c the adverse effects of the nitrates (the compensatory effects that is) are blocked by the beta blockers - b/c remember, nitrates will causes tachycardia and increased cardiac force!

Question 34

new drug that works by reducing late, prolonged sodium content in myocardial cells. (the reduced sodium leads to an expulsion of the calcium and thus leads to reduction in cardiac force)

Answer 34

ranolazine

Question 35

drug that inhibits i2 sodium current of the SA node. the reduction in this hyper-polarization induced inward pacemaker current leads to what?

Answer 35

ivabradine; decreased HR and decrease c/o

Question 36

what are the three classes of drugs used to treat angina?

Answer 36

v/d, cardiac depressants, and “other”

Question 37

what type of meds should be first line treatment for pts suffering from an attack of unstable angina?

Answer 37

platelet inhibitors and of course iv nitro

Question 38

which one of these three drugs will reduce oxygen requirement, but will NOT increase o2 delivery by reducing spasms? ccb, nitrates or beta blockers?

Answer 38

beta blockers - remember that these are contraindicated in patients suffering from variant angina.

Question 39

which new class of anti-anginal drugs will increase efficiency of oxygen utilization by shifting energy substrate preference of the heart from fatty acids to glucose?

Answer 39

pFox inhibitors (partial fatty acid oxidation inhibitors)

Question 40

what class of drugs do these belong to? ranolzine, trimetazidine

Answer 40

pFox

Question 41

what is this drug? its MOA is to act by inhibiting the SA pacemakers current, “If”

Answer 41

ivabradine