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The effects of 4 weeks of placebo on clinic and on ambulatory blood pressure, measured non-invasively using the Remler M 2000 portometer, were studied in 46 hypertensive patients who were included in three consecutive double-blind randomized placebo-controlled trials with antihypertensive drugs. Placebo significantly reduced clinic blood pressure, but had no significant effect on ambulatory blood pressure. [ABSTRACT FROM AUTHOR]

The effect of guanfacine (2 mg once daily) on ambulatory blood pressure was studied with the Remler M 2000 recorder in 16 elderly hypertensive patients during a randomized, double-blind, placebo-controlled, balanced, cross-over study. Guanfacine significantly reduced heart rate and systolic and diastolic ambulatory blood pressure. The antihypertensive effect was maintained over the whole recording period. Systolic and diastolic blood pressure variability was not changed by guanfacine, neither when defined as standard deviation or variation coefficient of the mean, nor when defined as the range between the highest and lowest ambulatory blood pressure, suggesting that blood pressure variability is unrelated to sympathetic nervous system activity. [ABSTRACT FROM AUTHOR]

Chronic administration of nadolol has been reported to reduce blood pressure either without or with a concomitant fall of renal blood flow. We therefore studied the effects of nadolol 80 mg once daily on ambulatory blood pressure, renal and systemic haemodynamics in patients with mild to moderate essential hypertension. Ten patients took part in this randomized, double-blind, placebo-controlled, crossover study, each phase of which lasted 4 weeks. Nadolol significantly reduced ambulatory blood pressure and heart rate, but had no effect on blood pressure variability. Cardiac output was significantly reduced by nadolol and total peripheral resistance increased but without reaching statistical significance. Despite the fall in blood pressure and cardiac output, renal blood flow and glomerular filtration rate remained unchanged. The fraction of cardiac output reaching the kidneys rose significantly and renal vascular resistance was significantly reduced. Body weight, urinary sodium excretion and urine flow rate remained unchanged. We conclude that nadolol 80 mg once daily lowers ambulatory blood pressure in patients with mild to moderate hypertension without impairment of renal blood flow, indicating a redistribution of cardiac output to the kidneys. The mechanism of the renal vasodilator effect of nadolol remains to be determined. [ABSTRACT FROM AUTHOR]

A randomized, double-blind, placebo-controlled study was set up to study the effects of acute and chronic administration of carvedilol, a vasodilatory beta-blocker in essential hypertension. Acute administration of a single dose of 50 mg of carvedilol reduced systolic and diastolic blood pressure, without inducing reflex tachycardia. Renal blood flow was preserved; accordingly renal vascular resistance was significantly reduced. A significant reduction of glomerular filtration rate and filtration fraction was observed. Plasma renin activity (PRA) and plasma aldosterone were not changed. Chronic carvedilol treatment produced a significant fall in systolic and diastolic office and ambulatory blood pressure, heart rate, cardiac output, PRA and plasma aldosterone. Blood pressure variability was not changed. Renal blood flow, glomerular filtration rate and filtration fraction also remained unchanged; renal vascular resistance decreased significantly. It is concluded that carvedilol possesses definite antihypertensive and renal vasodilating properties, both acutely and after chronic treatment.

The effect of the converting enzyme inhibitor lisinopril on renal and cardiac hemodynamics was studied in patients with moderate to severe primary hypertension, in a multicenter, double-blind, randomized clinical trial comparing the antihypertensive effect of lisinopril (LIS) and nifedipine (NIF). After a 2 week placebo run-in period, 15 patients were randomized in a 2:1 ratio to receive either LIS (20-80 mg q.d., n = 10) or NIF (20-40 mg b.i.d., n = 5). LIS significantly reduced blood pressure (BP) without changing heart rate or cardiac output. LIS significantly increased renal blood flow; glomerular filtration rate (GFR) was not changed. It can be concluded that LIS is an effective antihypertensive agent with a favorable renal hemodynamic profile.