Effect of Administration and Withdrawal of Doxazosin on Ambulatory Blood Pressure in Patients with Essential Hypertension

The effect of both administration and withdrawal of doxazosin on patients with essential hypertension was evaluated by twenty-four-hour ambulatory blood pressure (BP) monitoring. Six hypertensive men were treated with doxazosin starting at 1 mg/day, and the dosage was titrated at weekly intervals up to a maximum of 8 mg/day. The twenty-four-hour BP profile was monitored noninvasively before treatment, in the fourth week of treatment, and on days 2 and 7 after the discontinuation of doxazosin. The average twenty-four-hour systolic and diastolic BPs (SBP and DBP) were lowered by doxazosin treatment and returned to the pretreatment levels within two days of doxazosin withdrawal. Doxazosin treatment produced a significant decrease in the daytime SBP and DBP but not in the nighttime BP values. The daytime BP decrease was no longer detected on days 2 and 7 after drug withdrawal. The twenty-four-hour pulse rate was not influenced by either doxazosin administration or discontinuation. The plasma norepinephrine co...