Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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

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

Doxazosin, a selective alpha 1-inhibitor, was assessed in 34 patients with mild and moderate hypertension. This study involved three phases: (1) a 2-week baseline period, (2) an 8-week period in which patients received 1 to 8 mg of doxazosin once daily, and (3) a 4-week maintenance period. After 12 weeks, 77% of the efficacy evaluable patients were considered therapy successes (sitting diastolic blood pressure either less than or equal to 90 mm Hg with greater than or equal to 5 mm Hg reduction or greater than or equal to 10 mm Hg reduction) at a mean daily dose of 4.3 mg. Sixty-one percent achieved blood pressure control (sitting diastolic blood pressure less than or equal to 90 mm Hg) at a mean dose of 3.7 mg once daily. By the final treatment visit, systolic/diastolic blood pressures of efficacy evaluable patients were reduced by 17/12 and 17/11 mm Hg from a mean baseline of 160/100 and 156/101 mm Hg in the sitting and standing positions, respectively (p less than 0.05). Of the 34 patients, nine (26%) reported 12 adverse experiences, of which only one was severe. No clinically significant laboratory changes were apparent, and no trends were observed with regard to organ systems or correlations with dose or duration of treatment. The investigator's global assessment of efficacy of once-daily doxazosin therapy was excellent or good for 85% of patients and fair for 15% of patients. The investigator's global assessment of toleration was excellent or good for 91% of patients and fair for 9% of patients. The overall lipid profile indicated a decrease in total cholesterol and triglycerides.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Doxazosin in the treatment of mild and moderate essential hypertension in general medical practice. 290 46

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

Although surgical removal is the therapy of choice in patients with pheochromocytoma, medical management is necessary in the preoperative preparation of these patients and in inoperable cases. An alpha-adrenoceptor-blocking agent is routinely used as initial therapy to control hypertension, with a beta-blocker used as a second-step agent to control tachycardia when indicated. Doxazosin, a selective alpha 1-inhibitor used as an antihypertensive agent for the reduction of coronary heart disease risk in hypertensive patients, appears to be a good agent to control blood pressure with minimal changes in heart rate. The aim of this study was to assess the antihypertensive efficacy and safety of doxazosin when used alone or in conjunction with a beta-blocker in 24 patients with pheochromocytoma. Overall excellent or good antihypertensive efficacy was assessed by physicians in 19 of 24 patients (79.2%) enrolled in the study. Doxazosin monotherapy was effective in eight of 12 patients (66.7%), and combined therapy with a beta-blocker was effective in 11 of 12 patients (91.7%). The mean pulse rate remained constant throughout therapy. Adverse reactions were minor and transient and occurred in only three patients. Urinary and plasma catecholamine levels tended to decrease or remained unchanged during doxazosin therapy. There were no clinically hazardous abnormalities or problems in hematologic and biochemical laboratory data. Overall, doxazosin was considered very useful or useful in 83.3% of patients. In conclusion, doxazosin appears to be an excellent agent for the management of hypertension associated with pheochromocytoma.
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PMID:Doxazosin: a newly developed, selective alpha 1-inhibitor in the management of patients with pheochromocytoma. 290 51

The efficacy and toleration of doxazosin and atenolol were compared over a 52-week period in a double-blind, multicenter study of 228 patients with mild-to-moderate hypertension. Over the treatment period, both drugs significantly reduced blood pressure, and there were no clinically or statistically significant differences between treatment groups for reductions in standing systolic and diastolic blood pressures or in sitting diastolic blood pressure. However, atenolol treatment caused significantly greater reductions in sitting systolic blood pressure and heart rate. Neither drug significantly affected total serum cholesterol concentrations. Doxazosin treatment lowered serum triglycerides, whereas atenolol treatment produced an increase in serum triglycerides (p less than 0.001, week 30; p less than 0.01, week 50, between treatment groups). Increases in high-density lipoprotein cholesterol and high-density lipoprotein to total cholesterol ratio were obtained with doxazosin treatment, whereas atenolol treatment decreased these lipid fractions (p less than 0.0001, weeks 30 and 50, between treatment groups). Using the Framingham equation, it was calculated that at week 50 the risk of developing coronary heart disease was reduced by 22% for the group taking doxazosin (p less than 0.001 vs baseline) and by 4% (not significant) for patients taking atenolol (p = 0.01, between treatment groups). It is concluded that doxazosin is a well-tolerated and effective antihypertensive drug with a favorable effect on blood lipids. Doxazosin provides an attractive, new alternative first-line drug for the treatment of mild-to-moderate hypertension.
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PMID:Comparison of the effects of doxazosin and atenolol on blood pressure and blood lipids: a one-year, double-blind study in 228 hypertensive patients. 290 52

