Recent studies question whether or not epinephrine provides any overall benefit for human patients.
A randomised controlled trial shows that epinephrine for out-of-hospital cardiac arrest will increase the rate of pulse return, however, it doesn't considerably alter longer-term survival. Large controlled studies suggest that, despite increases in pulse return, epinephrine reduces long-term survival (to hospital discharge.) The damaging effects were greatest in patients found in ventricular fibrillation. Laboratory information suggest that harmful epinephrine-induced reductions in microvascular blood flow throughout the arrest, and in the post-arrest patient, might offset the useful effects epinephrine-induced increase in blood pressure throughout CPR.