Test 3: 33 cardio drugs

Question 1

how do vasodilators effect arterial blood pressure

Answer 1

decreases total peripheral resistance (arterial vascular smooth muscle tone →vasodilation = ↓afterload)

↓ venous return to the heart = ↓preload

Question 2

how do positive inotropic drugs effect arterial blood pressure

Answer 2

change myocardial contraction which changes stroke volume → changes cardiac output

Question 3

— are some common ace inhibitors

Answer 3

benazepril
enalapril

type of vasodilator

Question 4

— is a type of ARB

Answer 4

telmisartan

Question 5

— are two inotropes used in vet med

Answer 5

digoxin and pimobendan

Question 6

arteriodilators can decrease mitral regurgitation in dogs with DCM by

Answer 6

increasing the size of the aorta= decrease afterload

will cause more blood out through the aorta and less going backwards into the atrium

Question 7

— is a venous dilator medication

Answer 7

nitroglycerin

Question 8

— are balanaced vasodilators

Answer 8

ACE inhibitors (enalapril)
Nitrates (nitroprusside)

Question 9

— are arteriodilators

Answer 9

hydralazine
amlodipine

Question 10

goal of ACE inhibition

Answer 10

stop angiotensin II which causes

fluid and Na retention
vasoconstriction
increased thirst
vascular and myocardial fibrosis and pathologic tissue remodeling
increases aldosterone

Question 11

which ACE inhibitor is less toxic in patients with exisiting renal disease

Answer 11

Benazepril

Question 12

what is an ARB

Answer 12

angiotensin II receptor blocker
telmisartan

bind to AT1 receptors which cause hypertension and vasocontriction

does not bind to AT2 receptors which cause good things: vasodilation and Natriuretic

Question 13

side effects of ACE inhibitors

Answer 13

hypotension
renal impairment (need to check renal function after starting meds)
↑ potassium
anorexia, diarrhea, vomiting
cough?

enalapril

Question 14

if patient gets cough on ACE inhibitor then can start —

Answer 14

ARB (telmisartan)

Question 15

what are the three main nitrates used

Answer 15

nitroglycerin
isosorbide (mono-, di-) nitrate
nitroprusside

Question 16

how do nitrates work

Answer 16

exact mechanism not known but nitrates cause the release of NO which will cause vasodilation by the formation of cGMP

Question 17

why do paitents become tolerant to nitrates

Answer 17

↓ sulfhydryl(SH) groups

can prevent tolerance by staggered therapy- give for 5 days, give weekend off

Question 18

Isosorbide mononitrate is metabolized where

Answer 18

not the liver

Question 19

how do arteriodilators reduce myocardial workload

Answer 19

• reduce systemic BP
• reduce afterload and myocardial wall stress
• unloads the failing heart

Question 20

what happens with high dose IV nitroprusside

Answer 20

toxic

coverts to methemoglobin which pushed curve to the left: RBC won’t let go of O2

nitroprusside: balanced vasodilator: both arteriodilator and venodilator

Question 21

when to use nitroprusside

Answer 21

bad cases of CHF that are not responding to normal therapy

HTN crisis

does not need SH to release NO → vasodilation
balanced vasodilation: both arterio and venodilator

Question 22

adverse effects of nitroprusside

Answer 22

hypotension
reflex tachycardia

does not need SH to release NO → vasodilation
balanced vasodilation: both arterio and venodilator

Question 23

how does hydralazine work?

Answer 23

unknown

increases cGMP → vasodilation= ↓afterload

Question 24

adverse effects of hydralazine

Answer 24

hypotension
reflex tachycardia
GI: vomiting and anorexia

Question 25

--- is a dihdropyridine calcium channel blockers

Answer 25

amlodipine ## Footnote treat ↑BP with no effect on heart rate or inotropic state

Question 26

--- are non-dihydropyridine calcium channel blockers

Answer 26

verapamil diltiazem ## Footnote will ↓BP and control HR (antiarrhthymic)

Question 27

side effect of amlodipine in dogs

Answer 27

gingival hyperplasia ## Footnote amlodipine: dihdropyridine calcium channel blocker that ↓ BP without effecting HR

Question 28

--- are naturally occurring catecholamines

Answer 28

sympathomimetics epinephrine norepinephrine dopamine

Question 29

what 4 receptors are effected by beta agonist in the heart

Answer 29

L type Ca channel phospholamban Troponin I RYR2

Question 30

--- drugs work on the beta adrenergic receptor in the heart

Answer 30

dopamine dobutamine

Question 31

--- is a phosphodiesterase inhibitor

Answer 31

pimobendan (balanced vasodilator)

Question 32

--- drugs works on the Na/K ATP pump in the heart

Answer 32

digoxin

Question 33

compare effect of dopamine nad dobutamine on systemic vascular resistance and cardiac output

Answer 33

Question 34

how does pimobendan work

Answer 34

increases binding of Ca to troponin in the cardiac cell = ↑ myocardial contractility does not increase the amount of Ca in a cell and does not increase energy demand of the cell inhibits phosphodiesterase will also cause arterio and venodilation

Question 35

compare pimobendan and digoxin

Answer 35

**primobendan** increases contractility of heart by increasing troponins sensitivity to Ca that is already there= no increase in Ca into the cell and no increase in energy demand of the cell **digoxin** will inrease the amount of Ca into a cell to cause increased contraction

Question 36

if you give pimodendan to dog with asymptomatic heart disease what will happen

Answer 36

reduces onset of CHF for average of 15 months

Question 37

how does digoxin effect HR

Answer 37

slows conduction by SA node slows conduction through AV node increases refractory period in the AV node used to **treat Afib**

Question 38

what happens with digoxin toxicity

Answer 38

narrow therapeutic window cause cardiac arrhythmias (AV block, ventricular bigeminy) Vomiting, diarrhea, anorexia and weight loss depression

Question 39

how to prevent digoxin toxicity

Answer 39

start at low dose dose on body surface area check a serum level after 5-7 days

Question 40

how to treat digoxin toxicity

Answer 40

stop drug treat symptoms can give antibody Digibind if symptoms resolve can restart at lower dose

Question 41

dopamine at low dose

Answer 41

B receptor: increases HR and contactility, cause **vasodilation** ## Footnote at high dose: binds to alpha adrenergic receptors and causes vasoconstrictiona and ↑HR

Question 42

dopamine at high dose

Answer 42

act on **Alpha 1 receptors** cause **vasoconstriction** and ↑HR ## Footnote **at low dose**: B receptors: ↑HR and contractility sopaminergic receptors cause **vasodilation**

Question 43

--- is primary ⍺1 agonist vs --- is primary β1 agonist

Answer 43

dopamine (cause vasoconstriction and ↑HR) dobutamine ( inotropic agent= increases intracellular Ca= increase contraction with minimal effect on heart rate)

Question 44

what does a B1 adrenergic agonist do

Answer 44

dobutamine increases contraction of the heart without effecting HR does not increase O2 demand of the heart

Question 45

dopamine or dobutamine should be given to treat CHF

Answer 45

**dobutamine**: B1 receptor= + inotropic drug= increases contraction of the heart dopamine is a vasopressor= alpha 1 receptor= cause vasocontraction and increases systemic vascular resistance = used to treat sepsis

Question 46

--- increase myocardial contractility and are used in the setting of heart failure.

Answer 46

Positive inotropic agents (catecholamines/dobutamine, digoxin→increase Ca into a cell) (pimobendan →increase binding of Ca to myosin)