PREGNANOLONE - A NEW STEROID INTRAVENOUS ANESTHETIC - DOSE-FINDING STUDY

The intravenous steroid anaesthetic pregnanolone has been investigated as an induction agent in 60 fit adults premedicated with morphine and atropine. The drug was given in a stepwise fashion starting with 0.5 mg.kg−1; following a successful induction, the next patient received 15% less, while the subsequent patient received 15% more if anaesthesia was not achieved. Taking loss of eyelash reflex as the end point, 31 patients were satisfactorily induced; the AD50 in these patients was 0.44 mg.kg−1 (95% CI 0.41–0.47). A further 23 patients were induced satisfactorily as assessed by cessation of counting. Induction was trouble free with minimal changes in heart rate and arterial blood pressure, a low incidence of apnoea and few involuntary movements; pain on injection was not a feature. Loss of eyelash reflex is not a good end point for assessment of loss of consciousness following pregnanolone. Copyright © 1992, Wiley Blackwell. All rights reserved