sympathomimetic

Question 1

What are the 3 natural human direct acting sympathomimetic neurotransmitters and hormones?

Answer 1

Epinephrine, norepinephrine, and dopamine

Question 2

Name five synthetic direct receptor sympathomimetic agonists

Answer 2

phenylephrine
clonidine
isoproterenol
dobutamine
albuterol

Question 3

Name four indirect acting sympathomimetic drugs

Answer 3

ephedrine
amphetamine
tyramine
cocaine

Question 4

Name the four steps from tyrosine to epinephrine and what happens in each step

Answer 4

tyrosine —> dopa (tyrosine hydroxylase adds OH)
dopa —> dopamine (L-dopa decarboxylation)
dopamine —> norepinephrine (OH on the beta carbon)
norepinephrine —> epinephrine (methylation of the N)

Question 5

What two enzymes break down NE?

Answer 5

COMT and MAO (both but in either order)

Question 6

What are the two direct alpha agonists?

Answer 6

phenylephrine

clonidine

Question 7

What are the three mixed alpha/beta agonists?

Answer 7

epinephrine
norepinephrine
dopamine

Question 8

What are the four beta agonists?

Answer 8

isoproterenol
dobutamine
albuterol
mirabegron

Question 9

phenylephrine pharmacodynamics?

Answer 9

synthetic alpha receptor agonist, much greater effect on a1 than a2 receptors

Question 10

What are the actions of phenylephrine?

Answer 10

vasoconstriction

venoconstriction

Question 11

Why might we prescribe phenylephrine?

Answer 11

nasal congestion
pupil dilation
to increase BP in vasodilator state during anesthesia

Question 12

How can phenylephrine be given?

Answer 12

topical (nasal spray) or intravenous

Question 13

is phenylephrine more or less potent than NE?

Answer 13

less

Question 14

clonidine pharmacodynamics?

Answer 14

synthetic alpha receptor agonist selective for a2

Question 15

what are the actions of clonidine

Answer 15

down regulation of SANS via a2 receptors in brainstem

Question 16

Why would we prescribe clonidine?

Answer 16

treatment of hypertension and or prevent migraines

Question 17

How is clonidine given?

Answer 17

oral or patch

Question 18

Are there any dangers to clonidine?

Answer 18

intravenous or OD can cause low blood pressure

Question 19

How does dobutamine work?

Answer 19

synthetic b1 receptor agonist, very little alpha stimulation at high doses

Question 20

What are the actions of dobutamine?

Answer 20

increase heart contractility via b1 receptors (more than it increases HR)
dilation of renal and mesenteric vessels

Question 21

Why would we prescribe dobutamine?

Answer 21

• increase contractility more than heart rate (those in cardiogenic shock where you don’t want to produce tachycardia)

Question 22

How is dobutamine given?

Answer 22

intravenously

Question 23

Side effects of dobutamine?

Answer 23

unwanted tachycardia
hypertension
ectopy

Question 24

How does albuterol work?

Answer 24

synthetic b2 receptor agonist, with a little bit of b1

Question 25

What are the actions of albuterol?

Answer 25

acts to relax smooth muscle to dilate bronchioles or prevent uterine contractions via b2 receptors

Question 26

Why would we prescribe albuterol?

Answer 26

- rescue inhaler for asthma, dilator for COPD | - inhibit premature labor

Question 27

How is albuterol given?

Answer 27

- MDI | - nebulizer

Question 28

side effects of albuterol

Answer 28

anxiety tachycardia tremor

Question 29

How does isoproterenol work?

Answer 29

b1 and b2 agonist

Question 30

isoproterenol actions

Answer 30

- increase contractility - increase HR - increase cardiac conduction

Question 31

how is isoproterenol given?

Answer 31

intravenous

Question 32

other effects to remember with isoproterenol

Answer 32

will also cause vasodilation and tachyarrhythmias

Question 33

How does mirabegron work?

Answer 33

synthetic b3 agonist, small effect on b1 and b2

Question 34

mirabegron actions

Answer 34

b3 receptors on smooth muscle of bladder, reduces detrusor muscle tone

Question 35

Why would we prescribe mirabegron?

