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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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 concentration and plasma renin activity were increased by doxazosin treatment and were decreased by drug withdrawal. There was no rebound hypertension following doxazosin withdrawal. Thus, the present study using twenty-four-hour BP monitoring showed that doxazosin treatment reduced the daytime BP in patients with essential hypertension and that this reduction was abolished within two days after doxazosin discontinuation.
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PMID:Effect of administration and withdrawal of doxazosin on ambulatory blood pressure in patients with essential hypertension. 781 52

Doxazosin, a once daily alpha-blocking drug has been demonstrated to reduce both BP and hyperlipidaemia, related risk factors for premature vascular disease. This study was designed to see if a low fat diet altered the favourable effect of doxazosin on blood lipids in adults with mild to moderate hypertension and mild to moderate hypercholesterolaemia (5.6-8.0 mmol/l). Following a six week period on a low fat diet, patients were randomly allocated to additional doxazosin (2-8 mg/day) or enalapril (5-20 mg/day) treatment for a further 10 weeks. Forty-four of 55 subjects completed the study. A low fat diet reduced mean body weight by 2 kg without significantly altering blood lipids (total and HDL cholesterol, triglycerides). Doxazosin (4.5 +/- 2.9 mg/day) and enalapril (12.5 +/- 6.5 mg/day) produced a comparable lowering of sitting and standing BP at all visits and also produced similar 24h BP control. The expected increase in HDL cholesterol concentration previously noted in this patient population in association with doxazosin treatment was not detected suggesting that the low cholesterol-high carbohydrate diet, at least acutely, attenuates this potentially beneficial effect on plasma lipids. In summary, doxazosin has a comparable tolerability and BP lowering ability to enalapril. However, its ability to increase HDL cholesterol may be reduced in patients on low fat diets.
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PMID:Combined effect of a low fat diet and doxazosin on blood pressure control and blood lipids. Hunter Hypertension Research Group. 788 89

Hypertension often exists as part of a syndrome of cardiovascular, neuroendocrine and metabolic abnormalities. While antihypertensive pharmacotherapy has reduced the rates of stroke, congestive heart failure and renal failure, a disappointing benefit in terms of the reduction in coronary heart disease (CHD) mortality has been seen as a result of the adverse effects of some of the traditional antihypertensive agents on serum lipids and other factors. Doxazosin, a selective alpha 1-adrenoceptor inhibitor, is an effective antihypertensive agent with beneficial effects on an array of atherogenic risk factors. Treatment with doxazosin can lower blood pressure, reduce the levels of atherogenic lipids, increase the levels of cardioprotective lipids, reduce hyperinsulinaemia, insulin resistance and glucose intolerance, increase fibrinolysis, inhibit platelet aggregation, attenuate the adverse haemodynamic and haemostatic effects of smoking, and regress cardiac and smooth muscle hypertrophy. This unique combination of risk factor modifications should produce a reduction in CHD events.
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PMID:Effects of doxazosin on coronary heart disease risk factors in the hypertensive patient. 804 19

To examine the neural effects of antihypertensive drugs on renal blood flow, we measured blood flow and renal sympathetic nerve activity simultaneously in conscious spontaneously hypertensive rats aged 13 to 15 weeks. One to two days after surgery, intravenous administration of manidipine (calcium antagonist, n = 10), doxazosin (alpha 1-adrenergic receptor antagonist, n = 9), and clonidine (n = 7) lowered mean arterial pressure by at least 20% from baseline levels. Manidipine initiated a reduction of renal blood flow when mean pressure decreased by 20 +/- 2 mm Hg. At the maximal decrease in renal blood flow (mean pressure, -33 +/- 2 mm Hg), percent decrease in flow (-27 +/- 2%) significantly correlated with percent increase in renal nerve activity (+205 +/- 40%, r = -.878). Doxazosin began to decrease renal blood flow at a level of arterial pressure similar to that in manidipine treatment, whereas the maximal decrease in flow (-19 +/- 2%; mean pressure, -33 +/- 2 mm Hg; nerve activity, +225 +/- 44%) was significantly less than that in manidipine treatment. Although clonidine decreased arterial pressure and renal nerve activity, renal blood flow did not decrease even at the maximal decrease in mean pressure of 29 +/- 1 mm Hg. The addition of clonidine to manidipine treatment suppressed reflexly enhanced renal nerve activity and restored blood flow to the pretreatment level despite pronounced hypotension. These results clearly demonstrate that antihypertensive drugs with blocking action on renal nerve activity are capable of maintaining renal blood flow and that those associated with reflex-induced enhancement of nerve activity exert deteriorating effects on renal blood flow. Furthermore, a decrease in renal blood flow induced by calcium antagonists is mainly attributed to reflexly enhanced renal nerve activity.
Hypertension 1994 Jan
PMID:Neural effects on renal blood flow during acute hypotension vary with antihypertensive drugs. 828 84

