Characteristics and lipid distribution of a large, high-risk, hypertensive population: the lipid-lowering component of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) consisted of 42,418 participants randomized to one of four antihypertensive treatment groups: chlorthalidone, amlodipine, lisinopril, or doxazosin. A subset of these participants with fasting low-density lipoprotein cholesterol levels 100-189 mg/dL were randomized into a lipid-lowering component: 5170 to receive pravastatin (40 mg daily) and 5185 to receive usual care. This report describes the characteristics and lipid distribution of these participants. There were no important differences between the randomized treatment groups. Women had higher total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol than men. There was a similar finding for black participants compared with whites, except blacks had lower triglycerides. Diabetics had lower high-density lipoprotein cholesterol and higher triglycerides than nondiabetics, and patients with body mass index <25 kg/m(2) had higher high-density lipoprotein cholesterol but lower low-density lipoprotein cholesterol and triglycerides than patients with higher body mass index. The success of the randomization of this large, diverse population and the differences in the lipid distributions among its subgroups will allow further understanding of optimal lipid-lowering treatment.

Fibrosis-related gene expression in the prostate is modulated by doxazosin treatment

AIMS

To gain new insights into the molecular mechanisms of action of doxazosin, we investigated the prostatic stroma ultrastructure and the expression of genes involved with fibrosis, such as collagen type I and III (COL1A1 and COL3A1, respectively) and TGF-beta 1, in the rat ventral prostate.

MAIN METHODS

Adult Wistar rats were treated with doxazosin (25mg/kg/day), and the ventral prostates were excised at 7 and 30days after treatment. Untreated rats were controls. Ventral prostates were subjected to ultrastructural, immunohistochemical, biochemical and molecular analyses.

KEY FINDINGS

Doxazosin-treated prostates showed thickened bundles of collagen fibrils, activated fibroblasts, enlarged neurotransmitter vesicles and increased tissue immunostaining for collagen type I and type III when compared to untreated prostates. After 7 and 30days of doxazosin treatment mRNA expression of COL1A1 and COL3A1 was significantly increased and reduced, respectively, compared to the control group. TGF-beta 1 mRNA and protein levels were increased after 7days of doxazosin treatment, whereas only mRNA levels remained increased after 30days of treatment.

SIGNIFICANCE

Our data suggest that relaxation of smooth muscle cells by alpha-blockers interferes with the mechanical dynamics of the prostatic stroma extracellular matrix components, generating a pro-fibrotic effect probably via the TGF-beta 1 signaling pathway. Long term treatment with doxazosin may also lead to a reduced turnover of extracellular matrix components. Our results add to a better understanding of the molecular mechanisms behind the effects of alpha-blockade on prostatic histoarchitecture and the response to treatment for benign prostatic hyperplasia.

Cytoplasmic free calcium mobilization in platelets, expression of P-selectin, phosphatidylserine, and microparticle formation, measured by whole blood flow cytometry, in hypertensive patients. Effect of doxazosin GITS

The effects of doxazosin on expression of CD62 (P-selectin) and phosphatidylserine on platelet membrane and platelet calcium flux were studied in 50 uncomplicated essential hypertensive patients (World Health Organization stages 1-2) and 80 normotensive control subjects, matched for age, sex, and cardiovascular risk factors. Hypertensive patients showed greater in vivo platelet activation at baseline than control patients (percentage of CD62-positive platelets, 4.1+/-2.2% versus 2.4+/-1.5%, p<0.001; percentage of phosphatidylserine-positive platelets, 0.8+/-0.5% versus 0.5+/-0.3%, p<0.001). Increased platelet activation was associated with significant changes in the mobilization of free intraplatelet calcium, evaluated by a whole blood flow cytometric kinetic method. With this method, an arbitrary Ca(2+) mobilization index was defined as the ratio of cytoplasmic free calcium before activation with thrombin to the slope of the calcium removal rate following the action of the agonist. This index was significantly higher in untreated hypertensive patients than in normotensive controls (0.12+/-0.06 versus 0.05+/-0.08, p<0.001). Treatment of hypertensive patients with doxazosin gastrointestinal therapeutic system (4 mg/day as a single dose) for 2 months normalized both platelet activation and Ca(2+) mobilization. Changes in the expression of CD62 and phosphatidylserine in the platelet membrane after treatment with doxazosin gastrointestinal therapeutic system may be related to normalization of the kinetics of cytoplasmic free Ca(2+). Normalization of platelet activation may represent an additional beneficial effect to the known antihypertensive action of doxazosin gastrointestinal therapeutic system.

Assessment of Frailty and Association With Progression of Benign Prostatic Hyperplasia Symptoms and Serious Adverse Events Among Men Using Drug Therapy

IMPORTANCE

Benign prostatic hyperplasia (BPH) in older men can cause lower urinary tract symptoms (LUTS), which are increasingly managed with medications. Frailty may contribute to both symptom progression and serious adverse events (SAEs), shifting the balance of benefits and harms of drug therapy.

