Phenylephrine (Neo)

Question 1

Phenylephrine MOA: Phenylephrine primarily targets ___ receptors. Occupancy by agonists at alpha-1 increase in synthesis of 2nd messengers: such as ___ which results in an increase of ___ release from the __. This results in vasoconstriction of ____ ___ ___.

___ constriction > ___ constriction.

Answer 1

Phenylephrine primarily targets ALPHA 1 receptors. Occupancy by agonists at alpha-1 increase synthesis of 2nd messengers: IP3 which increases calcium release from the SR. This results in vasoconstriction of vascular smooth muscle.

VENOUS constriction > arterial constriction.

Question 2

PP: The typical dose range for Phenylephrine (Neo-synephrine) when administered IV is __ to __ mcg.

TexWes Ref: __ mcg.

Answer 2

PP: 50-100 mcg

Tex Wes Ref: 100 mcg

Question 3

What is the concentration of Phenylephrine (Neo-synephrine) in its supplied vial?

Answer 3

10 mg/mL

Question 4

On hand you have 10 mg/mL of phenylephrine, how do you get to a concentration of 100 mcg/mL?

Answer 4

Dilute phenylephrine (10 mg/mL) in a 100 mL bag of NS to get a concentration of 100 mcg/mL.

Question 5

If you dilute 10 mg/mL of phenylephrine into a 250 mL bag of NS, what is your new concentration and how many mL would you need to give in order to administer 100 mcg?

Answer 5

1. 10 mg/250 mL = 0.04 mg/mL or 40 mcg/mL
2. 100 mcg/40 mcg per mL = 2.5 mL

Question 6

Harris carries phenylephrine syringes with a concentration of __ mg/10 mL or __mcg/mL.

Answer 6

1 mg/10 mL (1000mcg/10mL)
OR
100 mcg per mL.

Question 7

A push dose of phenylephrine has a duration of action of about __ to __ minutes.

Answer 7

10 to 20 minutes