Epinephrine is a commonly used drug in intensive care units.
Involved Receptors
Epinephrine acts on the alpha-1, beta-1, and beta-2 receptors
Actions of Epinephrine
Cardiovascular effects
1) increased heart rate and force of contraction
2) increased cardiac output
3) increased systolic pressure but if low doses are administered may cause decrease in diastolic blood pressure and increased blood flow through skeletal muscle (beta-2 effect)
4) vasoconstriction increased at higher doses because of alpha-1 effect
5) requires adequate fluid resuscitation to avoid ischemic limbs – generally surgeon intensivists are more willing to give larger volumes of isotonic fluid or hypertonic saline comcomitantly with epinephrine to avoid ischemic effects as opposed to medical intensivists.
Respiratory effects
6) epinenephrine causes increased relaxation of bronchial smooth muscle
Other
7) dilation of pupils (mydriasis)
8) increased serum glucose secondary to increased glycogenolysis
Side effects
1) limb ischemia which can largely be avoided if aggressive fluid resuscitation is undertaken
2) ventricular arrhythmias
3) hypertension
Preparation
IV – 1:10,000 or 1 mg in 10 ml
IM/SC – 1:1000 or 1 mg in 1 ml
Indications
1) sepsis
2) cardiac arrest
3) anaphylactic shock
4) acute severe asthma attack
5) cardiac arrest per ACLS protocol
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