OBJECTIVE

To assess the association between a deficit accumulation frailty index and clinical BPH progression or SAE.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Medical Therapy of Prostatic Symptoms trial, which compared placebo, doxazosin, finasteride, and combination therapy in men with moderate-to-severe LUTS, reduced urinary flow rate, and no prior BPH interventions, hypotension, or elevated prostate-specific antigen. Enrollment was from 1995 to 1998, and follow-up was through 2001. Data were assessed in February 2021.

EXPOSURES

A frailty index (score range, 0-1) using 68 potential deficits collected at baseline was used to categorized men as robust (score ≤0.1), prefrail (score 0.1 to <0.25), or frail (score ≥0.25).

MAIN OUTCOMES AND MEASURES

Primary outcomes were time to clinical BPH progression and time to SAE, as defined in the parent trial. Adjusted hazard ratios (AHRs) were estimated using Cox proportional hazards regressions adjusted for demographic variables, treatment group, measures of obstruction, and comorbidities.

RESULTS

Among 3047 men (mean [SD] age, 62.6 [7.3] years; range, 50-89 years) in this analysis, 745 (24%) were robust, 1824 (60%) were prefrail, and 478 (16%) were frail at baseline. Compared with robust men, frail men were older (age ≥75 years, 12 men [2%] vs 62 men [13%]), less likely to be White (646 men [87%] vs 344 men [72%]), less likely to be married (599 men [80%] vs 342 men [72%]), and less likely to have 16 years or more of education (471 men [63%] vs 150 men [31%]). During mean (SD) follow-up of 4.0 (1.5) years, the incidence rate of clinical BPH progression was 2.2 events per 100 person-years among robust men, 2.9 events per 100 person-years among prefrail men (AHR, 1.36; 95% CI, 1.02-1.83), and 4.0 events per 100 person-years among frail men (AHR, 1.82; 95% CI, 1.24-2.67; linear P = .005). Larger point estimates were seen among men who received doxazosin or combination therapy, although the test for interaction between frailty index and treatment group did not reach statistical significance (P for interaction = .06). Risk of SAE was higher among prefrail and frail men (prefrail vs robust AHR, 1.81; 95% CI, 1.48-2.23; frail vs robust AHR, 2.86; 95% CI, 2.21-3.69; linear P < .001); this association was similar across treatment groups (P for interaction = .76).

CONCLUSIONS AND RELEVANCE

These findings suggest that frailty is independently associated with greater risk of both clinical BPH progression and SAEs. Older frail men with BPH considering initiation of drug therapy should be counseled regarding their higher risk of progression despite combination therapy and their likelihood of experiencing SAEs regardless of treatment choice.

A double-blind placebo-controlled study evaluating the onset of action of doxazosin gastrointestinal therapeutic system in the treatment of benign prostatic hyperplasia

OBJECTIVE

To determine the onset of improvement in benign prostatic hyperplasia symptoms in patients after treatment with doxazosin gastrointestinal therapeutic system (DOX GITS) versus placebo.

METHODS

In this prospective, randomized, double-blind, placebo-controlled trial, baseline values, including International Prostate Symptom Score (IPSS) and maximum urine flow rate (Q(max)), were determined following a 2-week placebo run-in. Patients received DOX GITS 4 mg/d (n = 108) or placebo (n = 105) for 14 days. IPSS was measured on Days 3, 7, and 14; Q(max) on Days 1, 3, 7, and 14; and the patients' perception of improvement was measured on Days 1 and 2 in the evening at home and in the office on Day 14.

RESULTS

Significantly more patients treated with DOX GITS than placebo perceived improvement after Day 1 (60.6% vs. 41.9%) through Day 14 (84.3% vs. 64.1%). On Day 1, improvement in Q(max) with DOX GITS was not significantly different compared with placebo. On Day 3 of the trial (1) IPSS improvement was significantly greater with DOX GITS than with placebo; (2) proportion of patients with > or =30% improvement in IPSS was significantly greater with DOX GITS (49.5%) than placebo (28.4%) and remained so through Day 14; (3) improvement in Q(max) was significantly greater with DOX GITS (3.7 mL/s) than placebo (1.9 mL/s) and remained so through Day 14; (4) proportion of patients with > or =3 mL/s increase in Q(max) was statistically greater with DOX GITS (54.4%) versus placebo (30.8%) and remained so through Day 14.

CONCLUSIONS

DOX GITS significantly improved IPSS and Q(max) by Day 3 of treatment, and these changes were maintained through Day 14. More patients receiving DOX GITS than placebo perceived improvement in symptoms as early as Day 1.

Long-term follow-up study to evaluate the efficacy and safety of the doxazosin gastrointestinal therapeutic system in patients with benign prostatic hyperplasia with or without concomitant hypertension

OBJECTIVE

To assess the long-term efficacy and safety of extended-release doxazosin gastrointestinal therapeutic system (GITS) under routine clinical care conditions over 12 months in Korean men with benign prostatic hyperplasia (BPH) with and without coexisting hypertension.

PATIENTS AND METHODS

In this open-label, multicentre, uncontrolled, flexible-dose study, 475 men (> or =40 years old) with clinical evidence of BPH were enrolled from 40 centres. Patients were evaluated at baseline and at 1, 2, 6 and 12 months of treatment. The primary efficacy variable was the Clinicians Global Assessment of Change (CGAC; improved, no change, or worse). Secondary efficacy variables were International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urinary flow rate (Q(max)), and postvoid residual (PVR) urine volume. Adverse events (AEs) and blood pressure (BP) were also recorded.

