Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085580 (essential hypertension)
14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since it is not known for certain which alpha-adrenergic receptors mediate renal vasoconstriction in human essential hypertension, we infused either doxazosin (n = 7) or yohimbine (n = 7) into the renal arteries of hypertensive subjects immediately prior to diagnostic angiography. Both agents caused an increment in renal blood flow as assessed with the xenon-washout technique. Doxazosin increased renal flow from 342 +/- 36 to 360 +/- 55 ml/min per 100 g (0.05 less than p less than 0.10). Yohimbine enhanced flow from 380 +/- 41 to 485 +/- 63 ml/min per 100 g (p less than 0.01). The effect of yohimbine was significantly greater than that of doxazosin. In a control group (n = 7) receiving only saline, no changes in renal blood flow occurred. Doxazosin enhanced renin secretion in the kidney by 10 +/- 4% over levels in controls (0.05 less than p less than 0.10), whereas yohimbine increased renin release by 80 +/- 23% (p less than 0.01). The latter increase was apparently not due to alterations in flow alone, since the arteriovenous gradient for renin also widened. We conclude that in resting conditions, neurogenic vascular tone in the kidney depends mainly upon activation of alpha 2-adrenergic receptors. Moreover, these receptors exert a tonic inhibitory influence on renin release.
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PMID:Role of alpha 1- and alpha 2-adrenergic receptors in the human hypertensive kidney. 288 75

Doxazosin is a long-acting selective alpha 1-adrenoceptor antagonist structurally related to prazosin. Like prazosin, doxazosin exerts its antihypertensive effect by reducing total peripheral resistance by selective postsynaptic alpha 1-blockade, without reducing cardiac output, and similarly, doxazosin appears to have a negligible effect on heart rate. Doxazosin differs from prazosin in that its long half-life enables once-a-day oral administration. Doxazosin significantly lowers both standing and supine blood pressure and appears to maintain this antihypertensive effect over a 24-hour dosing interval. Doxazosin 1 to 16 mg once daily has been found to be comparable in efficacy to atenolol 50 to 100 mg and prazosin 1 to 20 mg daily. Characteristic of alpha 1-adrenoceptor antagonists, doxazosin also has favourable effects on the plasma lipid profile in that it decreases total cholesterol and triglycerides, and increases high density lipoprotein (HDL) cholesterol as well as the HDL/total cholesterol ratio. Although further long term trials are needed to clarify the role of doxazosin in multidrug regimens in more severe hypertension, it appears to be a suitable drug for consideration as first-line therapy in mild to moderate essential hypertension.
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PMID:Doxazosin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in mild or moderate hypertension. 289 95

Although the pathology of essential hypertension is still unclear, studies have shown that doxazosin, a selective alpha 1-inhibitor, is able to effectively control mild-to-moderate hypertension. The aim of these two, noncomparative studies was to evaluate the efficacy and toleration of doxazosin when used as monotherapy and in combination with other antihypertensive agents. In study I, 154 patients with standing and sitting diastolic blood pressures (DBPs) ranging from 95 to 115 mm Hg were treated with once-daily doxazosin (1 to 8 mg) as monotherapy for 12 weeks. Both sitting and standing blood pressures were significantly reduced by doxazosin monotherapy. Target DBP of less than or equal to 90 mm Hg was achieved in 86% of patients after 12 weeks of therapy with doxazosin, and there was no change in heart rate. Cholesterol and triglyceride levels were significantly decreased by doxazosin, but there was no change in glucose levels. Minor side effects were seen in 17.5% of patients, and 2.6% discontinued therapy. In study II, 65 patients with DBPs ranging from 95 to 115 mm Hg on existing antihypertensive therapies were concomitantly treated with doxazosin (1 to 8 mg) once daily for 12 weeks. Target DBPs of less than or equal to 90 mm Hg was achieved in 71% of patients after 12 weeks of therapy with doxazosin. There was no change in heart rate throughout the treatment period, and plasma cholesterol, triglyceride, and glucose levels remained essentially unchanged. Three patients, each receiving a beta-blocker, a diuretic, and doxazosin, were withdrawn because of side effects. Minor side effects, which were considered drug related were seen in 21% of patients. Doxazosin is a drug with good antihypertensive efficacy and is well tolerated as monotherapy and in combination with beta-blockers, thiazide diuretics, angiotensin converting enzyme inhibitors, and various combinations of these drugs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Control of coronary heart disease risk factors with doxazosin as monotherapy and in combination therapy. 290 47

