The combination of doxazosin and metyrosine as a preoperative treatment for pheochromocytomas and paragangliomas

PURPOSE

Preoperative medical management is critical to prevent intraoperative cardiovascular complications in patients with pheochromocytomas and paragangliomas (PPGLs). Initial treatment involves α-adrenergic receptor blockers. However, while the routine use of metyrosine alongside these blockers is not strongly recommended due to a lack of evidence supporting its efficacy and associated safety concerns, there are previous studies on combination therapy with phenoxybenzamine and metyrosine. There are few reports on combination therapy with the selective α1-adrenergic receptor blocker doxazosin. Therefore, we investigated this combination treatment, which theoretically can affect perioperative outcomes in patients with PPGLs. To our knowledge, this is the first such study.

METHODS

This retrospective single-center observational study involved 51 patients who underwent surgical resection of PPGLs at Kobe University Hospital between 2014 and 2022. All patients received doxazosin at maximum doses. Fourteen patients received concomitant metyrosine, while 37 received doxazosin alone. Their perioperative outcomes were compared.

RESULTS

No severe event, such as acute coronary syndrome, was observed in either group. Intraoperatively, the doxazosin + metyrosine group exhibited a lower median minimum systolic blood pressure (56 [54-60] vs. 68 [59-74] mmHg, P = 0.03) and required lower median remifentanil (P = 0.04) and diltiazem (P = 0.02) doses than the doxazosin-alone group.

CONCLUSION

The combination of metyrosine and doxazosin as a preoperative treatment for PPGLs affects intraoperative circulatory hemodynamics, such as a reduced occurrence of blood pressure elevation during surgery. Further research is necessary to identify patients who will benefit most from this combination treatment.

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.

Efficacy of α-Blockers on Hemodynamic Control during Pheochromocytoma Resection: A Randomized Controlled Trial

CONTEXT

Pretreatment with α-adrenergic receptor blockers is recommended to prevent hemodynamic instability during resection of a pheochromocytoma or sympathetic paraganglioma (PPGL).

OBJECTIVE

To determine which type of α-adrenergic receptor blocker provides the best efficacy.

DESIGN

Randomized controlled open-label trial (PRESCRIPT; ClinicalTrials.gov NCT01379898).

SETTING

Multicenter study including 9 centers in The Netherlands.

PATIENTS

134 patients with nonmetastatic PPGL.

INTERVENTION

Phenoxybenzamine or doxazosin starting 2 to 3 weeks before surgery using a blood pressure targeted titration schedule. Intraoperative hemodynamic management was standardized.

MAIN OUTCOME MEASURES

Primary efficacy endpoint was the cumulative intraoperative time outside the blood pressure target range (ie, SBP >160 mmHg or MAP <60 mmHg) expressed as a percentage of total surgical procedure time. Secondary efficacy endpoint was the value on a hemodynamic instability score.

RESULTS

Median cumulative time outside blood pressure targets was 11.1% (interquartile range [IQR]: 4.3-20.6] in the phenoxybenzamine group compared to 12.2% (5.3-20.2)] in the doxazosin group (P = .75, r = 0.03). The hemodynamic instability score was 38.0 (28.8-58.0) and 50.0 (35.3-63.8) in the phenoxybenzamine and doxazosin group, respectively (P = .02, r = 0.20). The 30-day cardiovascular complication rate was 8.8% and 6.9% in the phenoxybenzamine and doxazosin group, respectively (P = .68). There was no mortality after 30 days.

CONCLUSIONS

The duration of blood pressure outside the target range during resection of a PPGL was not different after preoperative treatment with either phenoxybenzamine or doxazosin. Phenoxybenzamine was more effective in preventing intraoperative hemodynamic instability, but it could not be established whether this was associated with a better clinical outcome.

Combination Therapy Is Superior to Sequential Monotherapy for the Initial Treatment of Hypertension: A Double-Blind Randomized Controlled Trial

BACKGROUND

Guidelines for hypertension vary in their preference for initial combination therapy or initial monotherapy, stratified by patient profile; therefore, we compared the efficacy and tolerability of these approaches.

METHODS AND RESULTS

We performed a 1-year, double-blind, randomized controlled trial in 605 untreated patients aged 18 to 79 years with systolic blood pressure (BP) ≥150 mm Hg or diastolic BP ≥95 mm Hg. In phase 1 (weeks 0-16), patients were randomly assigned to initial monotherapy (losartan 50-100 mg or hydrochlorothiazide 12.5-25 mg crossing over at 8 weeks), or initial combination (losartan 50-100 mg plus hydrochlorothiazide 12.5-25 mg). In phase 2 (weeks 17-32), all patients received losartan 100 mg and hydrochlorothiazide 12.5 to 25 mg. In phase 3 (weeks 33-52), amlodipine with or without doxazosin could be added to achieve target BP. Hierarchical primary outcomes were the difference from baseline in home systolic BP, averaged over phases 1 and 2 and, if significant, at 32 weeks. Secondary outcomes included adverse events, and difference in home systolic BP responses between tertiles of plasma renin. Home systolic BP after initial monotherapy fell 4.9 mm Hg (range: 3.7-6.0 mm Hg) less over 32 weeks (P<0.001) than after initial combination but caught up at 32 weeks (difference 1.2 mm Hg [range: -0.4 to 2.8 mm Hg], P=0.13). In phase 1, home systolic BP response to each monotherapy differed substantially between renin tertiles, whereas response to combination therapy was uniform and at least 5 mm Hg more than to monotherapy. There were no differences in withdrawals due to adverse events.

CONCLUSIONS

Initial combination therapy can be recommended for patients with BP >150/95 mm Hg.

CLINICAL TRIAL REGISTRATION

URL: http://www.ClinicalTrials.gov. Unique identifier: NCT00994617.