RESULTS

In all, 186 patients completed the study; based on the CGAC, most patients (155, 83.8%) improved and 31 (16.2%) had no change in symptoms. The mean (sd) change in the IPSS and QoL from baseline were -9.0 (6.8) and -1.6 (1.4), respectively (both P < 0.05). The Q(max) and PVR urine volume were significantly better than at baseline, with means of 10.5 (4.3) vs 13.7 (6.3), and 39.1 (37.0) vs 23.2 (33.7); P < 0.05). The decrease in systolic BP (SBP) and diastolic BP (DBP) from baseline in 52 hypertensive patients was significantly greater than in 134 normotensive patients, at (SBP/DBP) -9.5 (18.4)/-13.4 (10.9) vs -3.3 (12.5)/-1.4 (9.5); P < 0.05). A total of 47 AEs were reported in 41 of 475 patients (8.6%); the most common were dizziness (2.7%), erectile dysfunction (1.1%), dry mouth (1.1%), prostatic disorder (0.6%), and postural hypotension (0.4%).

CONCLUSIONS

After 12 months, treatment with doxazosin GITS resulted in an improvement in > 83% of patients based on the CGAC, with significant improvements in IPSS, QoL, Q(max,) and PVR urine volume. Doxazosin GITS was effective and well tolerated as long-term therapy for Korean patients with BPH.

Na+/Li+ and Na+/H+ countertransport activity in hypertensive non-insulin-dependent diabetic patients: role of insulin resistance and antihypertensive treatment

We measured erythrocyte Na+/Li+ and Na+/H+ countertransport (CT) activity (millimoles per liter per cell per hour) in 10 healthy control subjects (age, 38 +/- 4 years; body mass index, 25 +/- 1 kg/m2) and in 25 hypertensive patients with non-insulin-dependent diabetes mellitus ([NIDDM] age, 49 +/- 3 years; body mass index, 29 +/- 1 kg/m2; fasting plasma glucose, 157 +/- 12 mg/dL) 4 weeks after discontinuation of previous antihypertensive treatment. Na+/Li+ CT was significantly increased in hypertensive NIDDM patients compared with controls (0.56 +/- 0.04 v 0.30 +/- 0.03, P < .01), whereas Na+/H+ CT was similar to control levels (21 +/- 1 v 20 +/- 2). A positive correlation was found between Na+/Li+ CT and the severity of insulin resistance (r = .69, P < .01), mean arterial pressure ([MAP] r = .64, P < .01), plasma triglyceride concentration (r = .46, P < .05), and plasma total cholesterol (r = .41, P < .05). An inverse correlation was found between Na+/Li+ CT activity and plasma insulin concentration (r = -.47, P < .05). No relationship was observed between Na+/Li+ CT activity and either creatinine clearance or proteinuria. Stepwise multiple regression analysis for all metabolic variables and blood pressure showed that only the severity of insulin resistance was positively correlated with increased Na+/Li+ CT activity. Na+/H+ and Na+/Li+ CT activity were not altered by 3 hours of euglycemic physiologic hyperinsulinemia (84 +/- 3 microU/mL). Hypertensive NIDDM subjects were treated for 3 months with captopril, nifedipine, or doxazosin. After captopril, a reduction of Na+/H+ CT was observed (22 +/- 4 v 13 +/- 2, P < .05); Na+/Li+ CT decreased after doxazosin (0.56 +/- 0.06 v 0.45 +/- 0.05, P < .05) and nifedipine (0.52 +/- 0.06 v 0.42 +/- 0.05, P < .05). In conclusion, in hypertensive NIDDM subjects, (1) Na+/Li+ CT is increased and is correlated with the level of insulin resistance and the MAP; (2) acute physiologic hyperinsulinemia does not affect Na+/Li+ or Na+/H+ CT activity; and (3) Na+/H+ CT activity is reduced by captopril, and Na+/Li+ CT is decreased by doxazosin and nifedipine.

Synergistic Effect of Doxazosin and Acarbose in Improving Metabolic Control in Patients with Impaired Glucose Tolerance

OBJECTIVE

The aim of this study was to evaluate if the expected improvement in glucose and lipid metabolism obtainable with doxazosin is or is not synergistic with standard antihyperglycaemic treatment using the alpha-glucosidase inhibitor acarbose.

METHODS

Patients in this randomised, controlled, double-blind clinical trial were enrolled, evaluated and followed up at three Italian centres. We evaluated 107 patients (53 males and 54 females) with impaired glucose tolerance (IGT) as determined by oral glucose tolerance tests (OGTTs). All patients took a fixed dose of acarbose 150 mg/day for 3 months, after which they were titrated up to 300 mg/day for the next 3 months. In addition, patients were randomised to either placebo (53 patients: 27 males and 26 females, aged 50 +/- 4 [mean +/- SD] years) or doxazosin 4 mg/day (54 patients: 26 males and 28 females, aged 51 +/- 5 years) for the entire 6-month treatment period. Parameters evaluated during the 6-month treatment period included body mass index (BMI), glycaemic control (glycosylated haemoglobin [HbA(1c)], fasting plasma [FPG] and post-prandial plasma [PPG] glucose, fasting plasma [FPI] and post-prandial plasma [PPI] insulin levels, homeostasis model assessment [HOMA]-index [insulin resistance]), lipid profile (total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides [TG]), and systolic (SBP) and diastolic (DBP) blood pressure.

