Alpha-1 Selective Agonists

Question 1

Phenylephrine is a potent, direct acting ___ adrenergic agonist

Answer 1

alpha-1

Question 2

How does phenylephrine affect systolic and diastolic blood pressure?

Answer 2

Increases

Question 3

How does phenylephrine affect heart rate? Why?

Answer 3

Decrease (reflexive bradycardia)

Question 4

How does phenylephrine affect vasculature and blood flow?

Answer 4

Decreases blood flow, causes vasoconstriction

Question 5

What is the role of the compensatory autonomic baroreflex response in phenylephrine?

Answer 5

The response blunts the a1 agonist BP effects. Therefore: as HR increases, BP decreases and vice versa.

Question 6

Therapeutic uses of phenylephrine? (3)

Answer 6

1) Hypotension (orthostatic/shock)
2) Nasal decongestant
3) Ophthalmic agent