Pregnanolone: a new steroid intravenous anaesthetic. 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.
Powell
H
H
Department of Anaesthetics, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Morgan
M
M
Sear
J W
JW
D000328:Adult; D000771:Anesthesia, Intravenous; D001049:Apnea / Q000139:chemically induced; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011280:Pregnanolone / Q000008:administration & dosage* / Q000009:adverse effects; D012018:Reflex / Q000187:drug effects
D011280:Pregnanolone