August 15, 2025

Welcome again to UH EMSI’s Pharmacy Phriday CE offering. Over the past few weeks, we have focused on some of the medications administered in cardiac care algorithms. In this installment, we’ll review the 0.1 mg/ml concentration of epinephrine, the first-line medication administered IV or IO in cardiac arrest.  

Epinephrine is a catecholamine found naturally in the body that affects the sympathetic nervous system. It is an adrenergic (sympathomimetic) agent and cardiac stimulant that acts on both alpha and beta receptor sites. It is a mainstay in the management of cardiac arrest and impending arrest during anaphylactic shock. Cited in current American Heart Association (AHA) texts, early administration of epinephrine in cardiac arrest is associated with greater return of spontaneous circulation (ROSC).  

Epinephrine’s alpha effects cause vasoconstriction that improves perfusion pressure to the brain and heart. Its most prominent actions are on the beta receptors of the heart, vascular, and other smooth muscle. When given as an IV bolus, stimulation of the beta-1 adrenergic receptors in the heart results in a positive inotropic effect (increasing contractility), a positive chronotropic effect (increasing the heart rate), and a positive dromotropic effect (increasing the rate of conduction through the AV node).  

Epinephrine is provided in our UH drug boxes in various concentrations. Ensure you have the correct concentration and dose for proper treatment before administration. Remember, in this article, we are discussing the “cardiac” epinephrine, the concentration of 0.1 mg/ml (100 mcg/ml).  

Epinephrine in the concentration of 0.1 mg/ml is indicated for use by UH protocols in cases of cardiac arrest and impending arrest during anaphylaxis. Impending arrest in anaphylaxis is defined in our protocols as the lack of or weak, thready radial pulses, severe hypotension, decreased level of consciousness, and airway compromise. Dosages are indicated in the following table: 

Until the next installment, stay safe! 

Sincerely, 

The UH EMS-I Team 

University Hospitals