Effect of doxazosin on stress reactivity and the ability to resist smoking

Preclinical findings support a role for α1-adrenergic antagonists in reducing nicotine-motivated behaviors, but these findings have yet to be translated to humans. The current study evaluated whether doxazosin would attenuate stress-precipitated smoking in the human laboratory. Using a well-validated laboratory analogue of smoking-lapse behavior, this pilot study evaluated whether doxazosin (4 and 8 mg/day) versus placebo attenuated the effect of stress (vs neutral imagery) on tobacco craving, the ability to resist smoking and subsequent ad-libitum smoking in nicotine-deprived smokers ( n=35). Cortisol, adrenocorticotropin, norepinephrine, epinephrine, and physiologic reactivity were assessed. Doxazosin (4 and 8 mg/day vs placebo) decreased cigarettes per day during the 21-day titration period. Following titration, doxazosin (4 and 8 mg/day vs placebo) decreased tobacco craving. During the laboratory session, doxazosin (8 mg/day vs placebo) further decreased tobacco craving following stress versus neutral imagery. Doxazosin increased the latency to start smoking following stress, and reduced the number of cigarettes smoked. Dosage of 8 mg/day doxazosin increased or normalized cortisol levels following stress imagery and decreased cortisol levels following neutral imagery. These preliminary findings support a role for the noradrenergic system in stress-precipitated smoking behavior, and support further development of doxazosin as a novel pharmacotherapeutic treatment strategy for smoking cessation.

Influence of doxazosin on biosynthesis of S100A6 and atrial natriuretic factor peptides in the heart of spontaneously hypertensive rats

Hypertension frequently results in severe complications in cardiovascular system and histopathological changes in the heart. To better understand the cellular processes and signaling pathways responsible for the proper functioning of the heart, we decided to check whether doxazosin affects the density of structures containing S100A6 and atrial natriuretic factor in the heart of spontaneously hypertensive rats. The aim of this study is to find differences in the density of the structures containing S100A6 and atrial natriuretic factor in the heart of spontaneously hypertensive rats treated with doxazosin compared to untreated animals. Fragments of heart were collected from five spontaneously hypertensive rats and five spontaneously hypertensive rats receiving doxazosin for six weeks (dose 0.1 mg per 1 kg of body weight). On the paraffin sections S100A6 and atrial natriuretic factor peptides were localized in the heart using immunohistochemistry. Positive immunohistochemical reaction for S100A6 was observed in atrial and ventricular cardiomyocytes and in the coronary vasculature. In the heart of hypertensive rats treated with doxazosin the S100A6 immunoreactivity was significantly lower compared to untreated animals. Immunodetection of atrial natriuretic factor in the heart of rats confirmed presence of peptide in atrial myocardium. Delicate atrial natriuretic factor-immunoreactivity was observed also in few ventricular cardiomyocytes. The atrial natriuretic factor-immunosignal was significantly weaker in hearts of hypertensive rats receiving doxazosin compared to spontaneously hypertensive rats untreated. Since we found that doxazosin reduces the levels of S100A6 and atrial natriuretic factor peptides in the heart of spontaneously hypertensive rats, it can be assumed that cardiovascular disorders that occur in hypertension may be associated with disturbances of cellular processes and signaling pathways.

Determination of the efficiency of 8 mg doxazosin XL treatment in patients with an inadequate response to 4 mg doxazosin XL treatment for benign prostatic hyperplasia

OBJECTIVE

To compare the efficacy of 4 mg and 8 mg doxazosin XL treatments in patients with benign prostatic hyperplasia-related lower urinary tract symptoms and determine the efficiency of 8 mg in those patients with inadequate response to 4 mg.

METHODS

A total of 162 patients were included in this study. Of the patients, 108 were randomized to receive 4 mg doxazosin XL (group 1), and 54 were randomized to receive 8 mg (group 2) treatments. After 1 month of treatment, 31 patients in group 1 whose quality of life (QoL) score was unchanged or had deteriorated were switched to 8 mg doxazosin XL treatment (group 1b).

RESULTS

The mean age was 59.8 years. After 1 month of treatment, the mean alteration in the International Prostate Symptom Score was 3.9 and 5.2 (P = .028), for the maximum urinary flow rate (Q(max)), it was 3.0 and 3.6 mL/s (P = .206), and for the QoL score it was 1.3 and 1.7 (P = .038) in groups 1 and 2, respectively. For group 1b, during the period in which the patients were receiving 4 and 8 mg doxazosin XL treatments; the International Prostate Symptom Score changes were 1.3 and 3.6 (P <.001), the Q(max) changes were 1.6 and 3.2 mL/s (P <.019), and the QoL changes were 0.4 and 1.8 (P <.001) in groups 1 and 2, respectively.

CONCLUSION

With no changes in side effects, 8 mg doxazosin XL treatment is an efficient choice for patients who did not have an adequate response to 4 mg doxazosin XL treatment.

Pulse release of doxazosin from hydroxyethylcellulose compression coated tablet: mechanistic and in vivo study

Chronotherapeutically programmed hydroxyethylcellulose (HEC) based compression coated doxazosin tablets were prepared and the influence of disintegrants croscarmellose sodium, L-hydroxypropylcellulose (L-HPC), gellan gum on drug release and in vivo performance were investigated. Infrared spectroscopy and differential scanning calorimetric studies did not indicate any excipient incompatibility in the tablets. The disintegrants induced a continuous water influx resulting in a rapid expansion of the membrane. The subsequent formation of fractures into the coats leads to a fast drug release after an initial lag time. Release rates indicated that croscarmellose sodium and L-HPC were directly proportional to their concentration in the formulations. In vitro optimized croscarmellose sodium-HEC matrix showed significantly faster (p < 0.05) drug release (t90% = 46 min) after an initial lag of 243 min. Disintegrant-HEC blended matrices were found significantly superior (p < 0.05) in terms of in vitro release and bioavailability in comparison to plain HEC matrices. Drug release kinetics followed modified power law and Weibull model (r > 0.99). The mechanism involved in release was anomalous transport and super case II transport with matrix swelling. The pulsatile tablets showed no changes either in physicochemical appearance, drug content or in dissolution pattern during its accelerated stability studies.

(-)Doxazosin is a necessary component for the hypotensive effect of (±)doxazosin during long-term administration in conscious rats

AIM

Doxazosin is a racemic mixture of (-)doxazosin and (+)doxazosin that is currently used as an add-on therapy for hypertension. In this study we investigated the contribution of each enantiomer to the hypotensive action of long-term administration of (±)doxazosin in conscious rats.

