[Effect of doxazosin on postural changes in blood pressure using a multibiomedical recorder]

To investigate the effect of doxazosin on orthostatic blood pressure changes with daily activity, the relationship among blood pressure, physical position and physical activities using an ambulatory multibiomedical monitoring system(TM2425) were studied. The subjects were 22 patients with essential hypertension(EHT group), 23 patients with diabetic mellitus(DM group) and 17 healthy volunteers for the control. Patients were administered doxazosin at 2-8 mg/day for 0.5 month to 12 months. Twenty-four-hour blood pressure, posture and activity were monitored. Systolic blood pressure was higher in the standing position than that in the sitting position in the control group, but there were no differences between these values in the EHT group and DM groups. During the awake, sleep, and standing periods, doxazosin significantly decreased blood pressure in the EHT group; however, it significantly decreased only the standing systolic blood pressure in the DM group. Absolute changes in blood pressure after the administration of doxazosin were not significantly different between the standing and sitting periods in each group. These findings suggest that doxazosin decreases the blood pressure of both patients with essential hypertension and patients with diabetic mellitus without an excessive decrease in standing blood pressure.