RESULTS

Significant reductions in BMI, HbA(1c), FPG and PPG compared with baseline were observed after 6 months in both groups (p < 0.05). A significant decrease in FPI was obtained after 6 months (p < 0.05) in the doxazosin group compared with baseline, and this difference was also significant (p < 0.05) compared with the placebo group. Similarly, a significant decrease in HOMA-index was observed at 6 months (p < 0.05) compared with baseline in the doxazosin group, and this difference was also significant (p < 0.05) compared with the placebo group. Significant decreases in TC, LDL-C, HDL-C and TG (p < 0.05) were observed in the doxazosin group after 6 months compared with baseline values. Significant decreases in SBP and DBP were also observed at 3 months in the doxazosin group compared with baseline (p < 0.05), and these differences were significant (p < 0.05) compared with placebo. Furthermore, significant decreases in SBP and DBP were observed at 6 months (p < 0.01) in the doxazosin group compared with baseline, and these differences were also significant (p < 0.01) compared with placebo. All patients who completed an OGTT at 6 months (96 patients) were restored to normal glucose tolerance status.

CONCLUSION

In patients with IGT, doxazosin given in combination with acarbose seemed to improve glycaemic and lipid control compared with placebo, with the benefits observed appearing to extend beyond those expected from improvements in blood pressure. Patients in this study also benefited from acarbose therapy, which restored all patients from IGT to normal glucose tolerance status.

Antihypertensive therapy in renal patients - benefits and difficulties

High blood pressure values, diastolic and systolic, are associated with decreased renal function. This is particularly true when the diastolic blood pressure is higher than 90 mm Hg. Several studies showed that lowering of the blood pressure within the range of normotension according to the WHO causes a reduction in the rate of progression to terminal renal failure. These studies have led to recommendations to aim at a target blood pressure of approximately 125/75 mm Hg in the treatment of patients with glomerular diseases and particularly diabetic nephropathy with proteinuria >1 g/day. In contrast to these results, blood pressure values corresponding to the recommendation (</=125/75 mm Hg) of the JNC VI (see text) were achieved in 15% of the patients only. It has also been shown that at any given level of an average 24-hour blood pressure, patients with an insufficient decrease of the blood pressure during nighttime have a higher risk to progress to terminal renal failure. Thus it is very important to lower the nighttime blood pressure and to detect nighttime blood pressure increases using ambulatory blood pressure measurements.

Effect of time of administration on the pharmacokinetics and tolerance of doxazosin in healthy male volunteers

A randomized, open-label, two-way crossover study of 24 normotensive, healthy male volunteers with nocturia was conducted to compare morning and evening administration of doxazosin in terms of pharmacokinetics and tolerance. In both the morning and evening phases, participants received doxazosin 1 mg once daily for 10 days, followed by 2 mg once daily for 5 days. Pharmacokinetic data were evaluated from blood samples serially collected for 72 hours after drug administration on the last day of each phase. Vital signs and adverse events were recorded throughout the study. Mean peak plasma concentrations (C(max)) were 16.98 and 15.76 ng/mL after morning and evening administration, respectively. Corresponding mean values of area under the plasma concentration-time curve (AUC0-24) were 227.90 and 253.66 ng.hr/mL, respectively. Statistical analysis of the log-transformed values for C(max) and AUC0-24 indicated that morning and evening administration of doxazosin were bioequivalent. There were no statistically or clinically significant differences between phases for mean apparent half-life (t1/2) or total body clearance. There were no clinically relevant differences in blood pressure or in pulse rate between phases, and no occurrences of orthostatic hypotension. The incidence of adverse experiences during morning and evening administration was similar. Morning and evening administration of doxazosin are equivalent and have similar tolerance profiles.

Effect of dosing regimen on efficacy and safety of doxazosin in normotensive men with symptomatic prostatism: a pilot study

OBJECTIVES

In this pilot study, the effect of dosing schedule on the efficacy and safety of the long-acting alpha 1-adrenergic blocker doxazosin (DOX) was evaluated in 48 consecutive, normotensive men (mean age, 61.2 years) with symptoms of prostatism.

METHODS

In this titration to fixed dose study, patients were randomized into 1 of 4 treatment groups: (1) 4 mg DOX once in the AM (n = 12); (2) 4 mg DOX once in the PM (n = 12); (3) 8 mg DOX once in the AM (n = 12); and (4) 8 mg DOX once in the PM (n = 12). Parameters evaluated included Boyarsky symptom score (Sx), peak uroflow (Qmax), blood pressure, and occurrence of side effects. Once stabilized, patients were seen at 3-month intervals; follow-up ranged from 3 to 19 months (mean, 7.7).