METHODS

Blood pressure of conscious SD rats was measured using a volume pressure recording system. The rats were orally administered (-)doxazosin, (+)doxazosin, or (±)doxazosin (8 mg·kg(-1)·d(-1)) for 12 weeks. Plasma concentrations of the agents were analyzed with HPLC. The effect of the agents on α1-adrenoceptor was examined in isolated rat caudal artery preparations.

RESULTS

Treatment of conscious rats with a single dose of (±)doxazosin (8 mg/kg) did not affected DBP and MBP, but significantly decreased SBP by 11.9% 4 h after the administration. Long-term treatment of conscious rats with (±)doxazosin significantly decreased SBP, DBP and MBP with a maximal decrease of SBP by 29.3% 8 h after the last administration. The rank order of the hypotensive actions caused by long-term treatment in conscious rats was (±)doxazosin>(+)doxazosin>>(-)doxazosin. However, the pKB values for inhibiting NA-induced contraction of isolated rat caudal artery were (+)doxazosin (8.995)>(±)doxazosin (8.694)>(-)doxazosin (8.032). The plasma concentrations of (-)doxazosin, (+)doxazosin, and (±)doxazosin were 18.26±3.55, 177.11±20.66, and 113.18±13.21 ng/mL, respectively, 8 h after the last administration of these agents.

CONCLUSION

Long-term treatment with (±)doxazosin produces potent hypotensive action in conscious rats that seems to result from synergic interaction of the two enantiomers.

[Features of neurohumoral regulation in children with combined dysfunction of the pelvic organs]

During examination of 165 children aged 5 to 15 years (primarily identified during planned monitoring in Petrozavodsk children's institutions) with dysfunctional urination and encopresis without organic lesion of the central nervous system, autonomic dysfunction syndrome (ADS) was revealed. According to the results of urological examination, which was supplemented with the registration of spontaneous voiding rate and counting the radial pulse, overactive bladder syndrome and insufficient relaxation of the pelvic floor muscles during urination and defecation were detected; relationship between the number of heart rate (as a marker of sympathetic nervous system activity) and the effective volume was identified. It was revealed that the children with ADS in the presence of tachycardia show intermittent decrease of effective amounts of urination, and have residual urine. The standard course of treatment using colon hydrotherapy and biofeedback to activate cystic and obturator reflex caused a positive but short-term therapeutic effect; clinically and statistically significant increase in the effective volume of the bladder was not achieved, despite the reduction in residual urine volume. During the course of treatment using methods of biofeedback, bladder volume remained almost unchanged and tachycardia persisted, indicating the continued oppression of the sympathetic activity. The course of treatment using nootropic drug picamilon and alpha-adrenoblocker doxazosin with peripheral actions allowed to restore the reservoir and evacuation functions of the bladder, to achieve a regular bowel movement without encopresis. It was revealed that the combined dysfunction of pelvic organs occur in children with high activity of the sympathetic division of the ANS, which has a direct impact on the accumulation phase of voiding cycle and relaxation of the pelvic floor muscles.

Role of preoperative adrenergic blockade with doxazosin on hemodynamic control during the surgical treatment of pheochromocytoma: a retrospective study of 48 cases

Authors evaluated the effects of selective adrenergic blockade by means of doxazosin on blood pressure in 48 patients operated on for pheochromocytoma by a multicenter retrospective study. Age, tumor size, surgical approach, and operative time were analyzed as predictive factors of intraoperative hypertensive crises. Forty-eight patients underwent adrenalectomy--four open surgery and 44 laparoscopic surgery--for pheochromocytoma of adrenal glands from 1998 to 2008 after preoperative administration of doxazosin. Perioperative cardiovascular status modifications and surgical medium- and long-term outcomes were analyzed. There was no mortality, conversion rate was 4.5 per cent, and morbidity rate was 8.3 per cent. Intraoperative hypertensive crises (180/90 mmHg or higher) were observed in 14.5 per cent (seven of 48) of patients and were treated pharmacologically with no aftermath. None of the examined variables influenced the occurrence of intraoperative hypertensive episodes. Postoperative hypotension (lower than 90/60 mmHg) was observed in four of 48 patients (8.3%) and was treated by crystalloids and hydrocortisone. In the surgical treatment of pheochromocytoma, the preoperative adrenergic blockade by doxazosin does not prevent intraoperative hypertensive crises. Nevertheless, in our series, they were of short duration and were not associated with major cardiovascular complications. Perioperative hemodynamic instability was managed by preoperative pharmacological treatment, allowing low morbidity.

Comparing the effectiveness of intranasal desmopressin and doxazosin in men with nocturia: a pilot randomized clinical trial

PURPOSE

We aimed to compare the effectiveness of intranasal desmopressin and doxazosin treatments in patients with nocturia and benign prostatic hyperplasia (BPH).

MATERIAL AND METHODS

Thirty one men with BPH and three or more episodes of nocturia were randomized to receive 2 mg doxazosin at night for two weeks increasing to 4 mg for a further two weeks versus 20 μg intranasal desmopressin at night. For all patients, number of nocturia, urinary flow rate, residual urine volume and quality of life score were checked. Outcomes were measured at two months. The comparison of before and after treatment changes between the groups were done by student's t-test.

RESULTS

In doxazosin group, mean number of nocturia were 3.2 &plus mn; 0.4 (3-4 times) times per night and 1.2 +/- 0.8 (0-3 times) times per night before and after treatment, respectively. In desmopressin group, mean number of nocturia were 3.4 +/- 0.5 (3-4 times) and 1.5 +/- 0.6 (1-3 times) times per night before and after treatment, respectively. In doxazosin group, mean residual urine volumes were 44.3 +/- 35.9 ml (range 0-120 ml) and 23.1 +/- 18.8 ml (range 0-50 ml) before and after treatment, respectively. In desmopressin group, mean residual urine volumes were 36.6 +/- 32.4 ml (range 0-120 ml) and 14.0 +/- 26.9 ml (range 0-90 ml) before and after treatment, respectively. Improvements in number of nocturia, residual urine volume, quality of life scores and peak urinary flow rates weren't statistically significant between two groups, whereas change in international prostate symptom score (IPSS) score was more significant in doxazosin group.

CONCLUSION

Intranasal desmopressin, is an effective symptomatic treatment of men with BPH complaining of nocturia, as well as doxazosin treatment.

