Adrenergic Receptors



Adrenergic receptors are located throughout the body and are effected by numerous pharmacologic substances as summarized below:

Drug alpha beta-1 beta-2 DA effects
epinephrine +++ +++ ++ none ++CO, -SVR (low dose), +-SVR (high dose)
norepinephrine +++ +++ none none ++SVR, +-CO
Dopamine

 

Low dose

Medium dose

High dose

 

 

0

+

++

 

 

+

++

+++

 

 

0

0

0

 

 

++

++

++

 

 

+CO, +SVR

+ CO

++SVR

Dobutamine 0/+ +++ ++ 0 +CO,-SVR
Isoproterenol 0 +++ ++ 0 +CO,-SVR
phenylephrine +++ 0 0 0 +/-Co, ++SVR

Location of adrenergic receptors

alpha – vascular walls and generally induce vasoconstriction
beta- 1 – heart and act as inotropic and chronotropic agents
beta -2 – blood vessels and induces vasodilation
DA receptors – coronary, mesenteric, renal, and cerebral vascular bed and cause vasodilation

Common Clinical Use

Norepinephrine (Levophed) – popular with surgeon intensivists in septic shock. Generally should not be used when patient is hypovolemic and vigorous fluid resuscitation with isotonic or hypertonic saline should be initiated before use

Epinephrine – second line agent after Levophed in septic shock. Used to rapidly interact with adrenergic receptors in codes and anaphylaxis.

Vasopressin – second or third line agent in septic shock. Is generally not titrated. Hard on the kidneys and also with coronary and mesenteric ischemia, limb and skin ishcemia, and pulmonary effects.

Dopamine – most common in cardiogenic shock. Can cause arrhythmias in sepsis

Dobutamine – most common in cardiogenic shock and heart transplants. Sometimes used by medical intensivists with Levophed in septic shock with depressed cardiac function

Isoproterenol – rarely used outside of the cardiac ICU and most often for torsades and bradycardia causing hypotension

 

 

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