Epinephrine is one of the most important ACLS drugs because it relaxes bronchial smooth muscle and shunts blood to the body's core ---improving ventilation and making CPR more effective.^[6][7] With this in mind the primary A-B-C-Ds (Airway, Breathing, Circulation, Defibrillation) for adult emergency cardiac care can be modified to A-B-C-D-E, stressing the importance of epinephrine.

But more of a good thing is not necessarily better. The class IIb higher dosing regimes for epinephrine currently accepted by the AHA may be harmful. The results of a recent evidence-based study finds that higher cumulative epinephrine doses are associated with negative neurologic outcomes in patients who survive resuscitation.^[8] After epinephrine the ACLS provider can consider the use of antiarrhythmic medications.