A 12-week double-blind study was performed to compare the safety and efficacy of doxazosin, prazosin and placebo in 172 patients with essential hypertension. According to response, patients received doxazosin 1-16 mg once daily, prazosin 0.5-10 mg twice daily, or placebo. Mean final daily doses were doxazosin 11.3 mg and prazosin 13.8 mg. Doxazosin once daily and prazosin twice daily both produced statistically significant reductions in both standing and supine blood pressures when compared with placebo. No significant differences between treatments were recorded for standing and supine heart rates. Doxazosin, prazosin and placebo all had a similar effect on plasma lipid profiles, i.e. an increase in HDL/total cholesterol of approximately 10%. The differences between treatments were not statistically significant. The HDL/total cholesterol ratio significantly increased from baseline to the end of treatment for all three groups, the decrease in triglycerides being statistically significant only in the doxazosin-treated group.
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PMID:Multicentre 12-week double-blind comparison of doxazosin, prazosin and placebo in patients with mild to moderate essential hypertension. 293 70

Doxazosin is a new quinazoline derivative that, like prazosin, has selectivity for alpha 1-receptors. A three-way crossover, randomized, open study in 18 patients with essential hypertension was conducted to investigate the clinical pharmacokinetics of 2, 4, and 8 mg doxazosin at steady state. The pharmacokinetics of the initial 2 mg dose was also studied. Doxazosin showed linear pharmacokinetics. Increases in doses from 2 to 8 mg (steady state) produced proportional increases in doxazosin serum levels (maximum plasma drug concentration [Cmax] minimum plasma drug concentration [C min], and O-24-hour area under the curve [AUC(p-24)], whereas half-life (t1/2) (19.4, 18.7, and 19.7 hours, respectively), volume of distribution (3.4, 3.4, and 3.6 L/kg, respectively), clearance from serum (2.2, 2.2, and 2.1 ml/min/kg, respectively), and degree of protein binding (1.2%, 1.0%, and 1.0% unbound, respectively) were dose independent. Similar t1/2 and time to reach peak concentration (tmax) were obtained with 2 mg initial dose and 2 mg steady state. alpha 1-Acid glycoprotein levels were unchanged during doxazosin treatment. Doxazosin lowered supine and standing systolic and diastolic blood pressure. The blood pressure reduction was associated with an increase in heart rate. Peak hypotensive and tachycardic effects occurred 5.7 +/- 0.1 hours after administration, whereas Cmax was achieved at 2.4 +/- 0.7 hours (tmax). Greater decreases in systolic blood pressure and increases in heart rate were seen in standing than in supine position. The reduction in standing systolic and diastolic blood pressure with 8 mg was greater than with 2 mg (P less than 0.05); however, the increases in heart rate were not different. Dizziness, headaches, and dry mouth were the most frequent side effects. This study indicates that doxazosin shows linear pharmacokinetics between 2 and 8 mg and that because of its long t1/2, once-a-day administration should be adequate for the treatment of hypertension.
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PMID:Clinical pharmacology of doxazosin in patients with essential hypertension. 295 Oct 51

The acute effects of doxazosin, a new selective alpha-1 adrenergic blocking agent, on blood pressure, heart rate, and on some circulating vasoactive hormones, such as plasma renin activity, catecholamines, serotonin and endothelin-1 in ten healthy normotensive volunteers and eight moderate-severe essential hypertensives were studied. Two milligrams doxazosin was administered orally in randomised fashion as compared to placebo and the acute effects were evaluated one half to four hours later. Doxazosin did not reduce blood pressure and did not increase heart rate in normotensive subjects as compared to placebo. A significant decrease in blood pressure was found in hypertensives after doxazosin (p < 0.01), without change in heart rate. Simultaneously, doxazosin did not modify plasma renin activity, catecholamines, serotonin and endothelin-1 concentrations both in normotensive and hypertensive subjects when compared with placebo administration. Thus, it appears that doxazosin does not influence local and systemic vasopressor hormones involving in the regulation of blood pressure. In conclusion, the lack of effects on plasma vasoactive factors confirms the selective alpha-1 postsynaptic antagonism of doxazosin and an effective antihypertensive action in the treatment of essential hypertension.
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PMID:Acute effects of alpha-1 adrenoceptor antagonist, doxazosin on circulating vasoactive hormones. 748 Sep 65

