Endogenous Catecholamines

Question 1

Epinephrine Class

Answer 1

Endogenous catecholamine, non-selective adrenergic agonist

Question 2

Epinephrine MOA

Answer 2

Direct alpha- and beta-adrenergic agonist, increased cAMP

Low doses (B2): vasodilation of skeletal muscle & ↓ SVR, bronchodilation, & ↓ histamine release

Moderate Doses (B1): ↑ HR & contractility

High doses (A1 &B): ↑ vasoconstriction = ↑ SBP, ↑CO

Question 3

Epinephrine Dosing (4)

Answer 3

Cardiac arrest, shock: 1 mg

Anaphylaxis: 100-500 mcg

Infusion: 2 – 20 mcg/min

Low dose infusion – beta agonism predominates

Medium dose infusion – equal beta and alpha agonism

High dose infusions – alpha agonism predominates

Mixed with local anesthetics to decrease systemic absorption 1:200,000 (5mcg/mL of epinephrine)

Question 4

Epinephrine Onset and DOA

Answer 4

Onset: 1 minute
Duration: 5 minutes

Question 5

Epinephrine Metabolism

Answer 5

MAO, COMT

Question 6

Epinephrine Excretion

Answer 6

Renally excreted

Question 7

Epinephrine Admin Considerations (3)

Answer 7

May cause tachycardia, arrythmias, angina, hypertension, decrease perfusion to splanchnic organs and uterus, and gangrene in digits

Avoid in peripheral nerve blocks

Caution in patients with CAD, hyperthyroidism and pheochromocytoma

Question 8

Norepinephrine Class

Answer 8

Endogenous catecholamine, adrenergic agonist

Question 9

Norepinephrine MOA

Answer 9

Endogenous direct acting catecholamine – agonizes A1, A2 & weak B1

Increases SVR by vasoconstricting arteries and veins via A1

Question 10

Norepinephrine Uses

Answer 10

First-line vasopressor for septic shock

Question 11

Epinephrine Uses

Answer 11

Cardiac arrest, anaphylaxis, shock states, used with LA

Question 12

Norepinephrine Dosing

Answer 12

Infusion: 1 – 20 mcg/min

Question 13

Norepinephrine Onset and DOA

Answer 13

Onset: 1 minute
DOA: 2 minutes

Question 14

Norepinephrine Metabolism

Answer 14

MAO, COMT

Question 15

Norepinephrine Excretion

Answer 15

Renally Excreted

Question 16

Norepinephrine Admin Considerations (3)

Answer 16

May cause bradycardia (baroreceptor reflex), hypertension, profound decrease perfusion to splanchnic organs and uterus

Avoid in peripheral nerve blocks

Caution in patients with hyperthyroidism, pheochromocytoma and without central IV access d/t extravasation

Question 17

Dopamine Class

Answer 17

endogenous nonselective adrenergic and dopaminergic agonist, direct and indirect acting

Question 18

Dopamine MOA

Answer 18

dopamine stimulates D receptors, β-receptors, and α-receptors in a dose-dependent manner because of differing receptor affinities

Question 19

Dopamine Uses

Answer 19

Shock
BP support
Increases U/O but does not improve renal function

Question 20

Dopamine Dosing

Answer 20

Dopaminergic receptors: 2 mcg/kg/min
β receptors: 2 to 5 mcg/kg/min
α receptors: greater than 10 mcg/kg/min

Question 21

Dopamine Onset and DOA

Answer 21

Onset: 2 minutes
DOA: 10 minutes

Question 22

Dopamine Metabolism

Answer 22

MAO and COMT

75% inactive and 25% NE

Question 23

Dopamine Excretion

Answer 23

Renally excreted

Question 24

Dopamine Admin Considerations (3)

Answer 24

Dopamine also inhibits aldosterone, resulting in an increase in sodium excretion and urine output.

Caution in patents on MAOI and TCA, tachycardia, arrythmias

r/f extravasation