Effects of doxazosin on serum lipids: a review of the clinical data and molecular basis for altered lipid metabolism

Beneficial effects of non-quinazoline α1-adrenolytics on hypertension and altered metabolism in fructose-fed rats. A comparison with prazosin

BACKGROUND AND AIMS

Metabolic syndrome associated with insulin resistance and hypertension is often caused by excessive fructose consumption. Treatment of hypertension in patients with metabolic syndrome is a difficult task as many antihypertensive drugs have adverse effects on the metabolic profile. We investigated if MH-76 and MH-79, non-quinazoline α₁-adrenoceptor antagonists with an additional ability to stimulate NO/cGMP/K⁺ pathway, ameliorates metabolic syndrome in fructose-fed rats. As reference compound prazosin was used.

METHODS AND RESULTS

Male rats were divided into 5 groups (n = 8) and studied for 18 weeks: group control: standard diet and drinking water; group Fructose: high-fructose diet (20% fructose in drinking water); groups Fructose + MH-76, Fructose + MH-79, Fructose + prazosin: high-fructose diet with subsequent MH-76, MH-79 (5 mg/kg/day ip) or prazosin (0.2 mg/kg/day ip) treatment 12 weeks later. In addition to their antihypertensive effect, the studied compounds reversed endothelial dysfunction, decreased hyperglycemia and hypertriglyceridemia, as well as prevented abdominal adiposity. Moreover, MH-76 reduced insulin resistance and decreased TNF-α concentration and lipid peroxidation in adipose tissue. Prazosin treatment exerted an antihypertensive effect, reduced hyperglycemia but did not improve endothelial dysfunction, insulin resistance, and abdominal adiposity. The lower efficacy of prazosin may be the result of its short half-time and the lack of described pleiotropic effects.

CONCLUSIONS

α₁-adrenoceptor blockade, endothelial protection, TNF-α suppressing and antioxidant activity together with favorable pharmacokinetic parameters determines high efficacy of MH-76, leading to the effective improvement of hemodynamic and metabolic disturbances in metabolic syndrome. The use of non-quinazoline, multiple-targeted α₁-blockers may be an interesting option for treatment of hypertension with metabolic complications.

Orally applied doxazosin disturbed testosterone homeostasis and changed the transcriptional profile of steroidogenic machinery, cAMP/cGMP signalling and adrenergic receptors in Leydig cells of adult rats

Doxazosin (Doxa) is an α1-selective adrenergic receptor (ADR) antagonist widely used, alone or in combination, to treat high blood pressure, benign prostatic hyperplasia symptoms, and recently has been suggested as a potential drug for prostate cancer prevention/treatment. This study was designed to evaluate the effect of in vivo Doxa po-application, in clinically relevant dose, on: (i) steroidogenic machinery homeostasis; (ii) cAMP/cGMP signalling; (iii) transcription profile of ADR in Leydig cells of adult rats. The results showed that po-application of Doxa for once (1×Doxa), or for two (2×Doxa) or 10 (10×Doxa) consecutive days significantly disturbed steroidogenic machinery homeostasis in Leydig cells. Doxa po-application significantly decreased circulating luteinizing hormone and androgens levels. The level of androgens in testicular interstitial fluid and that extracted from testes obtained from 1×Doxa/2×Doxa rats decreased, although it remained unchanged in 10×Doxa rats. Similarly, the ex vivo basal androgen production followed in testes isolated from 1×Doxa/2×Doxa rats decreased, while remained unchanged in 10×Doxa rats. Differently, ex vivo testosterone production and steroidogenic capacity of Leydig cells isolated from 1×Doxa/2×Doxa rats was stimulated, while 10×Doxa had opposite effect. In the same cells, cAMP content/release showed similar stimulatory effect, but back to control level in Leydig cells of 10×Doxa. 1×Doxa/2×Doxa decreased transcripts for cAMP specific phosphodiesterases Pde7b/Pde8b, whereas 10×Doxa increased Pde4d. All types of treatment reduced the expression of genes encoding protein kinase A (PRKA) regulatory subunit (Prkar2b), whereas only 10×Doxa stimulated catalytic subunit (Prkaca). Doxa application more affected cGMP signalling: stimulated transcription of constitutive nitric oxide synthases (Nos1, Nos3) in time-dependent manner, whereas reduced inducible Nos2. 10×Doxa increased guanylyl cyclase 1 transcript and PRKG1 protein in Leydig cells. Orally applied Doxa significantly disturbed the transcriptional 'signature' of steroidogenic machinery, cAMP/cGMP signalling and ADRs and β-ADRs kinases in Leydig cells, thus giving new molecular insights into the role of cAMP/cGMP/adrenalin signalling in Leydig cells homeostasis.

