Norepinephrine and Epinephrine

Question 1

Epinephrine

Answer 1

Increases:

• -HR
• -SV
• -CO
• -arrhythmias
• -Coronary Blood flow
• -Systolic arteriole pressure
• -Mean arterial pressure
• -Mean pulmonary blood pressure

Widens Pulse pressure!!
(ESPECIALLY low dose given subcutaneously)

*at low doses, may DECREASE BP
(so on time curve, pressure goes up initially, but as drug concentration declines the pressure goes below normal!)

Question 2

Norepinephrine

Answer 2

Increases:

• -SV
• -arrhythmias
• -coronary blood flow
• -Systolic arteriole pressure
• -diastolic arteriole pressure
• -mean arteriole pressure
• -Mean pulmonary pressure

Question 3

Similarities

Answer 3

Increase:

• -SV
• *arrhythmias
• -Coronary blood flow
• -systolic arterial pressure
• -mean arterial and pulmonary pressures

Question 4

Differences

Answer 4

• -HR
• -CO

–Pulse pressure

Question 5

Why difference in HR and CO?

Answer 5

Parasympathetic tone predominates in the heart

NE affects mainly alpha receptors, causing more intense vasoconstriction than E and causing major increase in Mean arterial pressure, thus stimulating vagus

Increased BP–>vagus parasympathetic activation on heart, decreasing HR and CO

(If atropine given before NE, then increase in HR and CO)

E does not increase mean arterial pressure much, and thus doesn’t stimulate vagus

Question 6

Why difference in Pulse pressure?

Answer 6

NE works more intensely on alpha receptors, increasing both systolic and diastolic pressures

E works on both beta receptors especially. Systolic pressure increases greatly b/c of increased SV etc., but diastolic doesn’t increase or even goes down b/c doesn’t work as much on alpha and does activate strongly the beta-2 receptors, causing vasodilation.

Question 7

Epinephrine affects B1 receptors of…

Cardiac effects

Answer 7

SA node and AV node

not really ventricular tissue

Question 8

Epinephrine Vascular effects

Answer 8

Vasodilation:
–skeletal muscle

Vasoconstriction:

• -cutaneous
• -renal (so incr renin secretion & dec BF)

Increases:

• -pulmonary pressures (arteries and veins)
• -Coronary BF

Question 9

Epinephrine administration

Answer 9

IV, inhaled, IM, subcutaneous (allergies)

NOT oral

Question 10

Epinephrine adverse effects

Answer 10

Cerebral hemorrhage (esp w/ non-selective BB)

Ventricular arrhythmias

Angina

Question 11

Epinephrine utility

Answer 11

emergency relief of anaphylaxis

vasoconstrictor w/ local anasthetics

Restoring cardiac rhythm in pts w/ cardiac arrest