Differential effects of an alpha 1-blocker (doxazosin) on diurnal blood pressure variation in dipper and non-dipper type hypertension.
A study was conducted to determine whether sympathetic nerve activity, one of the main regulators of blood pressure, is involved in high blood pressure in the night-time and morning. Twenty-seven untreated hypertensive subjects, in whom hypertension was diagnosed by ambulatory blood pressure (ABP) measurement, who showed a 24 h systolic ABP value over 140 mmHg and/or 24 h diastolic ABP over 90 mmHg were recruited. They also showed a night-time systolic ABP value of over 130 mmHg and/or a night-time diastolic ABP of over 80 mmHg. They were divided into two groups: "dippers (D)" whose night-time ambulatory blood pressure fell by more than 10% of the day-time blood pressure, and "non-dippers (ND)" in whom this phenomenon was absent. We examined the effect of a long-acting alpha 1-blocker (doxazosin) on diurnal blood pressure variation in these subjects with essential hypertension. Baseline casual blood pressure and 24 h systolic ABP were not significantly different between the two groups. However, both night-time and morning ABP in ND were higher than those in D. Administration of doxazosin (mean 73 +/- 13 (SE) d) significantly decreased casual blood pressure, and 24 h, day-time, night-time and morning systolic ABP in the whole cohort. When subjects were divided into D and ND, the day-time and morning systolic ABP decreased significantly after doxazosin treatment in both groups, whereas the night-time systolic ABP decreased significantly only in ND but not in D. These results suggest that sympathetic nerve activity involved in elevating blood pressure during the night may differ between D and ND.
Ebata
H
H
Department of Cardiology, Jichi Medical School, Tochigi, Japan.
Hojo
Y
Y
Ikeda
U
U
Ishida
H
H
Natsume
T
T
Shimada
K
K
D000317:Adrenergic alpha-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D017292:Doxazosin / Q000627:therapeutic use*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged
D000317:Adrenergic alpha-Antagonists; D017292:Doxazosin