RESULTS

Clinical improvement as determined by Sx and Qmax was similar for AM and PM groups with either 4 or 8 mg of DOX. Mean decreases in Sx at 3 months were 4.6, 4.2, 5.1, and 5.2 and at 6 months were 4.7, 4.7, 5.3, and 5.4 for the 4 mg AM, 4 mg PM, 8 mg AM, and 8 mg PM, respectively. Mean peak uroflow at 3 months increased 2.7, 2.9, 3.2, and 3.3 mL/s and at 6 months increased 2.6, 3.0, 3.4, and 3.5 mL/s for the 4 mg AM, 4 mg PM, 8 mg AM, and 8 mg PM, respectively (p < 0.05). Six patients (13%) were dropped from the study because of side effects (2 for fatigue, 2 for headache, 2 for dizziness): 5 during the titration phase (4 mg AM: 2; 8 mg AM: 2; 8 mg PM: 1), and 1 during the treatment phase (8 mg AM).

CONCLUSIONS

These data suggest that evening dosing does not diminish efficacy yet may enhance toleration of DOX. These preliminary results suggest that a larger prospective study is warranted to determine the optimal dosing and timing of DOX in the management of symptomatic benign prostatic hyperplasia.

In vivo administration of doxazosin in rats highly decreases serum circulating levels of testosterone through a mechanism involving the testicular renin–angiotensin system

Men are at greater risk of cardiovascular and renal diseases than women. Several hypertensive rat models also exhibit gender differences in blood pressure. Although the mechanisms responsible for these gender differences are not clear, androgens have been shown to promote hypertension. Testosterone is produced by Leydig cells under the regulation of catecholamines acting through both alpha- and beta-adrenoceptors. Some investigators have postulated a putative role of angiotensin II (Ang II) in modulating the action of gonadotropin in Leydig cells, inhibiting testosterone production. In the present work, we analysed the potential mechanism by which the testicular renin-angiotensin system (RAS) decreases the serum circulating levels of testosterone after the in vivo administration of the long-acting selective alpha(1)-adrenergic receptor antagonist doxazosin. RAS was analysed through assessment of the activity of its proteolytic regulatory enzymes. We can conclude that the testicular testosterone production, at least in rat, is regulated by catecholamines through a mechanism involving alpha(1)-adrenergic receptors and RAS, with a putative role for Ang III. Because doxazosin is usually used as a pharmacological therapy in the treatment of hypertension and benign prostatic hyperplasia, our results could also indicate that its benefits are due, at least in part, to decreased serum circulating levels of testosterone.

Clinical ease of using doxazosin in BPH patients with and without hypertension

Clinical studies have demonstrated that doxazosin therapy reduced blood pressure (BP) in patients with benign prostatic hyperplasia (BPH) who were hypertensive at baseline but not in patients who were physiologically or pharmacologically normotensive at baseline. In patients with BPH and uncontrolled hypertension, despite treatment with other antihypertensive drugs, the addition of doxazosin resulted in improved control with significant reductions in BP. The new formulation, doxazosin gastrointestinal therapeutic system (GITS), is initiated at a therapeutic dose, simplifying dose titration. Based on its efficacy and pharmacokinetic and tolerability profiles, doxazosin GITS is an effective and well-tolerated treatment for normotensive and hypertensive patients with BPH.

The clinical efficacy and tolerability of doxazosin standard and gastrointestinal therapeutic system for benign prostatic hyperplasia

The therapeutic goal of treating benign prostatic hyperplasia (BPH) through early detection and effective therapy is to relieve the symptoms, improve patients' quality of life, decrease postvoid residual urine volume, and prevent the associated morbidity when the condition remains untreated. Alpha1-adrenoreceptor antagonists, e.g. doxazosin, terazosin, tamsulosin and alfuzosin, relax the bladder outlet to improve urinary flow, by reducing prostatic smooth muscle tone through the blockade of sympathetic adrenergic receptors. Doxazosin gastrointestinal therapeutic system (GITS) is a controlled-release formulation developed to enhance the pharmacokinetic profile of the drug while simultaneously minimizing possible adverse effects and reducing the need for dose titration. While both doxazosin standard and GITS are indicated for hypertension, they are also useful in the pharmacologically or naturally normotensive patient with BPH. In a cross-over trial comparing doxazosin GITS and tamsulosin, doxazosin gave a significantly greater improvement from baseline in symptoms. Results from recent trials (e.g. Medical Therapy of Prostatic Symptoms, MTOPS) showed that doxazosin was significantly more effective than the 5alpha-reductase inhibitor finasteride in relieving lower urinary tract symptoms, irrespective of prostate volume. The MTOPS trial showed clearly that over the long term, the combination of doxazosin and finasteride was more effective than either agent alone in significantly improving symptoms and reducing the clinical progression of BPH. Both doxazosin standard and GITS are well-tolerated, long-term therapies that are equally effective in younger and older men, and not associated with causing sexual dysfunction.

