We have compared the effects of dexmedetomidine and propofol on endocrine, 
metabolic, inflammatory and cardiovascular responses in patients in the 
intensive care unit (ICU) after major surgery. Twenty patients who were expected 
to require 8 h of post-operative sedation and ventilation were allocated 
randomly to receive either an infusion of dexmedetomidine 0.2-2.5 microg kg(-1) 
h(-1) or propofol 1-3 mg kg(-1) h(-1). Arterial pressure, heart rate and 
sequential concentrations of circulating cortisol, adrenocorticotrophic hormone 
(ACTH), growth hormone, prolactin, insulin, glucose and interleukin 6 were 
measured. An ACTH stimulation test was performed in all patients who received 
dexmedetomidine. Heart rate was significantly lower in the dexmedetomidine 
patients. There were no differences in arterial pressure, cortisol, ACTH, 
prolactin and glucose concentrations between the two groups. A positive response 
to the ACTH stimulation test varied depending on the diagnostic criteria used. 
The insulin concentration was significantly lower in the dexmedetomidine group 
at 2 h (P=0.021), although this did not affect blood glucose concentrations. 
Growth hormone concentrations were significantly higher in 
dexmedetomidine-treated patients overall (P=0.036), but circulating 
concentrations remained in the physiological range. Interleukin 6 decreased in 
the dexmedetomidine group. We conclude that dexmedetomidine infusion does not 
inhibit adrenal steroidogenesis when used for short-term sedation after surgery.