[Combined treatment of patients with lower urinary tract symptoms and erectile dysfunction]

In men of middle and older age group, urination disorders and erectile dysfunction are often combined. The role of phosphodiesterase type 5 inhibitors in the treatment of these patients remains uninvestigated. Prospective study included 38 patients with urination disorders and erectile dysfunction. The average age of the patients was 63.6 +/- 5.3 years. During first three months of observation, all patients have received alpha-adrenoblocker doxazosin at a dose of 4 mg once daily per os, the next three months--phosphodiesterase type 5 inhibitor udenafil at a dose of 50 mg once daily per os was added to doxazosin. 3 months after treatment, majority of patients reported improvement of urination. The statistically significant changes in BP and heart rate were not recorded, indicating a satisfactory tolerability and safety of doxazosin. Against the background of combined treatment during next 3 months, progressive improvement of erectile function (IIEF score 12.8 +/- 3.4 vs 18.4 +/- 3.7; p < 0.05), and regression of urination disorders, according to IPSS score (13.4 +/- 1.2 vs 11.2 +/- 1.7; p < 0.05) were observed. Uroflowmetric indicators were not significantly changed. Based on experimental and clinical studies, it was suggested that the dysregulation of NO--cGMP system, pathological activation of Rho-kinase pathways, hyperactivity of autonomic innervation, atherosclerosis and impaired blood flow in the pelvic organs are the common pathophysiological mechanisms for LUTS and erectile dysfunction. The clinical efficacy of phosphodiesterase type 5 inhibitors in the treatment of patients with these diseases is explained by its effects on these mechanisms.

[Experience of the use of silodosin in acute urinary retention caused by benign prostatic hyperplasia]

For the treatment of acute urinary retention (AUR) as one of the most serious complications of adenoma of the prostate (BPH), alpha-adrenoblockers are widely used. The article presents an experience of the use of the new uroselective alpha-adrenoblocker silodosin approved for the treatment of patients with urination disorders caused by BPH. Its pharmacological profile has a number of advantages, including the highest uroselectiveness at the present day, immediate action, the potential for the use of standard dose of 8 mg 1 time a day, which does not require a correction depending on the age, and the possibility of the simultaneous application with antihypertensive drugs.

[Results of open multicenter study of the safety of doxazosin in combination with indigal in men with stages I-II prostatic adenoma]

The article presents a method of conservative treatment of men with I-II stage prostatic adenoma using a combination of doxazosin and indigal, which has antioxidant, antiproliferative and anti-inflammatory properties, that allowed improving urodynamic parameters and reducing the progression prostate adenoma, minimizing the adverse effects of 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.

Cholinergic stimulation of adrenal medulla is essential for the granulicytopoietic response to lithium

Granulocytopoietic response to lithium carbonate (Li+) in rat was eliminated completely by N-cholinergic blocking agent, and independently by alpha-1-adrenergic antagonist. A link between these two contradictory events is explained by release of acetylcholine from the cholinergic preganglionic nerve endings in adrenal medulla triggered by Li+, and subsequent discharge of catecholamines (CA) from medullar chromaffin cells, which on their part activate adrenergic receptors of alpha-1 class on hematopoietic progenitor cells. Respectively, granulocytopoietic response to Li+ is blocked by cholinergic N-blocking agent at the level of adrenal medulla, and by the alpha-adrenergic blocking agent at the level of the hematopoietic cells proper. The stimulatory action of Li+ on granulocytopoietic cells is indirect, while is mediated by CA release from adrenal chromaffine cells. At the initial stages of leukocyte restitution in the acute myelotoxic leucopenia relative increase in "large" lymphocyte fraction (Lge) preceding the increment in granulocyte counts is evident. In this fraction of lymphocytes peripheral blood progenitor cells (PBPC) are expected.

Noradrenergic α₁ receptor antagonist treatment attenuates positive subjective effects of cocaine in humans: a randomized trial

Background

Preclinical research implicates dopaminergic and noradrenergic mechanisms in mediating the reinforcing effects of drugs of abuse, including cocaine. The objective of this study was to evaluate the impact of treatment with the noradrenergic α₁ receptor antagonist doxazosin on the positive subjective effects of cocaine.

Methods

Thirteen non-treatment seeking, cocaine-dependent volunteers completed this single-site, randomized, placebo-controlled, within-subjects study. In one study phase volunteers received placebo and in the other they received doxazosin, with the order counterbalanced across participants. Study medication was masked by over-encapsulating doxazosin tablets and matched placebo lactose served as the control. Study medication treatment was initiated at 1 mg doxazosin or equivalent number of placebo capsules PO/day and increased every three days by 1 mg. After receiving 4 mg doxazosin or equivalent number of placebo capsules participants received masked doses of 20 and 40 mg cocaine IV in that order with placebo saline randomly interspersed to maintain the blind.

Results

Doxazosin treatment was well tolerated and doxazosin alone produced minimal changes in heart rate and blood pressure. During treatment with placebo, cocaine produced dose-dependent increases in subjective effect ratings of “high”, “stimulated”, “like cocaine”, “desire cocaine”, “any drug effect”, and “likely to use cocaine if had access” (p<.001). Doxazosin treatment significantly attenuated the effects of 20 mg cocaine on ratings of “stimulated”, “like cocaine”, and “likely to use cocaine if had access” (p<.05). There were trends for doxazosin to reduce ratings of “stimulated”, “desire cocaine”, and “likely to use cocaine if had access” (p<.10).

Conclusions

Medications that block noradrenergic α₁ receptors, such as doxazosin, may be useful as treatments for cocaine dependence, and should be evaluated further.

Trial Registration

Clinicaltrials.gov NCT01062945

[Clinical efficacy of a short-term regimen of Cardura XL on lower urinary tract symptoms and international prognostic scoring system in the treatment of benign prostatic hyperplasia]

OBJECTIVE

To evaluate the clinical efficacy of Cardura XL (doxazosin mesylate controlled release tablets) on lower urinary tract symptoms, IPSS (international prognostic scoring system) and short-term QOL (quality of life) (3 months) in the treatment of benign prostatic hyperplasia (BPH).

METHODS

From July 2008 to February 2009, 80 male BPH patients with a mean age of 70.5 years old (range: 62-82) were prospectively recruited to receive a daily dose of Cardura XL 4 mg for 3 months. Clinical parameters of IPSS QOL, Qmax (maximum flow rate), residual urine, blood pressure and heart rate were recorded before and 3 months after treatment. Paired t test was performed on the corresponding data. And therapeutic efficacy and side effects were analyzed according to the statistical results.

