Sympatholytics

Question 1

What are the two major mechanisms by which alpha-

2 receptor agonism reduces blood pressure?

Answer 1

Stimulation of peripheral presynaptic alpha-2 receptors inhibits
catecholamine release, resulting in vasodilation. Stimulation of
central alpha-2 receptors reduces sympathetic outflow and
renin activity and produces sedation by decreasing circulating
catecholamine levels.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192.

Question 2

How are are clonidine, dexmedetomidine, and

methyldopa classified pharmacologically?

Answer 2

They are all three alpha-2 receptor agonists
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 287-288.

Question 3

Should clonidine be continued through the

perioperative period? Why or why not?

Answer 3

Clonidine should be continued throughout the perioperative
period because abrupt discontinuation can result in rebound
hypertension and tachycardia.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192.

Question 4

Does clonidine reduce blood pressure primarily by its
action on peripheral alpha-2 receptors or its action
on central alpha-2 receptors?

Answer 4

Agonism of the central alpha-2 receptors with subsequent
reduction in sympathetic outflow is the primary mechanism by
which it reduces blood pressure.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192

Question 5

What is the primary use of dexemedetomidine?

Answer 5

The primary indication for dexmedetomidine is short-term
sedation in critically ill patients.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192.

Question 6

What are the potential side effects of

dexmedetomidine?

Answer 6

Hypotension, bradycardia, oversedation, and delayed recovery.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 193.

Question 7

Does dexmedetomidine cause respiratory

depression?

Answer 7

Dexmedetomidine does not produce significant respiratory
depression.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192.

Question 8

What are the typical intended drug effects of

dexmedetomidine?

Answer 8

Dexmedetomidine provides anxiolysis, sedation, analgesia, and
sympatholysis.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 192.