Can epinephrine (epi) infusion cause vasoconstriction?

From the Guidelines

Epinephrine infusion can cause vasoconstriction, particularly at higher doses (>0.3 mcg/kg per minute), due to its action on alpha-adrenergic receptors. This is supported by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care, which states that low-dose infusions of epinephrine (<0.3 mcg/kg per minute) produce β-adrenergic actions, while higher-dose infusions cause α-adrenergic vasoconstriction 1. The dose-dependent effect of epinephrine makes it useful in treating conditions like anaphylaxis and shock, where vasoconstriction helps maintain blood pressure and vital organ perfusion. Key points to consider include:

• Low-dose epinephrine infusions (<0.3 mcg/kg per minute) generally produce β-adrenergic actions, such as tachycardia, potent inotropy, and decreased systemic vascular resistance
• Higher-dose infusions (>0.3 mcg/kg per minute) cause α-adrenergic vasoconstriction, which can increase peripheral vascular resistance and elevate blood pressure
• There is great interpatient variability in response to epinephrine, so the drug should be titrated to the desired effect 1.

From the FDA Drug Label

5.2 Pulmonary Edema Epinephrine increases cardiac output and causes peripheral vasoconstriction, which may result in pulmonary edema. 5.4 Extravasation and Tissue Necrosis with Intravenous Infusion ... Blanching along the course of the infused vein, sometimes without obvious extravasation, may be attributed to vasa vasorum constriction with increased permeability of the vein wall, permitting some leakage. 5.5 Renal Impairment Epinephrine constricts renal blood vessels, which may result in oliguria or renal impairment.

Yes, epinephrine (epi) infusion can cause vasoconstriction. This is evident from the drug label, which states that epinephrine causes peripheral vasoconstriction, constricts renal blood vessels, and may cause vasa vasorum constriction 2.

From the Research

Vasoconstriction Effects of Epinephrine Infusion

• Epinephrine infusion can cause vasoconstriction, as evidenced by studies that have investigated its effects on the vascular system 3, 4, 5.
• The study by 1987 found that epinephrine infusion increased blood pressure and reservoir volume, and decreased systemic vascular compliance due to venoconstriction 3.
• Another study published in 2016 found that the vasoconstriction time of epinephrine in the scalp correlated positively with concentration, and the duration of vasoconstriction was longer at certain injection sites 4.
• A study from 1984 found that adrenaline (epinephrine) induces vasoconstriction through post-junctional alpha 2 adrenoceptors, and this response is enhanced in patients with essential hypertension 5.
• Other studies have compared the effects of epinephrine with other vasopressors, such as norepinephrine and phenylephrine, on microcirculatory blood flow in the gastrointestinal tract in sepsis 6, 7.
• The study by 2006 found that epinephrine and norepinephrine caused a significant reduction in superior mesenteric artery flow and in microcirculatory blood flow in the jejunal mucosa and pancreas, while phenylephrine had no effects on systemic, regional, or microcirculatory flow except for a 30% increase in jejunal muscularis flow 7.

Mechanisms of Vasoconstriction

• The mechanisms of vasoconstriction induced by epinephrine infusion are complex and involve the activation of alpha 2 adrenoceptors 5.
• The study by 1987 found that epinephrine caused redistribution of blood flow away from the compartment with the longest time constant by constricting the arterioles leading to it 3.
• The study by 2016 found that the duration of vasoconstriction was shorter at certain injection sites, suggesting that the effects of epinephrine may vary depending on the location and concentration of administration 4.

Clinical Implications

• The findings of these studies have important implications for the clinical use of epinephrine infusion, particularly in patients with sepsis or essential hypertension 3, 5, 6, 7.
• The study by 2006 suggests that epinephrine and norepinephrine may divert blood flow away from the mesenteric circulation and decrease microcirculatory blood flow in the jejunal mucosa and pancreas, which could have negative consequences for patients with sepsis 7.
• Further research is needed to fully understand the effects of epinephrine infusion on the vascular system and to optimize its use in clinical practice 3, 4, 5, 6, 7.