Author Question: A nurse is teaching nursing students about the use of alpha-adrenergic antagonists. Which statement ... (Read 48 times)

faduma · **on:** Jul 23, 2018

A nurse is teaching nursing students about the use of alpha-adrenergic antagonists. Which statement by the student indicates the need for further teaching?

a. Alpha-adrenergic antagonists block alpha1 receptors on arterioles and veins.
b. Dilation of arterioles has a direct effect on arterial pressure.
c. Dilation of veins by alpha-adrenergic antagonists improves cardiac output.
d. Venous dilation by alpha-adrenergic antagonists indirectly lowers arterial pressure.

Question 2

Because they cause vasoconstriction, alpha1-adrenergic agonists are especially useful for:

a. extending the duration of local anesthetics.
b. producing mydriasis to facilitate ophthalmic examinations.
c. slowing the heart rate in tachycardic patients.
d. treating hypotension.

onowka · **Reply #1 on:** Jul 23, 2018

Answer to Question 1

ANS: C
Cardiac output is decreased as a result of the venous dilation caused by alpha-adrenergic antagonists. Alpha-adrenergic antagonists block alpha1 receptors on both arterioles and veins. When alpha1 receptors on arterioles are blocked by alpha-adrenergic antagonists, a direct effect on arterial pressure occurs. When alpha1 receptors on veins are blocked by alpha-adrenergic antagonists, an indirect effect on arterial pressure occurs.

Answer to Question 2

ANS: A
The vasoconstrictive effects of alpha1-adrenergic agonists, such as epinephrine, help delay absorption of a local anesthetic, prolonging the anesthetic's effects. These agents can increase blood pressure but are not the primary drugs used except in emergency situations. Alpha1 receptors in the radial muscles of the iris, not vasoconstriction, cause mydriasis. Reflex bradycardia is a side effect and not a clinical use of these agents.