Involvement of transcription factor activator protein-2alpha in doxazosin-induced HeLa cell apoptosis

AIM

To investigate the pro-apoptotic effects of alpha1-adrenergic inhibitor doxazosin in HeLa cells and the potential involvement of transcription factor activator protein-2alpha (AP-2alpha) in doxazosin-induced apoptosis.

METHODS

The HeLa cells were exposed to various concentrations of doxazosin for 16 h. Apoptosis was detected using a DNA fragmentation assay, Hoechst 33258 staining, and flow cytometric analysis. The expression of AP-2alpha and caspase-3 was detected by relative quantitative RT-PCR and Western blot assays, respectively. After the respective transfections of the HeLa cells with AP-2alpha overexpressing constructs and an antisense oligonucleotide against AP-2alpha, apoptosis was assessed by flow cytometric analysis, and the expression of AP-2alpha and caspase-3 was detected by relative quantitative RT-PCR and Western blot assays. The colorimetric assay was performed to detect the caspase-3 activity.

RESULTS

Treatment with various concentrations of doxazosin for 16 h increased the apoptotic rate and total cell death rate of the HeLa cells in a dose-dependent manner and upregulated the expression of AP-2alpha and caspase-3 in a dose-dependent manner. A dose-dependent increase was observed in the caspase-3 activity. Overexpressing AP-2alpha led to the increased rate of doxazosin-induced apoptosis and the total cell death, whereas doxazosin-induced apoptosis and the total cell death in HeLa cells decreased by antisense AP-2alpha. Furthermore, overexpressing AP-2alpha increased the expression and activity of caspase-3, whereas antisense AP-2alpha in part abolished the increased effects of doxazosin on caspase-3 expression and activity.

CONCLUSION

Doxazosin induces apoptosis in HeLa cells in a dose-dependent manner, and transcription factor AP-2alpha is functionally involved in doxazosin-induced HeLa cell apoptosis.

Effect of Doxazosin Gastrointestinal Therapeutic System on Patients with Uncontrolled Hypertension: The ASOCIA Study

OBJECTIVE

To evaluate extended-release doxazosin gastrointestinal therapeutic system (GITS) as add-on therapy in patients with treated, but uncontrolled hypertension.

METHODS

A 16-week, open, noncomparative, multicenter, prospective study of patients with hypertension (> or = 140/> or = 90 mm Hg). Doxazosin GITS 4 mg/d was added to entry medication and increased to 8 mg/d at Week 4 in cases of inadequate blood pressure (BP) control.

RESULTS

A total of 3631 patients (40% women) with mean age of 62.4 +/- 0.2 years were included. Proportion of patients reaching goal (< 140/< 90 mm Hg) after 4 weeks of add-on therapy with doxazosin GITS was 39% and increased to 61% at Week 16. Systolic and diastolic BP (mean +/- SEM) decreased, respectively, from 161.6 +/- 0.2 and 95.1 +/- 0.1 mm Hg at baseline to 142.2 +/- 0.2 and 84.1 +/- 0.1 mm Hg at Week 4 (P < 0.0001) and 136.8 +/- 0.2 and 80.6 +/- 0.2 mm Hg at Week 16 (P < 0.0001). Adverse events occurred in 108 patients (3.0%), with 57 (1.6%) related to the study treatment. In 17 patients (0.5%), serious adverse events were described, but only one was related to the study drug.

