Background and Goal of Study: Hypotension commonly accompanies anaesthesia, and intravenous ephedrine and etilefrine are widely used to correct hypotension during anaesthesia. We have noticed that these drugs decrease systemic vascular resistance (SVR) transiently just after bolus intravenous administration. The goal of the present study was to investigate whether bolus administration of these drugs decrease SVR just after intravenous administration, and also to evaluate potential differences in very acute haemodynamics between intravenous ephedrine and etilefrine in man, which has never been reported.
Materials and Methods: Patients were randomised to receive either ephedrine or etilefrine intravenously. After epidural anaesthesia was performed, and 30 minutes after induction of general anaesthesia, if a decrease in systolic blood pressure (SAP) of >20% compared with that just before epidural anaesthesia or a SAP of <100 mmHg occurred, the patient was chosen as a subject, and baseline haemodynamic values were recorded. These values were recorded again for 5 minutes after bolus injection of ephedrine 10 mg or etilefrine 2 mg (doses are considered equipotent).
Results: 40 patients were examined. Patient characteristics were comparable in both groups. After ephedrine bolus injection, systemic vascular resistance (SVR) decreased significantly at the 1-min time point compared with baseline values. After etilefrine bolus injection, SVR decreased significantly at the 0.5- to 2-min time points compared with baseline values. There were significant decreases in SVV at the 2- to 5-min time points and in SVR at the 0.5- to 2-min time points compared with baseline values. SVR at the 0.5- to 1-min time points was lower in the etilefrine versus the ephedrine group.
Conclusions: Both drugs decreased SVR transiently after intravenous injection, but etilefrine decreased SVR much more than ephedrine, indicating that more vasodilation occurs after the injection of etilefrine than after ephedrine. Thus, it is important to recognise the characteristics of these drugs.

Bolus administration of ephedrine and etilefrine induces transient vasodilation just after injection in man