Phenylephrine (Alpha 1 Agonist)

Question 1

What is the appropriate intravenous push (IVP) dose range for Phenylephrine?

A. 10-20 mcg
B. 50-100 mcg
C. 200-300 mcg
D. 5-10 mcg

Answer 1

B. 50-100 mcg

Question 2

What is the concentration of a premade stick of Phenylephrine for IV push administration?

A. 10 mcg/mL
B. 20 mcg/mL
C. 100 mcg/mL
D. 200 mcg/mL

Answer 2

C. 100 mcg/mL

Question 2

What is the correct infusion dose range for Phenylephrine?

A. 1-20 mcg/min
B. 50-100 mcg/min
C. 100-500 mcg/min
D. 10-200 mcg/min

Answer 2

Answer: D. 10-200 mcg/min

Question 3

How is Phenylephrine diluted for continuous infusion?

A. 10 mg in 100 mL
B. 10 mg in 500 mL
C. 10 mg in 250 mL
D. 10 mg in 50 mL

Answer 3

C. 10 mg in 250 mL (resulting in 40 mcg/mL)

Question 4

What is the duration of action (DOA) for IV Phenylephrine?

A. Less than 5 minutes
B. 10-20 minutes
C. 20-30 minutes
D. 30-60 minutes

Answer 4

A. Less than 5 minutes

Question 4

What is the onset of action for IV Phenylephrine?

A. Less than 30 seconds
B. Less than 1 minute
C. 2-3 minutes
D. 5-10 minutes

Answer 4

Answer: B. Less than 1 minute

Question 5

Which of the following hemodynamic effects is caused by Phenylephrine?

A. Increased heart rate (HR)
B. Decreased systemic vascular resistance (SVR)
C. Increased cardiac output (CO)
D. Reflex bradycardia

Answer 5

D. Reflex bradycardia (baroreceptor mediated)

Question 6

What is the primary mechanism of action (MOA) of Phenylephrine?

A. Direct Beta-1 agonist
B. Indirect sympathomimetic
C. Direct Alpha-1 agonist
D. Non-selective Beta blocker

Answer 6

C. Direct Alpha-1 agonist

MOA: Direct Sympathomimetic (alpha 1 adrenergic agonist). Constriction of both arterial and venous blood vessels increases afterload by increasing SVR.

Question 7

alpha +++,
beta1 zero,
beta2 +,
CO -,
HR -,
Dysrhythmias N/A

Question 8

In which situation should caution be exercised when administering Phenylephrine?

A. Hypertensive crisis
B. Cardiogenic shock or heart failure (HF)
C. Aortic stenosis
D. Hypotension during spinal anesthesia

Answer 8

B. Cardiogenic shock or heart failure (HF)

Not useful in HF over Levo

Question 8

Phenylephrine is especially useful in which of the following conditions?

A. Cardiogenic shock
B. Congestive heart failure (CHF)
C. Aortic stenosis
D. Hypovolemic shock

Answer 8

C. Aortic stenosis
Useful in aortic stenosis (↑CPP)