CONCLUSIONS

Doxazosin GITS as add-on therapy achieved target blood pressure and was well tolerated in patients with hypertension uncontrolled by previous regimens. Doxazosin GITS efficacy and tolerability was achieved in combination with all classes of antihypertensives tested.

Doxazosin for benign prostatic hyperplasia: An open-label, baseline-controlled study in Korean general practice

BACKGROUND

Few studies have reported the treatment of benign prostatic hyperplasia (BPH) in Asian patients. We assessed the safety and efficacy of doxazosin, a selective alpha1-adrenoceptor antagonist, in the treatment of Korean patients with symptomatic BPH.

METHODS

Two hundred and ninety-five men, aged 48 years or older with clinical BPH, were enrolled in a 12-week, open-label, baseline-controlled, dose-titration, multicenter study. A 2-week, single-blind, placebo run-in was followed by 10 weeks of doxazosin treatment, initially administered at 1 mg/day, with upward titrations (2, 4, or 8 mg/day) at 2-week intervals. The international prostate symptom score (IPSS) was used to assess efficacy after 4, 6, and 10 weeks of active treatment.

RESULTS

The intent-to-treat (ITT) population comprised 249 patients (mean age 63.6 years). Doxazosin significantly reduced the mean total IPSS by 48%; similarly, the obstructive and irritative subscores were reduced from baseline by 51% and 39%, respectively (P < 0.001 for all scores: Wilcoxon rank sum test). In a subset analysis of 170 normotensive and 78 hypertensive patients, significant reductions in mean systolic and diastolic blood pressures relative to baseline were observed only in the hypertensive subset (P < 0.01). Similar results in mean IPSS were observed in older (> or =65 years, n = 100) and younger (45-64 years, n = 140) patients, as well as between normotensive and hypertensive patients. Thirty-nine patients reported adverse events: The most frequent were dizziness, dyspepsia, asthenia, somnolence, and dry mouth.

CONCLUSIONS

The efficacy and safety of doxazosin treatment for BPH were confirmed in this Asian population. Significant improvements in total IPSS, as well as obstructive and irritative subscores, were observed.

Renoprotective Effect of Angiotensin-Converting Enzyme Inhibitor Combined with α1-Adrenergic Antagonist in Spontaneously Hypertensive Rats with Renal Ablation

To assess the renal benefits of combined angiotensin-converting enzyme inhibition and alpha(1)-adrenergic antagonism, we studied the antihypertensive and renoprotective effects of temocapril (TMP) alone and in combination with doxazosin (DOX) in spontaneously hypertensive rats (SHR)/Izumo rats with renal ablation. Five-Sixths-nephrectomized rats were assigned to receive TMP (10 mg/kg/day) (TMP group), TMP plus DOX (2 mg/kg/day) (TMP+DOX group), or vehicle (control group) orally for 12 weeks. Both systolic blood pressure (SBP) and urinary excretion of albumin (UalbV) in the control group progressively increased during the experimental period and were significantly higher than in sham-operated rats. Treatment with either TMP or TMP plus DOX had similar antihypertensive effects in this rat model. Twelve weeks after initiation of treatment, the SBP values in the control, TMP, and TMP+DOX groups were 265+/-8, 157+/-4, and 163+/-3 mmHg, respectively, in comparison with 233+/-4 mmHg in sham-operated rats (p<0.0001 control vs. sham, p<0.001 TMP vs. control, p<0.001 TMP+DOX vs. control). UalbV, serum creatinine (Scr), blood urea nitrogen (BUN), and heart weight/body weight (HW/BW) ratio were significantly lower in the TMP and TMP+DOX groups than in the control group (UalbV: p<0.05; Scr: p<0.01; [BUN, HW/BW ratio]: p<0.0001; and [UalbV, Scr, BUN, HW/BW ratio]: p<0.0001 vs. control, respectively). The index of glomerular sclerosis (IGS) and relative interstitial volume (RIV) were significantly lower in the TMP+DOX group than in the control group (IGS: p<0.05; RIV: p<0.01). Especially, UalbV, IGS, and RIV were significantly better in the TMP+DOX group than in the TMP group ([IGS, RIV]: p<0.05; UalbV: p<0.01). These results suggest that simultaneous administration of TMP and DOX provides greater renoprotective effects than administration of TMP alone.