LC–MS determination and relative bioavailability of doxazosin mesylate tablets in healthy Chinese male volunteers

This study aims to develop a standard protocol for the relative bioavailability testing of doxazosin mesylate tablets. For this purpose, a simple rapid and selective LC-MS method using a single quadrupole mass spectrometer was developed and validated to determine the concentration of doxazosin mesylate in human plasma. Using this method, we carried out a study of relative bioavailability. N-Hexylane-tertiary butyl methyl ether (1:1, v/v) was used to extract doxazosin mesylate and terazosin (internal standard, I.S.) from an alkaline plasma sample. LC separation was performed on a Thermo Hypersil-Hypurity C18 (5 microm, 150 mm x 2.1mm) using aqueous solution (20 mmol/l ammonium acetate, pH 4.28), methanol and acetonitrile (55:10:35, v/v/v) as the mobile phase. The retention time of doxazosin and the internal standard was 2.7 and 1.8 min, respectively. Quadrupole MS detection was done by monitoring at m/z 388 (M+1) corresponding to doxazosin mesylate and at m/z 452 (M+1) for I.S. The assay method described above showed acceptable precision, accuracy, linearity, stability, and specificity. The bioavailability of doxazosin mesylate was evaluated in 12 healthy Chinese male volunteers. The following pharmacokinetic parameters were elucidated after administering a single dose of 4 mg doxazosin. The area under the plasma concentration versus time curve from time 0 to 72 h (AUC(0-72 h)) 743.4+/-149.5 ngh/ml; peak plasma concentration (C(max)) 47.66 ng/ml; time to C(max) (T(max)) 3.0+/-1.0 h; and elimination half-life (t(1/2)) 18-20 h. The method was successfully used to determine the relative bioavailability of doxazosin mesylate.

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.

Apoptotic and proliferative index after Alpha-1-adrenoceptor antagonist and/or finasteride treatment in benign prostatic hyperplasia

INTRODUCTION

The induction of apoptosis has emerged as a potential target for optimization of the medical management of benign prostatic hyperplasia (BPH), recently. The influence of alpha1-adrenoceptor antagonist (alpha1-ARA), 5-alpha reductase inhibitor and their combination on prostatic cell apoptotic and proliferative indices of benign hyperplastic prostate gland were investigated.

MATERIALS AND METHODS

A total of 49 male patients with BPH (mean age: 66.5 years) treated with alpha1-ARA and/or finasteride were retrospectively evaluated. Patients treated with alpha1-ARA (doxazosin n = 12 and terazosin n = 10), finasteride (n = 9) and combination of finasteride and alpha1-ARA (n = 9) were enrolled in the study. Primary antibodies were Ki-67 and proliferating cell nuclear antigen for the evaluation of proliferation in prostate stromal and epithelial cells. In situ apoptotic DNA fragmentation was evaluated using TUNEL assay.

RESULTS

All treatment groups had no significant changes in the rate of prostate stromal and epithelial cell proliferation. Epithelial apoptotic index (AI) was not statistically significant for finasteride vs. alpha1- ARA, alpha1-ARA vs. finasteride + alpha1-ARA and finasteride + alpha1-ARA vs. finasteride groups. While alpha1-ARA was more effective than finasteride on stromal apoptosis, alpha1-ARA-induced stromal apoptosis was not significantly different from alpha1-ARA plus finasteirde treatment.

CONCLUSION

Not only androgen variabilities but also alterations in sympathetic neurotransmission with age could have important implications for pathophysiological prostate growth. The combination of finasteride and alpha1-ARA is not superior to alpha1-ARA therapy with their similar epithelial and stromal apoptotic effects with unaffected cell proliferation.

Efficacy and safety of tamsulosin hydrochloride compared to doxazosin in the treatment of Indonesian patients with lower urinary tract symptoms due to benign prostatic hyperplasia

AIM

The objective of the study was to compare the efficacy and safety of tamsulosin hydrochloride and doxazosin in patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH).

METHODS

The safety and efficacy of tamsulosin (0.2 mg) and doxazosin (2 mg) was determined after once daily administration for 6 weeks in an open-label, randomized, multicenter study of 101 men with BPH. The International Prostatic Symptom Score (IPSS), maximal urinary flow rates (Qmax), average urinary flow rates (Qave) and residual urine were determined at baseline and again at 6 weeks as efficacy parameters. The primary parameters used for safety evaluation were vital signs (blood pressure and heart rate) and adverse events. The number of patients with a clinically significant response to treatment with tamsulosin or doxazosin was determined and defined as those with >20% improvement from the baseline Qmax or >20% decrease in total IPSS.

RESULTS

The total IPSS decreased significantly in both the tamsulosin and doxazosin groups compared to baseline. There was a significant difference in the decrease in total IPSS between two groups. Qmax, Qave and residual urine significantly improved only in the tamsulosin group. There were no significant differences in systolic blood pressure, diastolic blood pressure or heart rate profile in the tamsulosin group; however, doxazosin resulted in a significant difference in systolic and diastolic blood pressure. Tamsulosin was well tolerated; only three patients (6%) in the tamsulosin group reported an adverse event (dizziness) while 11 patients (22%) in the doxazosin group reported an adverse event (dizziness), one of whom withdrew from the study.

CONCLUSIONS

Tamsulosin was shown to be more effective than doxazosin in the treatment of LUTS due to BPH.

Effect of doxazosin GITS on 24-hour blood pressure profile in patients with stage 1 to stage 2 primary hypertension

OBJECTIVE

To investigate the effect of the doxazosin gastrointestinal therapeutic system (GITS) on the 24 h blood pressure (BP) profile by ambulatory blood pressure measurements (ABPM) in patients with stage 1 to stage 2 primary hypertension.