Because none of the major studies used to document adverse or beneficial metabolic effects of antihypertensive drugs were made of non-Western patients with a non-Western diet, we compared doxazosin and hydrochlorothiazide in Korean patients receiving a Korean diet to determine if one regimen is superior to the other in terms of efficacy, adverse metabolic effects, or both. The randomized, double-blind, parallel study of Korean hypertensive patients compared the effects of oral doxazosin (mean +/- SD dose, 10.3 +/- 6.3 mg/day) and oral hydrochlorothiazide (44.0 + 11.0 mg/day) on blood pressure (BP) and lipid metabolism. The results of 48 patients treated for 20 weeks are reported here. Systolic (p < 0.001) and diastolic (p < 0.001) BP (SBP, DBP) were significantly lower in both groups at the end of the treatment period. Doxazosin significantly increased high-density-lipoprotein (HDL) cholesterol from a baseline of 1.10 +/- 0.31 to 1.27 +/- 0.30 mM (p < 0.05) and HDL/total cholesterol from 0.25 +/- 0.1 to 0.28 +/- 0.1 mM (p < 0.01). Hydrochlorothiazide significantly increased triglyceride from a baseline of 1.63 +/- 0.71 to 2.02 +/- 0.87 mM (p < 0.05). In contrast to Western studies, hydrochlorothiazide demonstrated no adverse effect on total, low-density-lipoprotein (LDL), or HDL cholesterol, or on HDL/total cholesterol. Indeed, HDL cholesterol was increased by 0.16 mM (p < 0.01). As in Western patients, doxazosin is effective for treatment of essential hypertension in Koreans and has no adverse effects but some beneficial effects on lipids.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of doxazosin and hydrochlorothiazide on lipid levels in Korean patients with essential hypertension. 750 34

Currently available data and clinical observations which suggest that there is a pathogenetic relationship between hypertension, diabetes mellitus, and atherosclerosis have provided a concept of the X syndrome, by which hypertensive patients, mainly males, have impaired insulin tolerance along with hyperinsulinemia and concurrent atherogenic disorders of lipid metabolism. The paper discussed the specific pathogenetic mechanisms, clinical manifestations, and prospects for drug correction of the metabolic syndrome. The treatment of arterial hypertension with the calcium antagonist Lomir has indicated there are no negative changes as a control of non-insulin-dependent diabetes mellitus in the presence of effective correction of arterial hypertension and atherogenic dyslipidemias. With the monotherapy of essential hypertension concurrent with hypercholesterolemia with the alpha 1-adrenoblocker Doxazosin, in addition to the agent's high antihypertensive effects, the authors noted its favourable action on lipid spectral parameters and platelet functional activity. There is abundant evidence for the use of specific hypolipidemic agents in patients with essential hypertensive refractory to current antihypertensive drugs. The data obtained with the use of Lescol (fluvastatin) in patients with hypertensive disease and hypercholesterolemia suggest that by substantially reducing the levels of total cholesterol, triglycerides, low density lipoprotein cholesterol and its transport protein apo B does not deteriorate the quality of correction of arterial hypertension in this group of patients.
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PMID:[Hypertension, diabetes mellitus, atherosclerosis: clinical manifestations of metabolic syndrome X. Prospects of pharmacological treatment]. 762 78

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

The central role of insulin resistance in patients with essential hypertension was the impetus for the present study, in which carbohydrate and lipid metabolism were examined before and after three months treatment with doxazosin (n = 14) and atenolol (n = 15). After completion of a randomised parallel group trial, the study was extended in a subgroup of the patients who continued treatment with doxazosin for a further nine months (n = 18). Insulin sensitivity was measured with the euglycemic hyperinsulinaemic clamp. Blood glucose and plasma insulin were analysed in the fasting state and during an intravenous glucose tolerance test (IVGTT). Lipoprotein fractions were analysed in serum. After three months, SBP and DBP in the standing position decreased to the same extent after the two drugs whereas the decrease in supine SBP did not reach statistical significance in the doxazosin group. Doxazosin, in contrast to atenolol, decreased serum triglycerides (-17%, P < 0.04) by lowering the VLDL and LDL fractions. Serum cholesterol fell after doxazosin (-7%, P < 0.02) but not after atenolol. The effects of doxazosin on serum lipids remained the same during the long-term follow-up. At three months neither drug had significantly affected variables reflecting insulin sensitivity although atenolol tended to decrease the insulin sensitivity index (-17%, P = 0.08). After 12 months the doxazosin group showed a significant increase in the insulin sensitivity index and a significant decrease in both basal plasma insulin and in the late insulin response at IVGTT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of selective alfa 1 and beta 1-adrenoreceptor blockade on lipoprotein and carbohydrate metabolism in hypertensive subjects, with special emphasis on insulin sensitivity. 800 23


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