Doxazosin, an alpha-1 antagonist, prevents further progression of the advanced atherosclerotic lesion in hypercholesterolemic hamsters

The aim of this study was to examine the effect of doxazosin (DOX) on the further progression and regression of the advanced atherosclerotic lesion in the hypercholesterolemic hamster. Thirty-six, male F(1)B Golden Syrian hamsters, 10 weeks of age, were divided into 3 groups of 12 and fed a nonpurified hypercholesterolemic diet (HCD) containing 10% coconut oil and 0.1% cholesterol (wt/wt) for 9 months (HCD 9). One group of hamsters was euthanized at 9 months and their aortas were collected, fixed, and stored until analysis. The remaining hamsters were either maintained on the HCD for an additional 6 months (HCD 15) or fed the HCD plus 20 mg/kg/d DOX for the 6 months. At the end of the study (15 months), the DOX-treated hamsters had significantly lower plasma total cholesterol (TC) (-68%), low-density lipoprotein-cholesterol (LDL-C) (-73%), and triglycerides (TG) (-74%) compared with the HCD 15. The lumenal narrowing and intimal thickening atherosclerotic lesions were significantly less in the DOX-treated hamsters compared with the HCD 15 (-66% and -70%, respectively). These data suggest that DOX treatment prevents further progression of the advanced atherosclerotic lesion possibly by lowering plasma TC, LDL-C, and TG in hypercholesterolemic hamsters.

Low-dose doxazosin improved aortic stiffness and endothelial dysfunction as measured by noninvasive evaluation

Evaluation of atherosclerosis is important in the treatment of hypertension. To evaluate the preventive effects of a small amount of alpha-blockade, arterial and endothelial dysfunction were measured by noninvasive tests, i.e., pulse wave velocity, acceleration plethysmography and strain-gauge plethysmography, in patients with essential hypertension. Fifteen patients (65+/-3 years old) with essential hypertension (WHO stage I or II) were analyzed in this study. We performed noninvasive evaluations to measure aortic stiffness and endothelial dysfunction, in addition to measuring blood pressure, cholesterol profile, and levels of cells adhesion molecules and nitric oxide before and 6 and 12 months after the start of doxazosin treatment (1.0 mg/day). Blood pressure and heart rate did not significantly change during treatment. The pulse wave velocity index was significantly reduced both at 6 (7.72+/-0.23 m/s; p<0.05) and 12 (7.34+/-0.26 m/s; p<0.05) months after the start of treatment compared to the pretreatment level that at baseline. There was also a significant improvement in b/a after 12 months (-0.46+/-0.04; p<0.05) and in d/a after 6 months (-0.38+/-0.03; p<0.05) and 12 months (-0.39+/-0.03; p=0.05) compared to the pretreatment values. Moreover, reactive hyperemia evaluated by strain-gauge plethysmography after 6 months (1.34+/-0.11; p<0.05) and 12 months (1.49+/-0.16; p<0.05) was significantly improved compared to that before treatment, and NOx was significantly increased after 12 months (89.7+/-15.7 micromol/l; p<0.005). These data suggest that a low dose of doxazosin may play an important role in improving arterial stiffness and endothelial dysfunction without changing cardiac hemodynamics.

