ANS: Pharmacology & Pathophysiology

Question 1

Which agent is NOT removed from the synaptic cleft by reuptake?
a. phenylephrine
b. dopamine
c. norepinephrine
d. epinephrine

Answer 1

a. phenylephrine

Question 2

The ANS contrlols our

Answer 2

involuntary regulatory functions, “fight or flight responses”

Question 3

_______ is a commonly used sympathomimetic in routine anesthetic care.

Answer 3

Phenylephrine

Question 4

Phenylephrine has _____________________ activity

Answer 4

selective and direct alpha 1 agonist

Question 5

What is the MOA of clonidine and dexmedetomidine?

Answer 5

centrally acting alpha 2 receptor agonists

Question 6

Clonidine and dexmedetomidine produce

Answer 6

sedation
anxiolysis
decreased BP & HR
cause analgesia

Question 7

What are examples of categories of ANS modifiers?

Answer 7

adrenergic agonists
synthetic catecholamines
ARBs,
direct vasodilators/nitrodilators
antimuscarinics

Question 8

Examples of adrenergic agonists include

Answer 8

epinephrine, norepinephrine, dopamine

Question 9

Examples of synthetic catecholamines include

Answer 9

isoproterenol, dobutamine

Question 10

Examples of synthetic noncatecholamines include

Answer 10

ephedrine
phenylephrine

Question 11

Examples of selective beta-adrenergic agonists

Answer 11

albuterol, salmeterol

Question 12

Examples of anesthetic agents include

Answer 12

volatile agent, propofol, local anesthetics

Question 13

The ANS relies on two neurotransmitters:

Answer 13

ACh and norepinephrine

Question 14

All ganglionic neurotransmission is

Answer 14

cholinergic (ACh)

Question 15

Postganglionic parasympathetic neurotransmission is

Answer 15

cholinergic (ACh)

Question 16

Postganglionic sympathetic neurotransmission is

Answer 16

adrenergic (NE)

Question 17

How is phenylephrine metabolized?

Answer 17

MAO

Question 18

How is the effect of phenylephrine on renal blood flow?

Answer 18

decreased

Question 19

Does phenylephrine affect the venous AND arterial vasoconstriction?

Answer 19

yes, pure agonist at alpha 1 adrenoreceptors in venous and arterial

Question 20

Significant reflex bradycardia may occur with the administration of phenylephrine because of

Answer 20

baroreceptor activity

Question 21

Just as with norepinephrine, with phenylephrine there is a risk of

Answer 21

end-organ damage especially with high dose and/or prolonged duration of infusion

Question 22

_______________ increases with phenylephrine due to direct vasoconstrictive action of the drug in the lung vasculature.

Answer 22

pulmonary artery pressure

Question 23

If there is a phenylephrine overdose, what is the best course of action?

Answer 23

an alpha 2 adrenergic receptor antagonist such as phentolamine
depending on degree of hypertension and patient’s baseline condition time may be all that is needed
DO not treat with a beta receptor antagonist

Question 24

Beta receptor antagonists are contraindicated in a phenylephrine overdose because

Answer 24

they may induce pulmonary edema and catastrophic, irreversible cardiovascular collapse

Question 25

What are the three ways in which the location of alpha 2 receptors are classified?

Answer 25

1. presynaptic: NE-releasing neurons in the CNS and PNS (negative feedback mechanism reduces NE release)
2. postsynaptic: smooth muscle and several organs
3. Nonsynaptic: platelets

Question 26

Alpha 2 receptors in the GI tract have the physiologic effect of

Answer 26

decreased gut motility

Question 27

Alpha 2 receptors in the salivary glands have the physiologic effect of

Answer 27

dry mouth (thick, viscous saliva)

Question 28

Alpha 2 receptors in the platelets have the physiologic effect of

Answer 28

increased platelet aggregation

Question 29

Alpha 2 receptors in the pancreas have the physiologic effect of

Answer 29

decreased insulin release

Question 30

Alpha 2 receptors in the renal tubules have the physiologic effect of

Answer 30

inhibiting ADH (diuresis)

Question 31

Alpha 2 receptors in the vasculature have the physiologic effect of

Answer 31

vasoconstriction

Question 32

Alpha 2 receptors in the nervous system can be in the

Answer 32

medulla
vagus nerve
locus coeruleus
spinal cord (dorsal horn)

Question 33

Alpha 2 receptors in the nervous system have the physiologic effect of

Answer 33

decreased SNS tone
increased PNS tone
sedation, hypnosis
analgesia
anti-shivering effect

Question 34

What is the alpha 2 vs. alpha 1 binding of clonidine?

Answer 34

200:1

Question 35

What is the alpha 2 vs. alpha 1 binding of dexmedetomidine?

Answer 35

1600:1

Question 36

Clonidine MOA

Answer 36

acts as an alpha 2 agonist at central presynaptic receptors inhibiting norepinephrine release causing vasodilation

Question 37

Abrupt discontinuation of clonidine may cause

Answer 37

rebound hypertension, tachycardia, and arrhythmia
tapered discontinuation is best

Question 38

Clonidine has been used for

Answer 38

diagnosis of pheochromocytoma
controlling opiate and nicotine withdrawal manifestations
treating hypertension

Question 39

Rapid administration of dexmedetomidine can stimulate the postsynaptic alpha-2 receptors in the

Answer 39

arterial and venous circulations leading to vasoconstriction and hypertension

Question 40

Which adrenergic agonist is NOT arrhythmogenic?

Answer 40

phenylephrine

Question 41

Which selective alpha-2 agonist is more highly protein-bond?

Answer 41

dexmedetomidine at 94%