title: Doxazosin suppresses the morning increase in blood pressure and sympathetic nervous activity in patients with essential hypertension.
abstract: To investigate the effects of doxazosin on blood pressure and sympathetic nervous activity, we analyzed the circadian variation of blood pressure and the power spectrum of R-R intervals using an ambulatory multibiomedical monitoring system (TM2425) in 10 untreated outpatients with essential hypertension. After a 2-wk placebo period (P-period), we administered 1 to 4 mg of doxazosin mesilate to the patients for 2 to 6 wk (T-period). We measured systolic and diastolic blood pressure (SBP, DBP), heart rate, R-R intervals, posture, and activity with the use of TM2425. Power spectral analysis of R-R intervals was used to calculate the ratio of low to high frequency components (LF/HF). The values were compared between the P-period and T-period. Although daytime blood pressure significantly decreased during the T-period (SBP, 148.1 +/- 5.9 vs. 130.3 +/- 4.4 mmHg; DBP, 92.3 +/- 3.2 vs. 83.6 +/- 2.6 mmHg, p < 0.01), nighttime DBP did not. The LF/HF of R-R intervals in the daytime (5.8 +/- 2.0 vs. 4.9 +/- 1.2, p < 0.01) and the morning rise in blood pressure also decreased significantly (SBP, 17.5 +/- 9.4 vs. 12.1 +/- 6.5 mmHg; DBP, 12.5 +/- 6.5 vs. 8.3 +/- 5.3 mmHg, p < 0.05). We conclude that doxazosin may suppress the morning rise in blood pressure in association with a decrease in sympathetic nervous activity.
authors.affiliation: Department of Cardiology, Nanasawa Rehabilitation Hospital, Atsugi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawano
authors.forename: O
authors.initials: O
authors.lastname: Tochikubo
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: E
authors.initials: E
authors.lastname: Miyajima
authors.forename: M
authors.initials: M
authors.lastname: Ishii
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D017292:Doxazosin / Q000627:therapeutic use*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology*
chemical_list: D000959:Antihypertensive Agents; D017292:Doxazosin