Doxazosin is a selective alpha 1-inhibitor for the reduction of calculated coronary heart disease (CHD) risk in hypertensive patients. Atenolol, although a widely used beta-blocker, appears to adversely affect blood lipids by increasing triglycerides and decreasing high-density lipoprotein (HDL) cholesterol. The aim of our study was to compare doxazosin and atenolol for their therapeutic efficacy in reducing CHD risk (decrease in blood pressure and effect on lipid distribution) and toleration. Patients with mild-to-moderate hypertension were randomized into two groups of 20 patients to receive once-daily atenolol (100 mg) or doxazosin (2 to 8 mg) for 8 weeks. Doxazosin was as effective as atenolol in reducing supine and standing blood pressure. Unlike atenolol, doxazosin did not produce a marked bradycardia. Doxazosin therapy produced favorable modifications in plasma lipid profiles by decreasing triglycerides and total cholesterol and by increasing HDL cholesterol and HDL/total cholesterol ratio. A reverse in this lipid profile was seen with atenolol. Therefore doxazosin may reduce calculated CHD risk more effectively than atenolol, based on the Framingham equation.
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PMID:Doxazosin versus atenolol: a randomized comparison of calculated coronary heart disease risk reduction. 290 53

Doxazosin, a quinazoline derivative, is a selective alpha 1-inhibitor that reduces calculated coronary heart disease risk by lowering blood pressure while favorably affecting blood lipid levels. The aim of this study was to compare the efficacy and toleration of doxazosin with atenolol, one of the most frequently used cardioselective beta-blockers in Italy. Forty patients with mild-to-moderate hypertension were treated with either atenolol (100 mg) or doxazosin (mean dose, 3.3 mg) once daily for 8 weeks. Both drugs significantly reduced supine and standing systolic and diastolic blood pressures. Atenolol induced marked bradycardia, whereas doxazosin had very little effect on heart rate. Doxazosin produced a favorable effect on blood lipid levels by decreasing triglyceride and total cholesterol levels and increasing high-density lipoprotein cholesterol and high-density lipoprotein total cholesterol ratio. Atenolol had exactly the opposite effect on blood lipid levels. Both drugs had equivalent toleration profiles. It was concluded that doxazosin was as effective as atenolol in reducing elevated supine and standing blood pressures. In addition, doxazosin had a beneficial effect on lipid profiles and minimal effect on heart rate. Therefore doxazosin may reduce calculated coronary heart disease risk in hypertensive patients.
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PMID:A comparative study of doxazosin versus atenolol in mild-to-moderate hypertension. 290 54

Antihypertensive treatment is known to reduce mortality in severe hypertension and cardiovascular morbidity in mild and moderately severe hypertension, for example, from stroke and left ventricular failure. However, treated hypertensive patients still have significantly higher mortality and morbidity than matched control subjects. In particular, risk of coronary heart disease is affected little by antihypertensive treatment. There may be several explanations for these less than optimal results. For example, blood pressure may not have been brought down to strictly normotensive levels or an antihypertensive agent, which adversely affects serum lipoproteins, may have been used, thereby offsetting the intended therapeutic effect. Doxazosin, a new selective alpha 1-inhibitor, offers both effective antihypertensive action and a favorable lipid effect. Both of these effects could have a positive impact on risk of coronary heart disease and therefore may prove to be more effective than previously used antihypertensive treatments.
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PMID:Implications of doxazosin therapy on risk of coronary heart disease. 290 59

Doxazosin is a long-acting selective alpha 1-adrenoceptor antagonist which has been shown to be effective and well tolerated in the treatment of hypertension given in once-daily doses as monotherapy for up to 1 year or as an adjunct to thiazide or beta-adrenoceptor blockers. Doxazosin has a pharmacokinetic profile in both young adult and elderly subjects which is compatible with once-daily administration. This has been confirmed by measurement of steady state pharmacokinetics in patients receiving long-term doxazosin therapy. In controlled double-blind studies involving approximately 550 patients on doxazosin 1-16 mg once daily, significant reductions in both standing and supine BP were maintained throughout the 24 h dosing interval. Effectiveness of doxazosin in terms of BP lowering and proportion of responders was similar to that achieved with hydrochlorothiazide 25-100 mg once daily, atenolol 50-100 mg once daily, nadolol 40-160 mg once daily, metoprolol 100-200 mg per day given twice daily, or prazosin 1-20 mg per day given twice daily. Doxazosin was as effective in elderly patients as in the younger age group and was as effective in blacks as in caucasians. Doxazosin was well tolerated. Side-effects were generally mild to moderate in severity. Overall incidence, including postural effects early in treatment, was similar to that seen with the comparative agents. In comparison with placebo, doxazosin favourably increased (P less than 0.05) the HDL/total cholesterol ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The antihypertensive effects of doxazosin: a clinical overview. 293 72

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


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