Endogenous Catecholamines Flashcards
Epinephrine Class
Endogenous catecholamine, non-selective adrenergic agonist
Epinephrine MOA
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
Epinephrine Dosing (4)
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)
Epinephrine Onset and DOA
Onset: 1 minute
Duration: 5 minutes
Epinephrine Metabolism
MAO, COMT
Epinephrine Excretion
Renally excreted
Epinephrine Admin Considerations (3)
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
Norepinephrine Class
Endogenous catecholamine, adrenergic agonist
Norepinephrine MOA
Endogenous direct acting catecholamine – agonizes A1, A2 & weak B1
Increases SVR by vasoconstricting arteries and veins via A1
Norepinephrine Uses
First-line vasopressor for septic shock
Epinephrine Uses
Cardiac arrest, anaphylaxis, shock states, used with LA
Norepinephrine Dosing
Infusion: 1 – 20 mcg/min
Norepinephrine Onset and DOA
Onset: 1 minute
DOA: 2 minutes
Norepinephrine Metabolism
MAO, COMT
Norepinephrine Excretion
Renally Excreted
Norepinephrine Admin Considerations (3)
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
Dopamine Class
endogenous nonselective adrenergic and dopaminergic agonist, direct and indirect acting
Dopamine MOA
dopamine stimulates D receptors, β-receptors, and α-receptors in a dose-dependent manner because of differing receptor affinities
Dopamine Uses
Shock
BP support
Increases U/O but does not improve renal function
Dopamine Dosing
Dopaminergic receptors: 2 mcg/kg/min
β receptors: 2 to 5 mcg/kg/min
α receptors: greater than 10 mcg/kg/min
Dopamine Onset and DOA
Onset: 2 minutes
DOA: 10 minutes
Dopamine Metabolism
MAO and COMT
75% inactive and 25% NE
Dopamine Excretion
Renally excreted
Dopamine Admin Considerations (3)
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
