Doxazosin as combination therapy for patients with stage 1 and stage 2 hypertension

The Subtype Selectivity in Search of Potent Hypotensive Agents among 5,5-Dimethylhydantoin Derived α1-Adrenoceptors Antagonists

In order to find new hypotensive drugs possessing higher activity and better selectivity, a new series of fifteen 5,5-dimethylhydantoin derivatives (1-15) was designed. Three-step syntheses, consisting of N-alkylations using standard procedures as well as microwaves, were carried out. Crystal structures were determined for compounds 7-9. All of the synthesized 5,5-dimethylhydantoins were tested for their affinity to α1-adrenergic receptors (α1-AR) using both in vitro and in silico methods. Most of them displayed higher affinity (Ki < 127.9 nM) to α1-adrenoceptor than urapidil in radioligand binding assay. Docking to two subtypes of adrenergic receptors, α1A and α1B, was conducted. Selected compounds were tested for their activity towards two α1-AR subtypes. All of them showed intrinsic antagonistic activity. Moreover, for two compounds (1 and 5), which possess o-methoxyphenylpiperazine fragments, strong activity (IC50 < 100 nM) was observed. Some representatives (3 and 5), which contain alkyl linker, proved selectivity towards α1A-AR, while two compounds with 2-hydroxypropyl linker (11 and 13) to α1B-AR. Finally, hypotensive activity was examined in rats. The most active compound (5) proved not only a lower effective dose than urapidil but also a stronger effect than prazosin.

Role of α1-blockers in the current management of hypertension

There is emerging evidence that α1-blockers can be safely used in the treatment of hypertension. These drugs can be used in almost all hypertensive patients for blood pressure control. However, there are several special indications. Benign prostatic hyperplasia is a compelling indication of α1-blockers, because of the dual treatment effect on both high blood pressure and lower urinary tract symptoms. Many patients with resistant hypertension would require α1-blockers as add-on therapy. Primary aldosteronism screen is a rapidly increasing clinical demand in the management of hypertension, where α1-blockers are useful for blood pressure control in the preparation for the measurement of plasma aldosterone and renin. Nonetheless, α1-blockers have to be used under several considerations. Among the currently available agents, only long-acting α1-blockers, such as doxazosin gastrointestinal therapeutic system 4-8 mg daily and terazosin 2-4 mg daily, should be chosen. Orthostatic hypotension is a concern with the use of α1-blockers especially in the elderly, and requires careful initial bedtime dosing and avoiding overdosing. Fluid retention is potentially also a concern, which may be overcome by combining an α1-blocker with a diuretic.

Preferred Fourth-Line Pharmacotherapy for Resistant Hypertension: Are We There Yet?

Resistant hypertension (RH) is defined as blood pressure (BP) that remains above target levels despite adherence to at least three different antihypertensive medications, typically including a diuretic. Epidemiological studies estimate that RH is increasing in prevalence, and is associated with detrimental health outcomes. The pathophysiology underlying RH is complex, involving multiple, overlapping contributors including activation of the renin-angiotensin aldosterone system and the sympathetic nervous system, volume overload, endothelial dysfunction, behavioural and lifestyle factors. Hypertension guidelines currently recommend specific pharmacotherapy for 1st, 2nd and 3rd-line treatment, however no specific fourth-line pharmacotherapy is provided for those with RH. Rather, five different antihypertensive drug classes are generally suggested as possible alternatives, including: mineralocorticoid receptor antagonists, α1-adrenergic antagonists, α2-adrenergic agonists, β-blockers, and peripheral vasodilators. Each of these drug classes vary in their efficacy, tolerability and safety profile. This review summarises the available data on each of these drug classes as a potential fourth-line drug and reveals a lack of robust clinical evidence for preferred use of most of these classes in the setting of RH. Moreover, there is a lack of direct comparative trials that could assist in identifying a preferred fourth-line pharmacologic approach and in providing evidence for hypertensive guidelines for adequate treatment of RH.