RESULTS

All 80 patients finished a 3-month medical regimen. Between pre-treatment and 3 months after medication, paired t test was performed on the corresponding data of maximum flow rate (Qmax), residual urine, IPSS, QOL, blood pressure and heart rate. Significant differences were observed in all corresponding data (P < 0.001) except heart rate (P = 0.685). Furthermore analyses were performed on the corresponding IPSS and QOL between one month and 3 months after treatment. Significant improvement was also observed in IPSS and QOL after a longer medication (P < 0.001). Transient side effects were observed in 16 patients (20%): headache (n = 8, 10%), fatigue (n = 4, 5%) and dizziness (n = 4, 5%). No patient withdrew from the study.

CONCLUSION

Cardura XL, at a daily dose of 4 mg daily for 3 months, is a safe and effective regimen in BPH patients. Significant improvement is observed for lower urinary tract symptoms, IPSS and QOL. A longer medication may lead to further improvement of IPSS and QOL. After dosing, both systolic and diastolic blood pressures fall down significantly. No significant effect on heart rate is found. And most patients have an excellent tolerance.

Selective α1-adrenoceptor antagonist (controlled release tablets) in preoperative management of pheochromocytoma

The objective of this article is to evaluate the efficacy of Doxazosin Mesylate Controlled Release Tablets for preoperative treatment of patients with pheochromocytoma. Between 2003 and 2008, 67 patients with confirmed diagnoses of pheochromocytoma were enrolled in this study. According to the drug used in preoperative management, patients were divided into two groups: Doxazosin Mesylate pretreatment group (n=36) and Phenoxybenzamine pretreatment group (n=31). Surgery was performed only in patients who met the optimal preoperative condition. The hematocrit decreased significantly (P<0.001) after antiadrenergic therapy in patients pretreated with phenoxybenzamine or doxazosin. There was no significant difference between the fluid intakes during operation in both groups. The systolic arterial pressures both before and after induction of anesthesia were all significantly higher in the doxazosin patients than in the phenoxybenzamine group (P<0.05). After tumor removed, the lowest systolic arterial pressure was significantly higher in doxazosin group than in phenoxybenzamine group (P<0.05). The fluctuation of systolic arterial pressure during operation was more stable in doxazosin group than in phenoxybenzamine group (P<0.05). Doxazosin mesylate controlled release tablet was as effective as phenoxybenzamine in preoperative volume expansion. Although phenoxybenzamine provided better arterial pressure control, patients pretreated with DOX experienced more stable perioperative hemodynamic changes, shorter preoperative management periods and more simple medication.

Interactions of biopolymers carrageenans with cationic drug doxazosin mesylate characterized by means of differential scanning calorimetry

When ionic polymers (polyelectrolytes) are used as excipients in pharmaceutical formulations, the properties of oppositely charged drugs may be strongly affected by the charge-charge interactions or complex formation. Usually these effects are considered as a negative event resulting in a drug-excipient incompatibility. Sometimes ionic interactions are preferred to prolong drug release from dosage forms in a controllable manner. Ionic interactions of carrageenans with doxazosin mesylate were confirmed by differential scanning calorimetry (DSC). Evident peak shifts and shape changes of assumed desulfation peak of carrageenans in concordance with disappearance of melting peak of doxazosin mesylate (DM) in DSC curves were obtained. The range of thermal effects is depended on the ratio of doxazosin mesylate and carrageenans. The higher the ratio of DM compared to CARRs the more evident are the interactions.

[Anesthetic management of a patient with pheochromocytoma and end-stage renal disease]

We experienced anesthesia of a patient with pheochromocytoma on chronic hemodialysis who developed severe hypotension resistant to vasopressors after induction of general anesthesia. She was presented for spine surgery for destructive arthropathy of the cervical spine. Doxazosin up to 0.5 mg x day(-1) was administered for five days preoperatively for alpha-adrenergic blokade and regular hemodialysis was continued until the day before surgery without change in dry body weight. Blood pressure (BP) was within normal limits preoperatively. After induction of anesthesia with propofol and fentanyl, the patient developed hypotension with systolic BP of 60 mmHg which was resistant to vasopressor treatment with phenylephrine and ephedrine. After 45 minutes of volume replacement and commencement of dopamine and norepinephrine administration via a central venous catheter, BP recovered, and the surgery proceeded without further incident. Hypertension due to pheochromocytoma can be masked by excessive reduction of intravascular volume by preoperative hemodialysis. In a hemodialysed patient harboring pheochromocytoma who undergoes a surgical procedure unrelated to adrenalectomy, preoperative alpha-adrenergic blockade and subsequent intravascular volume expansion by increasing dry weight is required to avoid severe intraoperative hypotension, as for the case of adrenalectomy in the same situation.

Administration-Time-Dependent Effects of Doxazosin GITS on Ambulatory Blood Pressure of Hypertensive Subjects

Previous studies have shown that a single nighttime dose of standard doxazosin, an alpha-adrenergic antagonist, reduces blood pressure (BP) throughout the 24 h. We investigated the administration-time-dependent effects of the new doxazosin gastrointestinal therapeutic system (GITS) formulation. We studied 91 subjects (49 men and 42 women), 56.7+/-11.2 (mean+/-SD) yrs of age with grade 1-2 essential hypertension; 39 patients had been previously untreated, and the remaining 52 had been treated with two antihypertensive medications with inadequate control of their hypertension. The subjects of the two groups, the monotherapy and polytherapy groups, respectively, were randomly assigned to receive the single daily dose of doxazosin GITS (4 mg/day) either upon awakening or at bedtime. BP was measured by ambulatory monitoring every 20 min during the day and every 30 min at night for 48 consecutive hours just before and after 3 months of treatment. After 3 months of doxazosin GITS therapy upon awakening, there was a small and nonstatistically significant reduction in BP (1.8 and 3.2mm Hg in the 24 h mean of systolic and diastolic BP in monotherapy; 2.2 and 1.9mm Hg in polytherapy), mainly because of absence of any effect on nocturnal BP. The 24 h mean BP reduction was larger and statistically significant (6.9 and 5.9 mm for systolic and diastolic BP, respectively, in monotherapy; 5.3 and 4.5 mm Hg in polytherapy) when doxazosin GITS was scheduled at bedtime. This BP-lowering effect was similar during both the day and nighttime hours. Doxazosin GITS ingested daily on awakening failed to provide full 24h therapeutic coverage. Bedtime dosing with doxazosin GITS, however, significantly reduced BP throughout the 24h both when used as a monotherapy and when used in combination with other antihypertensive pharmacotherapy. Knowledge of the chronopharmacology of doxazosin GITS is key to optimizing the efficiency of its BP-lowering effect, and this must be taken into consideration when prescribing this medication to patients.