Platelet alpha2-adrenoceptor alterations in patients with essential hypertension are normalized after treatment with doxazosin but not propranolol

OBJECTIVE

Marked alterations have been demonstrated to occur in the platelet alpha2-adrenoceptors of patients with essential hypertension. The purpose of this study was to determine whether antihypertensive treatment with alpha-adrenergic blocker doxazosin or beta-adrenergic blocker propranolol can affect the affinity and the density of platelet alpha2-adrenoceptors in such patients.

SUBJECTS AND METHODS

In two groups of 22 previously untreated, essential hypertensive patients, the mean affinity (Kd) and density (B(max)) of platelet alpha2-adrenoceptors were studied by [3H]-UK 14304 binding assays; the first assays were performed before any medication was begun, the second were performed after treatment for up to 13 weeks with doxazosin or propranolol. A third group of 22 healthy normotensive volunteers matched by age, sex and body mass index was used as control.

RESULTS

Blood pressure did not differ significantly in the two hypertensive groups, and treatment with the two drugs resulted in closely similar, normal blood pressure levels. Kd and B(max) values were significantly higher in the two hypertensive groups than in controls. After treatment with propranolol the binding parameters did not change significantly, whereas after treatment with doxazosin Kd and B(max) returned to normotensive values.

CONCLUSIONS

In previously untreated, essential hypertensive patients platelet alpha2-adrenoceptors have a lower affinity but a higher density than in normotensive subjects. Despite similar effects on blood pressure, the treatment with the alpha-adrenergic blocker doxazosin is followed by restoration of normal findings in the binding assays of platelet alpha2-adrenoceptors whereas the treatment with the beta-adrenergic blocker propranolol does not alter the Kd and B(max) values.

Modulation of the differentiation status of cultured prostatic smooth muscle cells by an alpha1-adrenergic receptor antagonist

BACKGROUND

Prostatic stromal cells are believed to be a key factor in the pathogenesis of benign prostatic hyperplasia (BPH). The effect of phenylephrine, an alpha1-adrenergic receptor agonist, and doxazosin, an alpha1-adrenergic receptor-specific antagonist, on the expression of smooth muscle myosin-heavy-chain isotypes SM-1 and SM-2 was tested in an in vitro model of prostatic smooth muscle cells (SMC).

METHODS

Primary prostatic stromal cells, grown in SMC-specific medium, were treated with 10 microM of phenylephrine or 1 microM of doxazosin or a combination of both. SM-2 to SM-1 mRNA ratios and expression of alpha1-adrenergic receptor subtypes were determined by means of reverse transcriptase polymerase chain reaction (RT-PCR) techniques. Cell growth was measured by a cell viability assay.

RESULTS

SM-1 mRNA and only very low levels of SM-2 mRNA were detected in prostatic SMC cultures grown for 4 days in a serum-free base medium. After 6 days of treatment, SM-2 expression increased, highest in the doxazosin-treated cultures. In comparison to unstimulated cells, a statistically significant 10-fold increase of the SM-2:SM-1 ratio was measured in doxazosin-treated cultures. Analysis of alpha1-adrenergic receptor subtype expression revealed the presence of mRNAs of subtypes 1d and 1b mRNAs. Subtype 1a was not expressed. Phenylephrine and doxazosin showed no significant effect on cell proliferation and on alpha1d-adrenergic receptor expression.

CONCLUSIONS

SMC can differentiate from a proliferative to a contractile phenotype, which is accompanied by increased expression of isotope 2 of smooth muscle myosin heavy chain. Our results suggest that doxazosin seems to have a long-term effect on the differentiation of prostatic stromal cells, indicating that alpha1-adrenergic receptor antagonists do not act solely on SMC contractility.

Prostatic alpha 1-adrenoceptors and uroselectivity

BACKGROUND

alpha 1-adrenoceptor antagonists (blockers) are now commonly used in the treatment of the symptoms of lower urinary tract obstruction. Originally phenoxybenzamine, a non-selective antagonist at both alpha 1- and alpha 2-adrenoceptors, was used by Marco Caine. In an attempt to minimize side effects, selective alpha 1-antagonists, e.g. prazosin, were subsequently developed. More recently, agents such as alfuzosin, doxazosin, terazosin, and tamsulosin have been introduced and claims of "uroselectivity" and "prostate" selectivity have emerged.