Doxazosin Stimulates Galectin-3 Expression and Collagen Synthesis in HL-1 Cardiomyocytes Independent of Protein Kinase C Pathway

Doxazosin, a drug commonly prescribed for hypertension and prostate disease, increases heart failure risk. However, the underlying mechanism remains unclear. Galectin-3 is an important mediator that plays a pathogenic role in cardiac hypertrophy and heart failure. In the present study, we investigated whether doxazosin could stimulate galectin-3 expression and collagen synthesis in cultured HL-1 cardiomyocytes. We found that doxazosin dose-dependently induced galectin-3 protein expression, with a statistically significant increase in expression with a dose as low as 0.01 μM. Doxazosin upregulated collagen I and α-smooth muscle actin (α-SMA) protein levels and also induced apoptotic protein caspase-3 in HL-1 cardiomyocytes. Although we previously reported that activation of protein kinase C (PKC) stimulates galectin-3 expression, blocking the PKC pathway with the PKC inhibitor chelerythrine did not prevent doxazosin-induced galectin-3 and collagen expression. Consistently, doxazosin treatment did not alter total and phosphorylated PKC. These results suggest that doxazosin-stimulated galectin-3 is independent of PKC pathway. To determine if the α1-adrenergic pathway is involved, we pretreated the cells with the irreversible α-adrenergic receptor blocker phenoxybenzamine and found that doxazosin-stimulated galectin-3 and collagen expression was similar to controls, suggesting that doxazosin acts independently of α1-adrenergic receptor blockade. Collectively, we show a novel effect of doxazosin on cardiomycytes by stimulating heart fibrosis factor galectin-3 expression. The mechanism of action of doxazosin is not mediated through either activation of the PKC pathway or antagonism of α1-adrenergic receptors.

Simultaneous analysis of vascular norepinephrine and ATP release using an integrated microfluidic system

BACKGROUND

Sympathetic nerves are known to release three neurotransmitters: norepinephrine, ATP, and neuropeptide Y that play a role in controlling vascular tone. This paper focuses on the co-release of norepinephrine and ATP from the mesenteric arterial sympathetic nerves of the rat.

NEW METHOD

In this paper, a quantification technique is described that allows simultaneous detection of norepinephrine and ATP in a near-real-time fashion from the isolated perfused mesenteric arterial bed of the rat. Simultaneous detection is enabled with 3-D printing technology, which is shown to help integrate the perfusate with different detection methods (norepinephrine by microchip-based amperometery and ATP by on-line chemiluminescence).

RESULTS

Stimulated levels relative to basal levels of norepinephrine and ATP were found to be 363nM and 125nM, respectively (n=6). The limit of detection for norepinephrine is 80nM using microchip-based amperometric detection. The LOD for on-line ATP detection using chemiluminescence is 35nM.

COMPARISON WITH EXISTING METHOD

In previous studies, the co-transmitters have been separated and detected with HPLC techniques. With HPLC, the samples from biological preparations have to be derivatized for ATP detection and require collection time before analysis. Thus real-time measurements are not made and the delay in analysis by HPLC can cause degradation.

CONCLUSIONS

In conclusion, the method described in the paper can be used to successfully detect norepinephrine and ATP simultaneously and in a near-real-time fashion.

Doxazosin to treat hypertension: it's time to take it personally--a retrospective analysis of 19, 495 patients

OBJECTIVE

The aim of the current study was to evaluate the effect of α blockers on the cardiac outcomes of hypertensive patients who underwent myocardial perfusion imaging (MPI).

METHODS

A retrospective analysis of the nuclear cardiology laboratory database was performed. The study group included only hypertensive patients (n = 19 ,495). The cohort was divided into three groups - a reference group of no α-blocker therapy (n = 17 ,053), α blockers for benign prostatic hypertrophy (BPH) (n = 1164), and doxazosin for hypertension (HTN) (n = 1258). We used Cox proportional regression models to examine the patient cardiac outcomes (composite of cardiovascular mortality and myocardial infarction) adjusted for the myocardial perfusion study results. The mean age was 65 ± 11.1 years, 55% were men, and the average follow-up was 79.2 ± 37.3 months.

RESULTS

In univariate analysis, the doxazosin for HTN group had the highest rate of adverse cardiac events in comparison to the BPH and reference groups (14.1 vs. 11.3% and 8.9%, respectively, P < 0.001). After stratifying for the degree of reversibility of perfusion defect, only individuals with a moderate-to-severe perfusion defect in the doxazosin for HTN group had a significant increase in adverse cardiac events [hazard ratio 1.50 95% confidence interval (1.14-1.98)].

