Epinephrine

Question 1

What is the drug classification of Epi?

Answer 1

Endogenous catecholamine

• nonselective adrenergic agonist stimulating alpha (1&2) and beta (1&2) receptors
• receptor selectivity is dose dependent

Question 2

What are the uses/indications of Epinephrine?

Answer 2

• bronchospasm/ bronchial asthma
• Hypersensitivity rxn (allergic rxn)
• open-angle glaucoma
• Cardiac arrest, asystole
• Electromechanical dissociation
• V.Fib unresponsive to initial defibrillation
• Infusion to increase myocardial contractility
• also added to LAs to decrease systemic absorption and prolong DOA of the anesthetic

Question 3

What is the MOA of Epi (hint: tell me by the dosages used, which receptors are being activated)?

Answer 3

• Beta 2: 1-2mcg/min IV (redistribution of BF to skeletal muscle)
• Beta 1: 4-5mcg/min IV
• Alpha and Beta: 10-20mcg/min IV (vasoconstriction

Question 4

What is Epi the most potent activator of?

Answer 4

Alpha receptors!!!!!!!!

Question 5

What are the routes of Epi?

Answer 5

SQ or IV

Question 6

What is the onset of SQ and IV Epi?

Answer 6

SQ: 5-10 minutes
IV: 1-2 minutes

Question 7

What is the DOA of Epi?

Answer 7

5-10 minutes

Question 8

What is the standard bolus dose of Epi for resuscitation?

Answer 8

10mcg/kg IV (can start with 2-8mcg/kg)

-with single bolus dose CV effects dissipate after 1-5min

Question 9

What are the CV effects of Epi?

Answer 9

• major role is BP regulation
• a1: Vasoconstriction-> Increase BP, CVP, Cardiac work, SVR
• a2: negative feedback-> decrease BP
• B1: increased contractility, HR, CO
• B2: Peripheral vasodilation-> decrease BP
• skin, mucosa, hepatic, renal (a1)
• B2- skeletal muscle

Question 10

With moderate epi doses SBP tends to __________(B1, A1), and DBP tends to _________ (B2) and MAP _______ _____ _______

Answer 10

• increase
• decrease
• stay the same

Question 11

What are the cerebral effects of epi?

Answer 11

at clinically relevant doses, MINIMAL effects on vasoconstriction of arterioles in: Cerebral, Coronary, and Pulmonary vasculature

Question 12

What are the ocular effects of Epi?

Answer 12

• accommodation for far vision (a1-mydriasis)

- regulation of IOP (a1, a2: increase humoral flow; B1: increase production of aqueous humor)

Question 13

What are the respiratory effects of Epi?

Answer 13

BRONCHODILATION

• dilates smooth muscles of bronchial tree (B2)
• Decreased release of vasoactive mediators (histamine) in bronchial vasculature (B2)
• Reduce mucosal secretion (decongestion) (a1)

Question 14

What are the GI effects of Epi?

Answer 14

A2: decreased digestive secretions
a, B2: decreased peristalsis, direct smooth muscle relaxation
a1: decreased splanchnic BF (drastically reduced even if BP relatively normal)

Question 15

What are the GU effects of Epi?

Answer 15

a1-renal BF decreased; contraction of urethral sphincter
B1- increased renin release from kidney
B2- relaxation- decreases UO
a1-facilitates ejaculation
B2- relaxation: inhibits labor!

Question 16

What are the metabolic effects of Epi?

Answer 16

• Glycogenolysis: B2
• Lipolysis (B3)
• Inhibit insulin release (a2)

Question 17

What is the e 1/2t of Epi?

Answer 17

30 seconds

Question 18

How is epi metabolized and eliminated?

Answer 18

• biotransformation by enzyme catechol-O-methyltransferase in the liver and kidneys; and monoamine oxidase
• inactive metabolites eliminated in the urine

Question 19

What are the side effects of Epi?

Answer 19

• tachycardia
• hypertension
• life threatening arrhythmias
• HA, nervousness, tremor
• palpitations
• hyperglycemia
• hypokalemia
• increased IOP

Question 20

What are the contraindications to Epi?

Answer 20

• shock
• cardiac arrhythmias
• severe HTN
• labor
• CHF
• CAD
• pheochromocytoma

Question 21

What is the dose of EPI for hypotension?

Answer 21

2-8mcg/kg IV

Question 22

What is the continuous infusion dose of Epi?

Answer 22

1-20mcg/min