METHODS

This review attempts to put these claims into perspective and represents a comprehensive analysis of all pre-clinical and clinical data including several papers from the Japanese literature. An attempt is made to define what is meant by selectivity at various levels including the test tube, in the laboratory animal and, most importantly, in the clinical context of the whole patient.

CONCLUSIONS

The conclusions are interpreted within the context of the subdivision of the alpha 1-adrenoceptor into alpha 1A, alpha 1B, and alpha 1D subtypes.

Nerve function in galactosaemic rats: effects of evening primrose oil and doxazosin

Rats were fed for 6 weeks with a 40% galactose diet to chronically stimulate the polyol pathway. Sciatic motor and saphenous sensory nerve conduction velocity deficits of 22% and 14% respectively developed. Treatment with evening primrose oil or doxazosin from galactosaemia induction partially (approximately 60%) prevented the development of reduced motor and sensory conduction, the former treatment being more successful than the latter. Sciatic nerve resistance to hypoxic conduction failure was 49% increased by galactosaemia. This abnormality was 27% and 43% prevented by doxazosin and evening primrose oil respectively. Galactosaemic sciatic nerves had a 10% increase in water content and endoneurial capillary density was 24% reduced. While neither treatment affected water content, both caused angiogenesis, elevating capillary density by approximately 16%. The data support the hypothesis that, as in experimental diabetes mellitus, the main effect of polyol pathway activation on peripheral nerve function occurs indirectly via a neurovascular action.

Doxazosin--an alpha-1 receptor blocking agent in the long-term management of benign prostatic hyperplasia (BPH) (Part Two)

This part of our study presents results of laboratory evaluations in patients with BPH during treatment with prazosin and doxazosin. After 72 weeks serum PSA and PAP fell by 40.2% and 82%, respectively. Blood urea nitrogen concentration decreased by 28.5% and serum creatinine by 20.8%. The results confirm long-term favourable effects of the therapy of patients with BPH.

Doxazosin. An update of its clinical pharmacology and therapeutic applications in hypertension and benign prostatic hyperplasia

Doxazosin is a long-acting alpha 1-adrenoceptor antagonist structurally related to prazosin and terazosin. Its antihypertensive effect is produced by a reduction in the smooth muscle tone of peripheral vascular beds resulting in a decrease in total peripheral resistance without significant effect on cardiac output or heart rate. In benign prostatic hyperplasia, doxazosin's effect of relieving bladder outflow obstruction is produced through a reduction in prostatic tone mediated via alpha 1-adrenoceptor blockade. In most comparative trials doxazosin has proven to be equally effective as the comparator drug in the treatment of mild to moderate hypertension. It has been used in a variety of patient populations including the elderly, Blacks, smokers, and patients with concomitant disease states such as renal dysfunction, hypercholesterolaemia, non-insulin dependent diabetes mellitus (NIDDM) and respiratory disease. Doxazosin has also been used successfully in combination with beta-adrenoceptor antagonists, diuretics, calcium channel antagonists, and angiotensin-converting enzyme inhibitors in patients with hypertension that is uncontrolled with monotherapy. Doxazosin has a beneficial effect on some of the risk factors associated with coronary heart disease including elevated serum lipid levels, impaired glucose metabolism, insulin resistance and left ventricular hypertrophy. Modest decreases in total cholesterol, low density lipoprotein cholesterol and triglycerides are seen with doxazosin therapy while small increases in high density lipoprotein cholesterol and the high density lipoprotein cholesterol/total cholesterol ratio are consistently reported. Some studies have reported an improvement in glucose tolerance although this effect has been more consistently seen in nondiabetic patients than in patients with NIDDM. Additionally, doxazosin produces a similar reduction in left ventricular hypertrophy to other antihypertensive agents. Modelling-based calculations suggest that doxazosin significantly reduces the risk of developing coronary heart disease in patients with mild to moderate hypertension, although this remains to be confirmed in long term prospective studies. Doxazosin appears to be a promising agent in the treatment of urinary symptoms associated with benign prostatic hyperplasia. Similar to other alpha 1-adrenoceptor antagonists, doxazosin treatment produces increases in peak and mean urinary flow rates and improves other objective and symptomatic measures.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of doxazosin, an alpha 1-adrenergic inhibitor, on plasma lipid and lipoprotein levels, low density lipoprotein metabolism and cholesterol absorption in cynomolgus monkeys