4,260 patients were included in an open surveillance study simultaneously with the introduction of doxazosin for treatment of essential hypertension in Norway. The main aim of the study was to systematically collect information on side effects and events in patients being treated with a new drug. The effect on blood pressure, heart rate and lipids was also recorded. The study lasted for one year. 21 deaths were reported. 53% of the patients reported side effects and/or events. The frequency of side effects was particularly high during the first month of treatment. No new types of side effects were found. The initial higher frequency of reported side effects referred to all organ systems, and was also of the same magnitude in the different systems. A relation was found between certain cardiac side effects and/or events and cessation of previous medication upon starting treatment with doxazosin. The study shows that certain safety precautions should be observed in patients with coronary heart disease and heart failure. In three patients, doxazosin should be used only in combination with more specific treatment. Special caution should be observed when changing the specific basic treatment. Doxazosin had a very favourable antihypertensive effect. A drop in cholesterol and triglycerides was observed, as expected. The HDL-cholesterol value declined, which was unexpected. The results are difficult to interpret, owing to lack of a control group. On the other hand, the study shows how high blood pressure is being treated with drugs in ordinary practice. The authors discuss the methodology of surveillance studies.
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PMID:[Doxazosin (Carduran)--a research survey]. 790 29

Doxazosin was administered to rabbits fed diets enriched in cholesterol and peanut oil for 7.5 or 12 weeks, in 2 separate experiments. Doxazosin suppressed the accumulation of cholesterol and formation of atherosclerotic plaques in the aortas of treated rabbits and prevented a diet-induced increase in aortic collagen and wall mass. Doxazosin was more effective in the thoracic and abdominal segments of the aorta than in the aortic arch. Pharmacokinetic analysis indicated that treated rabbits were exposed to concentrations of doxazosin, integrated over 24 h, which were consistent with the therapeutic range of doxazosin measured in patients treated for hypertension. Doxazosin did not alter serum levels of cholesterol or triglycerides, nor were there any consistent effects on glucose, free fatty acid or ketone levels. Hypotheses of the mechanism of action of doxazosin are discussed, including the possible involvement of alpha 1-adrenergic receptors in recruitment of smooth muscle cells by subintimal macrophages and nonadrenergic mechanisms of inhibition of lipid infiltration.
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PMID:Effects of doxazosin on atherosclerosis in cholesterol-fed rabbits. 850 48

The Hypertension and Lipid Trial (HALT) was undertaken to assess the efficacy and safety of doxazosin, a selective alpha 1- adrenergic blocker, in patients with hypertension in a clinical practice setting. The effects of doxazosin on office blood pressure, changes in lipid profiles, and theoretic coronary disease risk were studied. In an open, noncomparative, multicenter trial, 851 patients were studied for a maximum of 16 weeks. Doxazosin significantly reduced mean sitting systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 15.2/12.5 mm Hg and standing SBP and DBP by 16.1/12.7 mm Hg in the total study population (n = 807; p = 0.0001), with no significant effect on heart rate. Mean total cholesterol levels were significantly reduced by 2.7%, low-density lipoprotein cholesterol levels by 2.4%, and mean triglyceride levels by 3.4% (all p values < 0.05). High-density lipoprotein (HDL) cholesterol levels were essentially unchanged. The mean ratio of total to HDL cholesterol was significantly reduced (p < 0.05). Mean predicted 5-year coronary disease risk was significantly reduced with doxazosin therapy by 14.7% in previously untreated patients (p < 0.0001) and by 1.7% in patients who were previously receiving antihypertensive therapy (p < 0.05). The drug was well tolerated. This study demonstrates that antihypertensive therapy with doxazosin can favorably affect coronary disease risk factors and reduce predicted coronary disease risk.
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PMID:Principal results of the Hypertension and Lipid Trial (HALT): a multicenter study of doxazosin in patients with hypertension. 861 18