METHODS AND RESULTS

Seventeen hypertensive patients-either untreated or after a two-week run-in/washout period-underwent office and ABPM monitoring before and six weeks after an open-label once-daily morning dose of 4 mg of doxazosin GITS, an alpha(1)-adrenoceptor antagonist. Fourteen patients responded; three did not. Data analyses refers to the responders: linear analysis demonstrated statistically significant reductions from baseline in daytime, night-time, and total 24 h means for systolic BP (SBP) (7-10 mmHg) and diastolic BP (DBP) (5-10 mmHg) after treatment, with no statistically significant change in heart rate (HR). Rhythm analysis demonstrated statistically significant reductions from baseline in mean mesor (8 mmHg), maximum (6 mmHg) and minimum (10 mmHg) values in SBP, and in mean mesor (5 mmHg), maximum (7 mmHg) and minimum (5 mmHg) values in DBP. Circadian rhythm parameters in BP and HR were not significantly altered by treatment. Treatment with doxazosin GITS was well tolerated.

CONCLUSIONS

A single morning dose of doxazosin GITS at 4 mg significantly reduced ambulatory SBP and DBP throughout a 24 h period while preserving a normal 24 h BP and HR rhythm profile in stage 1 to stage 2 hypertensives.

Alteration of response to neuropeptide Y in the nucleus tractus solitarius of spontaneously hypertensive rats

In normotensive rats, microinjections of neuropeptide Y (2.5 to 25 pmol) into the unilateral nucleus tractus solitarius elicited dose-dependent vasodepressor and bradycardiac responses accompanied by an inhibition of sympathetic nerve firing. After microinjections of the alpha 2-adrenergic receptor antagonist yohimbine (100 ng) into the nucleus tractus solitarius, the depressor and bradycardic responses to the injection of neuropeptide Y (25 pmol) into the nucleus tractus solitarius were significantly attenuated. In contrast, pretreatment with the alpha 1-adrenergic receptor antagonist doxazosin (200 ng) injected into the nucleus tractus solitarius did not alter these responses. In spontaneously hypertensive rats, microinjections of neuropeptide Y (25 pmol) into the nucleus tractus solitarius also elicited depressor and bradycardic responses that were significantly less than those of normotensive Wistar-Kyoto rats. However, pretreatment with yohimbine (100 ng) in the nucleus tractus solitarius did not diminish these depressor responses in spontaneously hypertensive rats. Depressor responses to neuropeptide Y, which was administered after yohimbine pretreatment, were also less in Wistar-Kyoto rats than in spontaneously hypertensive rats. The results suggest that the depressor and bradycardic responses elicited by neuropeptide Y were accompanied by the inhibition of sympathetic nerve activity. These responses may be mediated in part by alpha 2-adrenergic receptor in the nucleus tractus solitarius. The impairment of alpha 2-adrenergic receptor-mediated responses to neuropeptide Y in spontaneously hypertensive rats may contribute to the development of hypertension.

Doxazosin GITS versus hydrochlorothiazide as add‐on therapy in patients with uncontrolled hypertension

The objective of this prospective, randomized, open-label, parallel-arm comparative study, with a 4-month follow-up, was to assess the antihypertensive efficacy, tolerability and metabolic safety of doxazosin GITS (gastrointestinal therapeutic system) 4-8 mg/day vs hydrochlorothiazide (HCTZ) 12.5-25 mg/day as add-on therapy in patients not controlled with monotherapy with other drugs. Ninety-eight patients completed the study (mean age 57.4 +/- 15 years, 53% female). Mean systolic/diastolic blood pressure reduction was 8.2/4.5 mmHg in the HCTZ group and 8.9/5.0 mmHg in the doxazosin GITS group, and a strict blood pressure control was achieved in 79% and 83% of the patients, respectively. The incidence rates of adverse events were low and similar in both groups. However, metabolic differences were seen between the groups, doxazosin GITS vs HCTZ, respectively: total cholesterol (mg/dl) 210 +/- 53 vs 231 +/- 62 (p < 0.05), low-density lipoprotein (LDL) cholesterol (mg/dl) 139 +/- 40 vs 161 +/- 57 (p < 0.01), high-density lipoprotein (HDL) cholesterol (mg/dl) 58 +/- 16 vs 48 +/- 13 (p < 0.01), HDL/total cholesterol ratio 27.6 +/- 8 vs 21.2 +/- 7 (p < 0.001), plasma uric acid (mg/dl) 5.3 +/- 2.6 vs 6.8 +/- 3.1 (p < 0.05) and serum potassium (mEq/l) 4.1 +/- 1.3 vs. 3.7 +/- 1.2 (p < 0.01). In conclusion, doxazosin GITS has a tolerability and efficacy profile similar to low doses of thiazide diuretics, with a better evolution of metabolic and electrolyte parameters. Therefore, in patients not controlled with monotherapy, doxazosin GITS can be considered an alternative to the addition of thiazide diuretics.

Controlled-release doxazosin in the treatment of benign prostatic hyperplasia

PURPOSE

To evaluate the effectiveness and safety of controlled-release doxazosin for benign prostatic hyperplasia (BPH).