The mechanism(s) by which doxazosin, an alpha 1 inhibitor, regulates plasma low density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apo B) levels were investigated in 'normocholesterolemic' (average total cholesterol (TC) of 218 mg/dl) and 'hypercholesterolemic' (average TC of 350 mg/dl) cynomolgus monkeys. Twelve weeks of doxazosin treatment (1 mg/kg per day) significantly reduced plasma TC and LDL-C levels in both groups while high density lipoprotein cholesterol and apolipoprotein A-I concentrations rose. Despite these changes in plasma lipids, LDL and HDL lipid composition was not affected by doxazosin. The reduction in LDL-C and apo B in the doxazosin-treated 'hypercholesterolemic' group was associated with a significant increase in both receptor-dependent and -independent LDL apo B fractional catabolic rates. Similar associations were noted in the 'normocholesterolemic' group. LDL apo B production or transport rate was not affected by doxazosin. Cholesterol absorption was also significantly reduced by doxazosin which may also contribute to lowering plasma LDL-C levels. These studies suggest that doxazosin treatment can produce beneficial changes in the plasma lipid profile over a wide rage of plasma cholesterol levels by up-regulating LDL fractional clearance.

A comparison of the effects of the selective peripheral alpha 1-blocker terazosin with the selective beta 1-blocker atenolol on blood pressure, exercise performance and the lipid profile in mild-to-moderate essential hypertension

The effects of six weeks of treatment with the selective peripheral alpha 1-adrenoceptor blocker terazosin, or the selective beta 1-adrenoceptor blocker atenolol on blood pressure, exercise performance and blood lipid profile were compared in a single-blind, randomized, crossover study of 17 patients with mild-to-moderate essential hypertension. Although both drugs significantly reduced blood pressure at rest, atenolol caused a larger fall in supine blood pressure (11/11 and 7.5/7.0 mmHg, atenolol and terazosin, respectively; p < 0.001). Both treatments controlled the pressor response to exercise, although a greater reduction in diastolic blood pressure was observed at the end of exercise on terazosin (74.0 +/- 5.7 and 91.6 +/- 4.0 mmHg, terazosin and atenolol, respectively; p < 0.01). Alpha 1-blocker therapy was not associated with any measurable improvement or deterioration in cardiopulmonary performance and exercise duration. Unlike atenolol, terazosin therapy had the potentially beneficial effect of reducing serum total cholesterol levels and increasing the high-density lipoprotein-cholesterol/low-density lipoprotein-cholesterol ratio.

Effective treatment of hypertension in patients with diabetes mellitus

Atherosclerosis, presenting as macrovascular complications of diabetes mellitus, produces approximately 80% of all diabetic mortality, whether the patient has Type I insulin-dependent diabetes (IDDM) or Type II non-insulin dependent diabetes mellitus (NIDDM). Specifically, 75% of this atherosclerotic macrovascular mortality flows as the outcome of coronary atherosclerosis, which is increased approximately two-fold in men and four-fold in women with diabetes as compared with otherwise matched populations with entirely normal carbohydrate tolerance. The remaining 25% of this atherosclerotic mortality in patients with diabetes mellitus is the result either of accelerated cerebrovascular or of peripheral vascular complications of diabetes, both of which are increased four-fold and five-fold, respectively, in patients with diabetes mellitus, regardless of type. Furthermore, atherosclerosis is the principal cause of hospitalizations for patients with diabetes mellitus. Admissions for this complication account for approximately 77% of total hospitalizations for diabetes owing to complications. Aside from mortality data alone, atherosclerosis is obviously a leading cause of diabetic disability, since it produces patients who are chronic cardiovascular, peripheral or cerebrovascular cripples, perhaps for many years before their ultimate demise. Small blood vessel or microvascular complications of diabetes mellitus, while formerly thought to be the end-stage in the unfolding of the diabetic process, do not appear to have the potential for mortality as do the atherosclerotic large blood vessel complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Doxazosin effects on insulin and glucose in hypertensive patients. The Finnish Multicenter Study Group