CONCLUSION

Our data show that doxazosin treatment for HTN is associated with adverse cardiac outcome only among patients with moderate-to-severe ischemia on myocardial perfusion imaging. Doxazosin and other α blockers appear to be safe in the vast majority of patients with a lesser degree of ischemia.

Time to re-appraise the role of alpha-1 adrenoceptor antagonists in the management of hypertension?

The role of alpha-1 adrenoceptor antagonists (alpha-blockers) in the management of hypertension continues to evolve. Recent data support their use as add-on therapy in uncontrolled hypertension when used in combination with all other major classes of antihypertensive drug and there is increasing evidence suggesting that they have modest but significant beneficial effects on lipid and glucose metabolism. The availability of extended-release formulations has contributed to an excellent tolerability profile. New data from an observational analysis of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) suggest that doxazosin gastrointestinal therapeutic system (GITS) used as a third-line antihypertensive agent lowered blood pressure and caused modest reductions in plasma lipids. Furthermore, use of doxazosin in ASCOT was not associated with an increased risk of heart failure, in contrast to the earlier finding of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). Overall, currently available data support the use of alpha-blockers as safe, well tolerated and effective add-on antihypertensive drugs, which have additional favourable metabolic effects.

Comparison of the effects of doxazosin and atenolol on target organ damage in adults with type 2 diabetes mellitus and hypertension in the CARDHIAC study: a 9-month, prospective, randomized, open-label, blinded-evaluation trial

OBJECTIVE

The CARDHIAC (CARduran en pacientes Diabéticos con HIpertensi'on Arterial no Controlada) trial examined the effects of doxazosin gastrointestinal therapeutic system (GITS) and atenolol on 3 separate measures of target-organ damage--left ventricular mass index (LVMI), carotid intima media thickness (IMT), and urinary albumin excretion (UAE)--in patients with type 2 diabetes mellitus and hypertension.

METHOD

This trial had a prospective, open-label, blinded-evaluation design and a duration of 9 months. Patients whose blood pressure (BP) was uncontrolled (systolic BP > or = 130 mm Hg and/or diastolic BP > or = 80 mm Hg) despite at least 1 month of treatment with a renin-angiotensin blocker and diuretic were randomly allocated to receive doxazosin GITS 4 mg or atenolol 50 mg once daily in addition to their existing treatment. Seated BP was measured at study visits at 1, 3, 6 and 9 months; if the BP goal was not achieved at any visit, the dose of doxazosin or atenolol was titrated upward to 8 or 100 mg, respectively. Treatment compliance (pill count) and adverse reactions were monitored at each visit. Each patient underwent echocardiography and Doppler ultrasonography at baseline and at the end of the study for evaluation of the change in LVMI. The change in carotid IMT was evaluated by carotid ultrasound examination at the same time points. UAE also was measured at baseline and the end of the study.

RESULTS

Sixty patients (100% white; 51% female; mean [SD] age, 63.4 [7.5] years; body mass index, 28.2 [3.4] kg/m(2)) were randomized to receive doxazosin GITS (n=32) or atenolol (n=28). At baseline, mean BP was 150.2 (10.6)/90.1 (7.3) mm Hg in the doxazosin group and 153.1 (13.8)/92.3 (6.1) mm Hg in the atenolol group (P=NS). At the end of the study, BP had decreased by 10.1 (3.2)/5.2 (1.3) mm Hg in the doxazosin group and 12.2 (4.2)/6.3 (2.1) mm Hg in the atenolol group (both, P<0.001 vs baseline; P=NS between groups). Heart rate at the end of the study was 78(6) beats/min in the doxazosin group (P=NS vs baseline) and 66(7) beats/min in the atenolol group (P<0.01 vs baseline and between groups). LVMI decreased by 10.8 in the doxazosin group (P=0.001 vs baseline) and 4.2% in the atenolol group (P=NS vs baseline; P=0.03 between groups). The changes in carotid IMT and UAE were not statistically significant between groups.

CONCLUSIONS

In this study in hypertensive patients with type 2 diabetes, LVMI was significantly decreased in doxazosin-treated patients relative to baseline and compared with atenolol-treated patients. The differences in carotid IMT and UAE were not statistically significant between groups.

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.

Add-on therapy with doxazosin in patients with hypertension influences arterial stiffness and albuterol-mediated arterial vasodilation

AIMS

Doxazosin is an antihypertensive agent with largely unknown effects on arterial stiffness and vasodilation. The aim of this study was to determine the effect of the addition of doxazosin extended-release (ER) to the standard management of hypertension in patients with inadequately controlled blood pressure (BP) on arterial stiffness and arterial vasodilation.

