Pressors/cardiac

Question 1

What receptor(s) does dopamine act on?

Answer 1

alpha-1, alpha-2, beta-1, dopamine

Question 2

What is the effect of dopamine at low doses?

Answer 2

low dose = 1-5mcg/kg/min
-increases renal blood flow
-little change in cardiac output or total peripheral resistance

Question 3

What is the effect of dopamine at intermediate doses?

Answer 3

intermediate dose = 5-20mcg/kg/min
-increased cardiac output and heart rate
-increased renal perfusion

Question 4

What is the effect of dopamine at high doses?

Answer 4

high dose = >20mcg/kg/min
-renal vasoconstriction
-increased total peripheral resistance
-increased blood pressure

Question 5

What is the dosing for adenosine in a pt w/ narrow complex tachycardia who is HD normal? How many times can you give it?

Answer 5

-first dose = 6mg IVP
-second dose = 12mg IVP
-if 3rd dose of 12mg doesn’t work then sedate and cardiovert

-make sure you have a good IV line because it metabolizes quickly

Question 6

What is the endogenous precursor to norepinephrine? What amino acids are the precursor to this?

Answer 6

-dopamine
-dopamine comes from phenylalanine or tyrosine

Question 7

Which receptors does norepi primarily act on?

Answer 7

alpha-1 receptors in the peripheral vasculature
-also alpha-2 and beta-1

Question 8

What is the vascular effect of norepi?

Answer 8

vasoconstriction

Question 9

What is the process that converts norepi to epi?

Answer 9

methylation

Question 10

What receptors does epinephrine act on?

Answer 10

beta-1, beta-2, alpha-1

Question 11

What are the effects of epi on the heart?

Answer 11

-increased HR (chronotropy)
-increased contractility (inotropy)

Question 12

What is the basic MOA of milrinone?

Answer 12

selective inhibitor of phosphodiesterase-3
-this is an enzyme that degrades cAMP and cGMP
-inhibition of this enzyme leads to reduced rate of cAMP degradation

Question 13

What are the effects (broad terms) of milrinone?

Answer 13

-increase in inotropy
-vasodilation
-mild increase in chronotropy

Question 14

What is the postulated reason that milrinone improves diastolic dysfunction?

Answer 14

it might have a direct effect on the myocardium via enhancement of sacromere uptake of Ca ions

Question 15

What are the broad effects of alpha-1 receptors?

Answer 15

smooth muscle contractions, mydriasis

Question 16

What are the broad effects of alpha-2 receptors?

Answer 16

mixed smooth muscle effects

Question 17

What are the broad effects of beta-1 receptors?

Answer 17

increased cardiac chronotropic and inotropic effects

Question 18

What are the broad effects of beta-2 receptors?

Answer 18

bronchodilation

Question 19

What are the broad effects of beta-3 receptors?

Answer 19

-increased lipolysis
-some smooth muscle action as it it used for overactive bladder

Question 20

What are examples of drugs that are selective alpha-1 binders?

Answer 20

phenylephrine and oxymetazoline

Question 21

What are examples of drugs that are selective alpha-2 binders?

Answer 21

methyldopa and clonidine

Question 22

What are examples of drugs that are selective beta-1 binders?

Answer 22

dobutamine

Question 23

What are examples of drugs that are selective beta-2 binders?

Answer 23

alubterol

Question 24

What is phenylephrine used for? Which receptors does it work on?

Answer 24

Decongestant and vasopressor; good for hypotension d/t shock; priapism; alpha-1

Question 25

What is clonidine used for? Which receptors does it work on?

Answer 25

HTN, ADHD, PTSD, restless leg, hot flashes w/ menopause; alpha-2

Question 26

What is dexmedetomidine used for? Which receptors does it work on?

Answer 26

sedation in ICU that does not cause respiratory depression; alpha-2

Question 27

What is dobutamine used for? Which receptors does it work on?

Answer 27

increases CO in cardiogenic shock and heart failure; acts on beta-1

Question 28

What is mirabegron used for? Which receptors does it work on?

Answer 28

overactive bladder and pediatric neurogenic detrusor overactivity; beta-3

Question 29

What is dopamine used for? Which receptors does it work on?

Answer 29

treatment of bradycardia, hypotension, cardiac arrest; alpha-1, alpha-2, beta-1, dopamine

Question 30

What is isoprenaline used for? Which receptors does it work on?

Answer 30

bradycardia, heartblock; beta-1 and beta-2

Question 31

What are common adverse effects of selective alpha-1 agonists?

Answer 31

-HTN -phenylephrine and others can cause reflexive bradycardia

Question 32

What are common adverse effects of selective alpha-2 agonists?

Answer 32

-hypotension -dry mouth -sedation -high doses = respiratory depression and somnolence

Question 33

What are common adverse effects of selective beta-1 agonists?

Answer 33

-tachycardia -palpitations -HTN -can lead to tachyarrhythmias and anxiety

Question 34

What are common adverse effects of selective beta-2 agonists?

Answer 34

-tremors -tachycardia -palpitations -anxiety

Question 35

Is norephinephrine more or less likely to cause arrhythmias?

Answer 35

less likely, thought to be because more alpha-1 selective

Question 36

What are contraindications to alpha-1 receptor agonists?

Answer 36

-HTN -bradycardia -prostatic hyperplasia

Question 37

What are contraindications to alpha-2 receptor agonists?

Answer 37

-hypotension -careful in geriatric pts as it is sedating and may lead to falls

Question 38

What are contraindications to beta-1 receptor agonists?

Answer 38

arrhythmias

Question 39

What are contraindications to beta-2 receptor agonists?

Answer 39

hypokalemia (relative)

Question 40

What are contraindications to norepinephrine?

Answer 40

some anesthetics -can increase of arrhythmias w/ halothane or cyclopropane

Question 41

What are contraindications to epinephrine?

Answer 41

closed angle glaucoma

Question 42

What receptors does dobutamine act on and what is the effect?

Answer 42

-beta-1 and beta-2 -beta-1 increases inotropy/chronotropy, beta-2 decreases afterload, together these increase cardiac output w/o increasing oxygen demand