SCOPE

In this open-label, noncontrolled, observational surveillance study, 3684 men with BPH received 4-8 mg of controlled-release doxazosin gastrointestinal therapeutic system (GITS) for 6 months; 3283 (89.1%) patients completed the trial. Changes in urinary symptoms and quality of life were assessed using the International Prostate Symptom Score (IPSS). Blood pressure and adverse events were assessed.

CONCLUSION

After 6 months' treatment with doxazosin GITS resulted in significant improvements in IPSS. BP was reduced only in hypertensive patients. Doxazosin, GITS was well tolerated.

Comparison of doxazosin GITS and standard doxazosin in the treatment of high blood pressure

OBJECTIVE

To examine (1) the relative therapeutic equivalence of 4 mg doxazosin gastrointestinal therapeutic system (DOX GITS) and 4 mg doxazosin standard (DOX-S4) and (2) the efficacy and safety of 4 mg DOX GITS versus 2 mg doxazosin standard (DOX-S2).

PATIENTS

Male or female patients aged 18-80 diagnosed with mild-to-moderate essential hypertension (sitting diastolic blood pressure (DBP) 95-110 mmHg and systolic blood pressure (SBP) < 180 mmHg) were randomized into the study.

METHODS

This double-blind, parallel, 9-week trial compared DOX-GITS with doxazosin standard (DOX-S) in 310 hypertensive patients. Following a 2-week placebo run-in phase, patients were randomized to receive DOX-GITS at 4 mg/d or DOX-S at 2 or 4 mg/d. DOX GITS dosage remained unchanged at 4 mg throughout the study. Titration in the DOX-S groups was initiated at Week 0 with 1 mg DOX-S and increased to 2 mg DOX-S at Week 1. Dosage in the DOX-S4 group was increased to 4 mg DOX-S at Week 3. Therapeutic equivalence was measured by the change from baseline in sitting diastolic BP (DBP). Efficacy was assessed using the change from baseline for all blood pressure measures. Safety analysis included evaluation of laboratory tests at clinic visits and adverse events (AEs).

RESULTS

Therapeutic equivalences between DOX GITS and DOX-S4 and DOX-S2 were established at all study visits except for a significant difference in favor of DOX GITS at Week 1 (p = 0.019) when the dose of DOX-S was 1 mg. All groups had a significant decrease in BP at all study visits compared with baseline. The proportion of patients who reached goal sitting DBP (< 90 mmHg) was similar among the three treatment groups, except at Week 1, when more patients in the DOX GITS group had obtained the goal compared with those in the DOX-S2 group (40.6% vs. 22.3%; p = 0.005). The proportion of patients who reached sitting SBP (< 140 mmHg) goal was similar among groups. AE profiles among the groups were similar.

CONCLUSION

DOX GITS was as effective as DOX-S in patients with mild-to-moderate hypertension. The improved pharmacokinetic profile of the GITS formulation compared with the standard formulation allows a therapeutic dose to be delivered earlier and without dose titration. Both formulations of doxazosin were well tolerated.

Safety and efficacy of doxazosin as an "add-on" antihypertensive therapy in mild to moderate heart failure patients

OBJECTIVE

Doxazosin treatment has been discouraged in hypertensive patients in order to prevent heart failure (HF) development. However, this drug is still prescribed as an "add-on" medication to achieve a better blood pressure (BP) control. The aim of this study was to evaluate the safety and efficacy of doxazosin as an "add-on" medication in HF patients with uncontrolled hypertension.

METHODS AND RESULTS

We reviewed our HF clinic files to collect patient variables recorded at baseline and during follow-up visits in patients receiving, or not, doxazosin. We compared HF-related hospitalization rates and all-cause and cardiovascular mortality rates between patients on doxazosin and those not on doxazosin. We constructed cumulative risk curves for time to first event (HF-related hospitalization and/or death) for both groups of patients. Fifty-two HF patients had been prescribed doxazosin. At baseline, several relevant variables were unevenly distributed between patients receiving doxazosin and those not receiving doxazosin (N=122), such as left ventricular ejection fraction (LVEF) and NYHA class. HF-related hospitalization and death rates were similar between patients on doxazosin and those not on doxazosin at the end of the follow-up. Even after adjustment for all potentially confounding variables, doxazosin was not associated with HF-related hospitalization and/or death. Doxazosin significantly reduced BP, but did not affect NYHA class.

CONCLUSIONS

Doxazosin, "on top" of other antihypertensive treatments was safe and effective, and did not appear to be associated with HF-related hospitalization and mortality rates in our patients with mild/moderate HF.

Finasteride and doxazosin alone or in combination for the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia is an increasingly prevalent condition affecting > 50% of men > 65 years of age. Although it is a condition that is unlikely to be life threatening, it can significantly affect quality of life with distressing lower urinary tract symptoms. Increasingly, medical therapy is being used as first-line treatment for men with moderate-to-severe lower urinary tract symptoms. Two main pharmacological classes of drugs are used: 5alpha-reductase inhibitors and alpha-1 selective blockers. Both these classes of drugs have shown good tolerability and clinical efficacy. This article examines the potential benefit of the use of combination therapy. In particular, what is the evidence for using doxazosin and finasteride therapy together?