[Efficacy of combined treatment of large prostatic adenoma with doxasozine and finasteride]

Combined treatment with doxasozine and finasteride was performed for 7.26 months in 38 patients with large-size prostatic adenoma (89.54 +/- 11.64 cm3). The study group of 38 patients given the above combination benefited from the treatment (18 patients avoided surgery, TUR of shorter duration with removal of a less amount of tissue and less blood loss was conducted in 20 patients). Bladder draining with the urethral catheter was also shorter in the study group. The control group (28 patients with large prostatic adenoma) received surgical treatment alone. Long-term results were good in both the groups. Thus, combined treatment with doxasozine and finasteride can be the first-line treatment in patients with large prostatic adenoma.

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.

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.

[Efficacy and safety of doxazosine in combination with finasteride in the treatment of prostatic adenoma]

Clinical effects and safety of doxazosine + finasteride combination were studied in patients with obstructive and irritative symptoms due to prostatic adenoma (PA). Lower urinary tract symptoms according to IPSS, size of the prostatic gland, Qmax and Qmid, bladder capacity, residual urine volume, blood pressure, PSA level, sexual function, side effects were assessed before and after combined use of the drugs in 30 patients aged 58 to 83 years (mean age 70.5 years). A significant regression of both obstructive and irritative symptoms by IPSS occurred after the treatment. Quality of life has improved. Combined treatment of PA patients has improved quality of life, urination parameters, reduced volume of residual urine. Good tolerance of the treatment was observed. Combined therapy with doxazosine and finasteride can be recommended as a basic scheme of treatment for patients with risk of PA progression.

Pharmacokinetics of Doxazosin Gastrointestinal Therapeutic System after Multiple Administration in Korean Healthy Volunteers

Doxazosin mesylate is a selective alpha-adrenoreceptor antagonist for the treatment of hypertension and benign prostatic hyperplasia. A simple high performance liquid chromatographic method has been developed and validated for the quantitative determination of doxazosin in plasma. A reversed phase C18 column was used for the separation of doxazosin and prazosin (internal standard) with a mobile phase composed of water, acetonitrile, triethylamine (68:32:0.2 v/v, pH 5.0) at a flow rate of 1.2 mL/min. The fluorescence detector was operated at 246 (excitation) and 389 nm (emission). Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification of 1 ng/mL. Recovery of doxazosin from human plasma was greater than 93.4%. Doxazosin was stable in human plasma under various storage conditions. This method was used successfully for a pharmacokinetic study in plasma after oral administration of multiple 4-mg dose of doxazosin gastrointestinal therapeutic system formulation to 16 healthy volunteers. At steady state the mean area under the curve for a dosing interval and elimination half-life were calculated to be 367.0 +/- 63.5 ng x hr/mL and 29.2 +/- 4.5 hr, respectively. There was no difference in pharmacokinetic parameters between male and female.

Bioequivalence Evaluation of Two Formulations of Doxazosin Tablet in Healthy Thai Male Volunteers

The bioequivalence of two doxazosin 2 mg tablets was determined in 24 healthy Thai male volunteers after one single dose in a randomized cross-over study with a one week washout period. The study was conducted at Faculty of Pharmaceutical Sciences and Health Sciences Research Institute, Naresuan University, Phitsanulok, Thailand. Reference (Cardura, Heinrich Mack Nachf. GmbH & Co. GK, Illertissen, Germany) and test (Dozozin-2, Umeda Co., Ltd., Bangkok Thailand) were administered to volunteers after overnight fasting. Blood samples were collected at specified time intervals and plasma was separated. The validated HPLC method with fluorescence detection was used for quantification of doxazosin in plasma samples. The pharmacokinetic parameters, T(max), C(max), AUC(t), AUC(infinity), T(1/2), lambda(z), Cl and V(d), were determined from plasma concentration time profile of both formulations by using non-compartment analysis. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands. The analysis of variance (ANOVA) using log-transformed C(max), AUC(t), and AUC(infinity) did not show any significant difference between two formulations. The point estimates and 90% confidence intervals for C(max), AUC(t) and AUC(infinity) were within the acceptance range (0.80-1.25), satisfying the bioequivalence criteria of the Thailand Food and Drug Administration Guidelines. These results indicate that Dozozin-2 is bioequivalent to Cardura and, thus, may be prescribed interchangeably.

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.

[Medication combined with local hyperthermia: a desirable therapy for chronic prostatitis pain symptoms]

OBJECTIVE

To compare the effect of the combined therapy of medication with local hyperthermia with that of the simple local hyperthermia therapy in the treatment of pain symptoms of chronic prostatitis (CP).

METHODS

Seventy-six CP patients aged 18-48 (mean 29.2 +/- 3.8) years, with the disease course of 3.5-180 (mean 8.0 +/- 1.2) months and NIH-CPSI pain score > or = 14, were equally randomized into a treatment group and a control. The former was treated by applying the CRS-2280E extraorgan short-wave capacitance field hyperthermia system to the prostate once an hour every other day for 7 times, combined with anal administration of 1 Qianliean suppository and oral doxazosin 4 mg before bedtime every night for 2 weeks, while the latter underwent simple local hyperthermia. All the patients were scored on NIH-CPSI and the therapeutic results were compared between the two groups.