We examined whether blood pressure reduction or good glycemic control equally lower albuminuria by preventing glomerular loss of heparan sulfate and progression of glomerulosclerosis in streptozotocin-induced diabetic rats. We used doxazosin, and alpha 1-adrenergic blocker, to lower systemic blood pressure, and good glycemic control was achieved by insulin treatment. Rats were killed after 20 weeks of treatment. Doxazosin significantly lowered systolic pressure in diabetic rats; however, it had no effect in normal rats. Good glycemic control also lowered systolic pressure. In diabetic rats with good glycemic control, doxazosin had an additive effect on blood pressure. Glomerular heparan sulfate synthesis was significantly lower and urinary albumin excretion higher in diabetic than in normal rats. Both doxazosin treatment and good glycemic control normalized these abnormalities in diabetic rats. Insulin normalized plasma glucose and glycosylated HbA1 concentrations in diabetic rats, as did doxazosin. Significant increases in mesangial area and glomeruloscelerosis were observed in diabetic rats. Only good glycemic control normalized these pathological changes in all diabetic rats. Two-way factorial ANOVA showed an interaction between the effects of doxazosin and insulin on systolic pressure and plasma glucose. The data show that after 20 weeks of doxazosin treatment, albuminuria was reduced by 80%; however, this treatment had no significant effect on mesangial expansion or progression to glomerulosclerosis. Conversely, good glycemic control prevented all three of the preceding sequelae.
Hypertension 1996 May
PMID:Doxazosin prevents proteinuria and glomerular loss of heparan sulfate in diabetic rats. 862 Dec 4

Doxazosin, a selective alpha 1-adrenoceptor antagonist, is an established first-line antihypertensive agent that is being introduced for the management of benign prostatic hyperplasia. Hypertension and benign prostatic hyperplasia are linked by the sympathetic nervous system, which has an aetiologic role in both conditions. The alpha 1-adrenoceptor is a mediator of increased tension, both in vascular and prostatic smooth muscle. Studies have shown that doxazosin, through its balanced action on alpha 1-adrenoceptor subtypes, reduces blood pressure and improves other risk factors for coronary heart disease, such as lipid profile, insulin sensitivity, left ventricular hypertrophy, platelet aggregation and fibrinolysis. Data are now accumulating to show that doxazosin improves urinary flow rates and symptoms in patients with benign prostatic hyperplasia. These effects have been demonstrated in controlled clinical studies, within weeks, and long term. Since hypertension and benign prostatic hyperplasia are widespread and often undiagnosed in the community, particularly with increasing age, doxazosin may be a particularly appropriate therapy for the considerable number of older men with both conditions.
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PMID:Doxazosin: a new approach to hypertension and benign prostatic hyperplasia. 873 35

Doxazosin, an alfa-1 adrenoceptor antagonist, was compared with nitrendipine, a calcium antagonist, to evaluate their efficacy and safety in 61 patients with mild to moderate hypertension. 31 patients were assigned randomly to receive 1-16 mg of doxazosin and 30 patients were assigned to 10-20 mg of nitrendipine during 14 weeks (10 weeks of titration and 4 weeks of maintenance). Mean final dose was 6.1 mg for doxazosin and 15.6 mg for nitrendipine. Both treatments reduced supine and standing diastolic and systolic blood pressure (p < 0.01 for all comparisons). 22 patients in the doxazosin group (78.6%) and 18 in the nitrendipine group (78.3%) were considered therapy successes. There were not clinically significant changes in laboratory tests for both groups. Global assessment of adverse events was similar for both treatments (46.7% for doxazosin and 44.8% for nitrendipine), although patients treated with nitrendipine presented facial rush (20%) against none of the doxazosin group (p < 0.05). Withdrawals due to adverse events were higher in the nitrendipine group than in the doxazosin one (20.7% versus 6.7%, p = 0.14). The results of this study confirms that both antihypertensives reduced blood pressure in patients with mild to moderate hypertension. Furthermore, doxazosin treatment demonstrates a fewer number of withdrawals caused by adverse events.
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PMID:[Randomized, comparative study to evaluate efficacy and safety of doxazosin versus nitrendipine in the treatment of mild to moderate hypertension]. 909 Oct 27


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