Answer 35

- overactive bladder with urgency - to increase bladder capacity - does not produce bothersome anticholinergic symptoms like tolteridine

Question 36

how is mirabegron given?

Answer 36

orally extended release tablets

Question 37

How does epinephrine work?

Answer 37

a1 - peripheral vasoconstriction and venoconstriction (increase preload and SVR) b1 - tachycardia and increased contractility b2 - bronchodilation

Question 38

how can epinephrine be given?

Answer 38

IV, IM, inhalation

Question 39

why would we give epinephrine?

Answer 39

anaphylaxis or cardiac arrest

Question 40

what is the important negative drug interaction with epinephrine?

Answer 40

hypertension when combined with propranolol

Question 41

what are the possible consequences of toxicity with epinephrine?

Answer 41

- vasoconstriction - HTN - hemorrhagic stroke - angina - arrhythmias

Question 42

how does norepinephrine work?

Answer 42

a1 - vaso and venoconstriction | b1 - HR and contractility increase

Question 43

how is norepinephrine given?

Answer 43

IV only

Question 44

what are consequences of norepinephrine toxicity?

Answer 44

- constriction of mesenteric vessels and peripheral arterioles causing ischemia, infarction, gangrene, reflex bradycardia

Question 45

when should we be cautious about prescribing NE?

Answer 45

- someone taking a MAO inhibitor such as phenelzine | - risk of hypertension when combined with propranolol

Question 46

why would we prescribe NE?

Answer 46

acute hypotension and shock

Question 47

how does ephedrine work?

Answer 47

indirect - releases NE from adrenergic nerve endings | some direct agonism at receptors

Question 48

why would we prescribe ephedrine?

Answer 48

- mild to moderate hypotension during surgery - nasal congestion - bronchodilation?

Question 49

side effects of ephedrine?

Answer 49

- hypertension - insomnia - CNS stimulation.....

Question 50

how does pseudo ephedrine work?

Answer 50

indirect - releases NE from adrenergic nerve endings | some direct a and b agonism

Question 51

why would we prescribe pseudoephedrine?

Answer 51

- nasal and sinus decongestant | - bronchodilation but less than ephedrine

Question 52

how does tyramine work?

Answer 52

- acts indirectly to release NE from adrenergic nerve endings

Question 53

What are indications for tyramine? (not FDA approved)

Answer 53

- obesity - narcolepsy - ADHD

Question 54

Risks with tyramine?

Answer 54

- should not be combined with phenelzine (MAO inhibitor)

Question 55

how does cocaine work?

Answer 55

indirect - blocks reuptake of NE, epinephrine, and DA at the synapse and can also stimulate NE release

Question 56

why would we prescribe cocaine?

Answer 56

nose bleeds | anesthesia for corneal surgery

Question 57

how do amphetamines work?

Answer 57

indirect - release NE from adrenergic nerve endings

Question 58

indications for amphetamine

Answer 58

obesity, narcolepsy, ADHD

Question 59

phenylephrine F

Answer 59

38%

Question 60

how is phenylephrine metabolized?

Answer 60

liver

Question 61

phenylephrine half life

Answer 61

2-3 hours, short

Question 62

isoproterenol half life

Answer 62

2 minutes, extremely short

Question 63

clonidine F

Answer 63

60-95%, high

Question 64

clonidine metabolism

Answer 64

liver to inactive metabolites

Question 65

clonidine half life

Answer 65

8 hours

Question 66

dobutamine half life

Answer 66

2 minutes, extremely short

Question 67

albuterol metabolism and excretion

Answer 67

- metab - hepatic | - excretion - renal

Question 68

albuterol half life

Answer 68

1.6 hours, short

Question 69

ephedrine F

Answer 69

85%

Question 70

ephedrine half life

Answer 70

3-6 hours

Question 71

ephedrine metabolism and excretion

Answer 71

- minimal hepatic metabolism | - 22-99% renal excretion

Question 72

cocaine half life

Answer 72

1 hour

Question 73

amphetamine half life

Answer 73

9-14 hours

Question 74

amphetamine F

Answer 74

75-100%