SNS

Question 1

Why is epinephrine contraindicated in recent cocaine use?

Answer 1

Cocaine blocks catecholamine reuptake.
Epi would result in massive adrenergic excess.

Question 2

Why is epinephrine seldom used in thyroid storm?

Answer 2

Thyroid storm increases B-receptor sensitivity.
Epi may cause arrythmias.

Question 3

What is a concern with use of a non-selective Beta-blocker and epinephrine?

Answer 3

Beta-blocked = unopposed a1 stimulation.
Epi administration may cause severe hypertension (followed by reflex bradycardia).

Question 4

What is the mechanism that explains why epi is not the best choice for a patient on nonselective beta-blockers?

Answer 4

Epi stimulates:
B1 = Increased HR/contractility
B2 = vasodilation
a1 = vasoconstriction.

Beta blockade = primarily a1 stimulation.

Question 5

In the setting of beta-blocker overdose, what are the considerations with epinephrine administration?

Answer 5

BB overdose causes bradycardia, hypotension, decreased contractility.

Epi in these situations would not increase HR or contractility.

Question 6

Whyy is glucagon given in beta-blocker overdose?

Answer 6

Glucagon activates adenylate cyclase independent of beta receptors.
This increases cAMP which increases HR & contractility.