The bedtime administration of doxazosin controls morning hypertension and albuminuria in patients with type-2 diabetes: evaluation using home-based blood pressure measurements.

The control of high blood pressure (BP) after awakening in the morning (morning hypertension) as determined by home BP (HBP), as well as BP control throughout the day, may prevent diabetic vascular complications. We examined the effect of an alpha-adrenergic blocker (doxazosin) on BP measurements taken by HBP after awakening and during clinic visits (CBP) in 50 patients with type-2 diabetes and morning hypertension. We evaluated the urinary albumin excretion rate as an indicator of nephropathy. Doxazosin was taken orally once at bedtime for 1 to 3 months. The mean (+/- SD) dose was 2.9 +/- 2.1 mg/day (1 to 8 mg/day). The BP was measured monthly at the clinic during the day and at home after awakening in the morning. In this short-term trial (2.8 +/- 0.4 months), the systolic HBP decreased significantly from 164 +/- 17 mmHg before treatment to 146 +/- 19 mmHg after treatment, and the diastolic HBP decreased significantly from 85 +/- 14 mmHg before treatment to 80 +/- 9 mmHg after treatment. The systolic, but not the diastolic CBP, decreased significantly after treatment. There was no significant difference in the systolic or diastolic values between the HBP and the CBP after treatment. The percentage change in the systolic HBP after treatment was three times greater than for the systolic CBP. The median (interquartile) urinary albumin excretion rate decreased significantly (P < 0.001) from 62 (25-203) mg/g creatinine before treatment to 19 (9-76) mg/g creatinine after treatment. On multiple regression analysis, the decrease in the systolic HBP with treatment positively correlated with the reduction in urinary excretion of albumin. The control of morning hypertension reduced the albuminuria found in both untreated and treated hypertensive patients with type-2 diabetes. Bedtime administration of doxazosin appears to be safe and effective in reducing morning hypertension as measured by HBP. This finding also demonstrates that HBP taken in the morning has a stronger predictive power for the albuminuria level than does CBP.