METHODS

Twenty patients with inadequately controlled hypertension were treated with 4 mg doxazosin ER daily for 16 weeks as an adjunct to their existing antihypertensive regimen.

RESULTS

Doxazosin ER add-on therapy was associated with significantly reduced systolic (P < 0.0001) and diastolic (P = 0.0003) BP, improved arterial stiffness (determined by digital volume pulse analysis (P = 0.048) and albuterol-mediated arterial vasodilation (P = 0.030).

CONCLUSIONS

Add-on therapy with 4 mg of doxazosin ER daily reduces BP and arterial stiffness and improves arterial vasodilation in response to adrenergic stimulation.

Alpha1-adrenergic blockers: current usage considerations

Alpha1-adrenergic-blocking drugs are effective in reducing blood pressure and do so in a fashion comparable to most other antihypertensive drug classes. These compounds are most effective in patients in the upright position, reducing systolic and diastolic pressures by 8%-10%. Alpha1-adrenergic-blocking drugs incrementally reduce blood pressure when combined with most drug classes and are the only antihypertensive drug class to improve plasma lipid profiles. Alpha1-adrenergic-blocking drugs are also accepted as important elements of the treatment plan for symptomatic benign prostatic hypertrophy. Dose escalation of an alpha1-adrenergic-blocking drug can trigger renal Na+ retention, and the ensuing volume expansion can attenuate its blood pressure-lowering effect. Orthostatic hypotension can occur with these compounds, particularly when a patient is volume-contracted. Dizziness, headache, and drowsiness are common side effects with alpha1-adrenergic blockers. A modest decline in the use of doxazosin and other alpha1-adrenergic-blocking drugs has occurred coincident to the early termination of the doxazosin treatment arm in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial.

Controlled‐Release Doxazosin as Combination Therapy in Hypertension: The GATES Study

Doxazosin gastrointestinal therapeutic system (GITS) or placebo was added to the antihypertensive therapy of uncontrolled hypertensive patients in a prospective, randomized, double-blind trial. Patients received doxazosin GITS 4 mg/d (n=89) or placebo (n=86) for 6 weeks in addition to entry antihypertensive medication. Doxazosin GITS was increased to 8 mg/d after 2 or 4 weeks if patients did not respond (sitting blood pressure <140/90 mm Hg and 10/10-mm Hg decrease from baseline). Reductions from baseline in sitting and standing blood pressures were greater with doxazosin GITS than placebo at all time points (p</=0.017) except Week 1 sitting systolic pressure (p=0.068). The response rate was greater in the doxazosin GITS group (37.3%) than the placebo group (10.7%; p<0.001). With the exception of postural hypotension (7% compared with 0.0%), the frequency of adverse events was similar for doxazosin GITS and placebo. Doxazosin GITS was effective as combination antihypertensive therapy with the major classes of antihypertensive agents.

Effect of Doxazosin on C-Reactive Protein Plasma Levels and on Nitric Oxide in Patients With Hypertension

Inflammation has been hypothesized to play a role in the development of hypertension. The high-sensitivity C-reactive protein (hs-CRP) is a well-studied marker of systemic inflammation that has a predictive power with regard to the development of hypertension. This study was designed to test the hypothesis that hs-CRP plasma levels are altered in hypertension. Moreover, the study was to assess whether chronic antihypertensive treatment with doxazosin would normalize hs-CRP and nitrites/nitrates. We measured plasma levels of hs-CRP and nitrites/nitrates in 44 normotensive subjects and in 44 patients with hypertension before and after doxazosin therapy for 4 months. hs-CRP plasma levels were significantly higher (P < 0.007) in untreated hypertensive group compared to controls. Significant decrease was observed for hs-CRP (P < 0.05) in hypertensive patients after antihypertensive treatment. Nitrites/nitrates were significantly lower (P < 0.0001) in the untreated hypertensive group compared to controls. A significant increase was observed for nitrites/nitrates (P < 0.05) in hypertensive patients after antihypertensive treatment. These results suggest that doxazosin treatment exerts anti-inflammatory effects in addition to its antihypertensive properties in hypertensive patients.

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.

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.

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.