RESULTS

The pre- and post-treatment NIH-CPSI scores were (23.9 +/- 3.8) and (5.2 +/- 3.1) (P < 0.01) in the treatment goup and (24.5 +/- 4.3) and (11.6 +/- 3.4) (P < 0.01) in the control; the pre- and post-treatment scores on NIH-CPSI pain symptoms were (16.5 +/- 1.9) and (3.1 +/- 2.2) (P < 0.01) in the former and (15.9 +/- 1.7) and (8.2 +/- 2.0) (P < 0.01) in the latter. The total score on NIH-CPSI and that on NIH-CPSI pain symptoms were both significantly higher in the treatment group than in the control (P < 0.01). Within the treatment group, the score on NIH-CPSI pain symptoms was even more significantly improved in patients with the first attacks than in those already treated by other means (P < 0.01). No adverse effects were observed in either of the groups.

CONCLUSION

Both the combined therapy of medication with local hyperthermia and simple local hyperthermia are effective, safe and tolerable in the treatment of CP pain symptoms, and the former is even more desirable, particularly for those with the first attacks of the symptoms.

[Clinical and neuroimmunoendocrine effects of doxasosine in treatment of benign hyperplasia of the prostate in elderly people]

Benign hyperplasia of prostate is a very important not only medical but also social problem. The clinical and neuroimmunoendocrine status of elderly patients with benign hyperplasia of prostate treated by 1-blocker doxasosine is described in this article. Intercellular interactions were examined for tumor necrosis factor a (TNF-alpha), proinflammative interleukine-6 (IL-6), soluble intercellular molecule of adhesion (sICAM). The positive role of doxasosine is demonstrated.

[Changes in microcirculation of the urinary bladder in patients with stage II prostatic adenoma depending on the treatment method]

To determine microcirculation in the wall of the urinary bladder in prostatic adenoma, we used a laser analyzer of capillary circulation LAKK-01. Two groups participated in the trial: 105 males with stage II prostatic adenoma (the study group) and 25 volunteers (the control group). We estimated normal parameters of microcirculation in the wall of the bladder. In stage II prostatic adenoma the above microcirculation decreased to a subcritical perfusion level. Significantly earlier and complete recovery of microcirculation was observed in patients who had taken cardura (Pfizer) in a dose 2 mg/day for 3 months after transurethral resection of prostatic gland. Thus, 2 mg/day cardura (Pfizer) in patients with prostatic adenoma of stage II after TUR of the prostate promotes early and effective recovery of microcirculation.

[Clinical and neuroimmunoendocrine effects of doxasosine in treatment of arterial hypertension accompanied by prostate benign hyperplasia in elderly people]

Arterial hypertension accompanied by prostate benign hyperplasia is very important not medical but social problem in elderly people. The clinical and neuroimmunoendocrine status of elderly patients with arterial hypertension accompanied by prostate benign hyperplasia treated by alpha1-blocker doxasosine is described in the article. Intercellular interactions were examined for tumor necrosis factor alpha, proinflammative interleukine-6, soluble intersellular molecule of adhesion. The positive role of doxasosine is demonstrated.

The Effect of Doxazosin, Finasteride and Combination Therapy on Nocturia in Men With Benign Prostatic Hyperplasia

PURPOSE

We evaluated the effectiveness of single or combination drug therapy on nocturia in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

MATERIALS AND METHODS

A total of 3,047 men with lower urinary tract symptoms/benign prostatic hyperplasia enrolled in the Medical Therapy of Prostatic Symptoms trial were randomly assigned to receive doxazosin alone, finasteride alone, combination therapy or placebo. Treatment effectiveness was assessed according to intent to treat by mean reduction in self-reported nightly nocturia at 1 and 4 years. A subgroup analysis by age (younger than 70 vs 70 years old or older) was also performed.

RESULTS

Of the men 2,583 reported 1 or more episodes of nocturia and finished 12 or more months of the trial. Mean nocturia was similar in all groups at baseline. Mean nocturia was reduced at 1 year by 0.35, 0.40, 0.54 and 0.58 in the placebo, finasteride, doxazosin and combination groups, respectively. Reductions with doxazosin and combination therapy were statistically greater than with placebo (p <0.05). At 4 years nocturia was also significantly reduced in patients treated with doxazosin and combination therapy (p <0.05 vs placebo). In men older than 70 years (495) all drugs significantly reduced nocturia at 1 year (finasteride 0.29, doxazosin 0.46 and combination 0.42) compared to placebo (0.11, p <0.05).

CONCLUSIONS

Doxazosin and combination therapy reduced nocturia more than placebo, but the net benefit of active drug compared to placebo was often modest with a net difference of less than 0.20 fewer nightly nocturia episodes at 1 and 4 years. Findings in men 70 years old or older were similar, with an even smaller effect observed for finasteride.

[Case of baroreflex failure after bilateral revascularization of the cervical carotid artery]

We report a patient of baroreflex failure two years after bilateral cervical internal carotid artery (ICA) revascularization. A 76-year-old hypertensive man was admitted to our hospital after suffering multiple syncopal events for the past 2 years prior to admission. He received bilateral surgical and endovascular revascularization for stenotic lesions of the ICA orifices 4 years ago. Intervention consisted of carotid endarterectomy and carotid stenting for the right and left ICAs, respectively. Head T2-weighted magnetic resonance images demonstrated multiple high intensity signals in the basal ganglia bilaterally. To investigate his autonomic function, head-up tilt test, 24-hour ambulatory blood pressure measurements, and Valsalva's maneuver were performed. The patient demonstrated marked orthostatic hypotension without increment of heart rate, increased variability of blood pressure and abnormal hypertensive surges in a single 24 hour period, and abnormal response of heart rate during Valsalva's maneuver. These findings were indicative of impaired baroreflex-mediated vasomotor and heart rate control. Other examinations involving hematological analysis, cardiac function assessment, and scintigraphy for pheochromocytoma were within normal limits except for a marked increase in plasma norepinephrine during hypertensive surge. We therefore considered that he had baroreflex failure resulting from previous bilateral ICA orifice revascularization. The patient was given diazepam during hospitalization. After then, his blood pressure stabilized somewhat and syncopal attacks were controlled. Our case suggests that patients, who undergo bilateral ICA orifice revascularization and present with syncopal attacks, should be considered baroreflex failure even if the patient is post-operative several years. Long-term follow up should therefore be necessitated in patients who undergo bilateral carotid revascularization.