This study investigates the effects of prolonged doxazosin treatment on serum lipids, glucose, serum insulin, and blood pressure in hypertensive patients. Following 26 weeks of treatment with doxazosin, supine and standing blood pressures were significantly decreased at a final mean daily dose of 6.4 mg. Blood glucose levels were significantly lower at 26 weeks than after the initial placebo period (p less than 0.05) or after 4 weeks' treatment with doxazosin (p less than 0.001). There was a significant (p less than 0.05) decrease in serum insulin levels following 4 weeks of treatment, and a highly significant (p less than 0.001) decrease after 26 weeks. In addition, doxazosin produced a significant reduction in total cholesterol (p less than 0.05) and low-density lipoprotein (LDL) cholesterol (p less than 0.01) after 26 weeks, although the levels of high-density lipoprotein (HDL) cholesterol, very-low-density lipoprotein (VLDL) cholesterol, and triglycerides showed no significant change. There was a tendency for the ratio of HDL: total cholesterol to increase. The combined changes in blood pressure, blood glucose levels, serum insulin, and serum lipids favorably affect the probability of developing coronary heart disease (CHD).

Management of multiple risk factors for coronary heart disease in patients with hypertension

Hypertension intervention trials, which have involved mainly the use of diuretics and beta-blockers, have demonstrated a disappointing benefit in terms of reduction of coronary heart disease (CHD). Rather than suggesting that elevated blood pressure and CHD are not causally related, these data suggest that the antihypertensive agents used were not optimal for the management of hypertension and a review of the currently recommended therapies is needed. Major risk factors for CHD, which include increased blood pressure, elevated serum cholesterol levels, and smoking, are highly prevalent in the general population and appear to cluster in patients with hypertension. Therefore the treatment of hypertension demands a multifactorial approach, one that takes into consideration all the risk factors for CHD. Diuretics and beta-blockers adversely affect the serum lipid profile, and this could negate some of the CHD benefit afforded by blood pressure reduction.

Doxazosin: a study in a cohort of patients with hypertension in general practice--an interim report

The objective of this study was to assess the safety and efficacy of doxazosin in a substantial cohort of hypertensive patients drawn from general practice. A total of 4027 patients entered the study, 1472 of whom (36.6%) were untreated hypertensive patients. Patients were not advised to change diet, smoking habit, or life-style during the study. Twenty-one percent were cigarette smokers, and concurrent diabetes was present in 2.3%. Baseline blood cholesterol exceeded 200 mg/dl (5.2 mmol/L) in 90% and 250 mg/dl (6.5 mmol/L) in 56% of patients. The mean decrease in blood pressure produced by doxazosin was 22/15 mm Hg after 10 weeks of therapy; there was a mean decrease in heart rate of 1 beat/min. The mean maintenance dose for all patients was 3.1 mg/day. Side effects considered related or possibly related to treatment were reported in 705 patients. Treatment was discontinued in 233 patients (5.8%) because of adverse events related or possibly related to treatment with doxazosin. Doxazosin produced a significant (p less than 0.001) decrease in total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels and a significant increase in high-density lipoprotein cholesterol and the ratio of high-density lipoprotein:total cholesterol. The potential reduction in 10-year coronary heart disease risk (according to the Framingham equation) was calculated to be 20.4%.