[Benign prostatic hyperplasia: medical therapy]

Primary aims of the medical therapy for BPH are improvement of subjective symptoms and quality of life as well as the prevention of long-term complications such as acute urinary retention and renal failure. Secondary goal is inhibition of disease progression. The medical therapy should be tailored to each patient according to the individual complaints and risk of progression. Plant extracts, alpha-blockers and 5-alpha reductase inhibitors represent the most common prescribed substances. Recent data suggest beneficial effects for the use of antimuscarinic agents and phosphodiesterase type 5 inhibitors.

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.

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?

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.

Doxazosin for the Management of Distal-Ureteral Stones

PURPOSE

To evaluate the efficacy of doxazosin in inducing spontaneous passage of stones in the distal ureter and to compare its efficacy according to the size of the stone.

PATIENTS AND METHODS

Seventy-three patients with a mean age of 46.38 +/- 10.17 years who presented with a distal-ureteral stone were divided into four groups according to stone size and drug treatment: <5 mm without doxazosin (group A; n=15); 5-10 mm (group B; n=16); <5 mm with doxazosin 4 mg/day for 4 weeks (group C; n=20); and 5-10 mm with doxazosin 4 mg/day for 4 weeks (group D; n=22). Groups A and B served as controls for groups C and D, respectively.

RESULTS

Spontaneous stone passage was documented in 9 patients (60%) in group A v 17 (85%) in group C (P=0.047) and 7 (43.75%) in group B v 16 (72.73%) in group D (P=0.036). The average expulsion time was 8.78 +/- 1.09 days in group A v 7.59 +/- 0.80 days in group C (P=0.004) and 12.14 +/- 1.35 days in group B v 7.06 +/- 1.29 days in group D (P<0.0001). The number of pain episodes in group D patients was significantly lower than in group B (P +/- 0.0078).

CONCLUSIONS

Doxazosin treatment proved to be safe and effective for distal-ureteral stones, as determined by earlier expulsion, decreased colic frequency, and absence of side effects. The efficacy of doxazosin was significantly higher for 5-to 10-mm stones than for smaller ones.

[Perioperative treatment of a patient with ectopic ACTH-producing pheochromocytoma]

This report deals with perioperative treatment for a very rare disease called ectopic ACTH-producing pheochromocytoma in a 55-year-old woman. She showed high norepinephrine, cortisol, and ACTH levels, and diagnosed as ectopic ACTH-producing pheochromocytoma, by MIBG scintigraphy. An alpha-blocker and fluid loading for pheochromocytoma, and an adrenal cortex hormone synthesis inhibitor for Cushing's syndrome, were given simultaneously as a preoperative treatment. Propofol with nitrous oxide-oxygen-sevoflurane and epidural anesthesia were used for excision of the tumor, and the procedure was performed without any marked changes in hemodynamics. Although ectopic ACTH-producing pheochromocytoma is a very rare disease, it can be managed safely by appropriate preoperative treatment for pheochromocytoma and Cushing's syndrome.

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.

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.

The effect of carvedilol on metabolic parameters in patients with metabolic syndrome

The objective of the present study was to explore the effect of carvedilol treatment on metabolic parameters in patients with metabolic syndrome. A total of 77 patients > or = 20 years of age (59 females, 18 males, mean age, 52.3 +/- 10.3) with stage 1 hypertension who fulfilled at least 3 of the metabolic syndrome criteria proposed by NCEP-ATP III were included in this prospective, randomized, controlled study. Patients were randomly assigned to receive daily treatment with carvedilol (n = 27, 12.5 mg/day orally for the first 2 days and 25 mg/day thereafter), atenolol (n = 26, 50 mg/day orally), or doxazosin (n = 24, 2 mg/day orally) for 90 days. Doses were doubled at the end of the 3rd week in patients whose blood pressure was inadequately controlled and amlodipine 10 mg was added to the treatment if the target blood pressure was still not reached at the end of week 6. The biochemical parameters and insulin sensitivity based on the HOMA-IR model were evaluated at baseline and at the end of treatment. Similar reductions in systolic and diastolic blood pressure were observed in all groups (P > 0.05). A significant decrease in HDL cholesterol levels occurred in the doxazosin and atenolol groups compared to the carvedilol group (percent change: -5.6 +/- 13.5 and -8 +/- 9.8 versus -0.1 +/- 12.2, respectively; P < 0.05) and a significant increase in apolipoprotein A1 level was observed in the carvedilol group compared to the doxazosin and atenolol groups (percent change: + 4.3 +/- 9.6 versus - 0.5 +/- 10.6 and -2.3 +/- 6.6, respectively; P < 0.05). There were no significant differences among the groups with respect to other parameters. It is concluded antihypertensive treatment with carvedilol in patients with metabolic syndrome effectively reduces blood pressure without adversely affecting metabolic parameters.

Chiral selective effects of doxazosin enantiomers on blood pressure and urinary bladder pressure in anesthetized rats

AIM

To study chiral selective effects of doxazosin enantiomers on blood pressure and urinary bladder pressure in anesthetized rats.

METHODS

In anesthetized rats, the carotid blood pressure, left ventricular pressure of the heart and the urinary bladder pressure were recorded.

RESULTS

Administration of S-doxazosin at 0.25, 2.5, 25, and 250 nmol/kg iv produced a dose-dependent decrease in blood pressure, but its depressor effect was significantly weaker than that induced by R-doxazosin and racemic-doxazosin (rac-doxazosin), and the ED(30) values (producing a 30% decrease in mean arterial pressure) of R-doxazosin, rac-doxazosin and S-doxazosin were 15.64, 45.93, and 128.81, respectively. Rac-doxazosin and its enantiomers administered cumulatively in anesthetized rats induced a dose-dependent decrease in the left ventricular systolic pressure and +/-dp/dt(max), and the potency order of the 3 agents was R-doxazosin > rac-doxazosin > S-doxazosin. Rac-doxazosin and its enantiomers decreased the vesical micturition pressure dose-dependently at 2.5, 25, and 250 nmol/kg, and the inhibitory potency among the 3 agents was not significantly different.

CONCLUSION

S-doxazosin decreases the carotid blood pressure and left ventricular pressure of the heart less than R-doxazosin and rac-doxazosin, but its effect on the vesical micturition pressure is similar to R-doxazosin and rac-doxazosin, indicating that S-doxazosin has chiral selectivity between cardiovascular system and urinary system in anesthetized rats.