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

Lipid Horizons: Recent Advances and Future Prospects in LBDDS for Oral Administration of Antihypertensive Agents

The lipid-based drug delivery system (LBDDS) is a well-established technique that is anticipated to bring about comprehensive transformations in the pharmaceutical field, impacting the management and administration of drugs, as well as treatment and diagnosis. Various LBDDSs verified to be an efficacious mechanism for monitoring hypertension systems are SEDDS (self-nano emulsifying drug delivery), nanoemulsion, microemulsions, vesicular systems (transferosomes and liposomes), and solid lipid nanoparticles. LBDDSs overcome the shortcomings that are associated with antihypertensive agents because around fifty percent of the antihypertensive agents experience a few drawbacks including short half-life because of hepatic first-pass metabolism, poor aqueous solubility, low permeation rate, and undesirable side effects. This review emphasizes antihypertensive agents that were encapsulated into the lipid carrier to improve their poor oral bioavailability. Incorporating cutting-edge technologies such as nanotechnology and targeted drug delivery, LBDDS holds promise in addressing the multifactorial nature of hypertension. By fine-tuning drug release profiles and enhancing drug uptake at specific sites, LBDDS can potentially target renin-angiotensin-aldosterone system components, sympathetic nervous system pathways, and endothelial dysfunction, all of which play crucial roles in hypertension pathophysiology. The future of hypertension management using LBDDS is promising, with ongoing reviews focusing on precision medicine approaches, improved biocompatibility, and reduced toxicity. As we delve deeper into understanding the intricate mechanisms underlying hypertension, LBDDS offers a pathway to develop next-generation antihypertensive therapies that are safer, more effective, and tailored to individual patient needs.

Silodosin as a predisposing factor of intraoperative floppy iris syndrome (IFIS): an observational propensity score-matching cohort study

PURPOSE

To evaluate the correlation between silodosin and intraoperative floppy iris syndrome (IFIS) and compare it with other a1-adrenergic receptor antagonists (a1-ARAs) and other factors predisposing to IFIS.

METHODS

From the patients who underwent phacoemulsification between 2014 and 2020, we identified all patients who, during their preoperative assessment, reported an a1-ARAs intake (exposed group). These patients were matched utilizing a propensity score matching analysis with an otherwise homogenous group of patients (control group) based on demographics and systemic/ocular comorbidities.

RESULTS

A total of 350 patients were included in each group. In the exposed group, 177 (50.6%) patients were exposed to tamsulosin, 105 (30%) to alfuzosin, 43 (12.2%) to silodosin. Regarding IFIS, it was observed in 21.5% of patients on tamsulosin (38/177), 11.4% on alfuzosin (12/105), 37.2% on silodosin (16/43), and 3.4% in the controlled group (12/350). In a multiple regression model analysis, the only two factors significantly associated with IFIS development were silodosin and tamsulosin yielding an adjusted odds ratio of 8.471 (95%CI 4.005-17.920) and 3.803 (95%CI 2.231-6.485), respectively.

CONCLUSION

Silodosin has been demonstrated as a predisposing factor, strongly correlated with IFIS development. These results should increase cataract surgeons' awareness to assess their patients preoperatively for exposure to silodosin carefully and employ the appropriate prophylactic measures to ameliorate the impact of silodosin intake on the surgical outcome.

Doxazosin Attenuates Liver Fibrosis by Inhibiting Autophagy in Hepatic Stellate Cells via Activation of the PI3K/Akt/mTOR Signaling Pathway

Purpose

To investigate the effect of doxazosin on autophagy and the activation of hepatic stellate cells (HSCs) in vivo and in vitro and determine the underlying mechanism.

Methods

In vivo, a mouse liver fibrosis model was induced by the intraperitoneal injection of carbon tetrachloride (CCl₄). Doxazosin was administered at doses of 2.5, 5 and 10 mg/(kg*day) by gavage. After 20 weeks, blood and liver tissues were collected for serological and histological analysis, respectively. Blood analysis, hematoxylin and eosin (HE) staining, Masson’s trichrome staining, immunohistochemistry and immunofluorescence staining were used to measure the extent of liver fibrosis in model and control mice. In vitro, the human HSC cell line LX-2 was cultured and treated with different doses of doxazosin for the indicated times. The effects of doxazosin on LX-2 cell proliferation and migration were examined by Cell Counting Kit-8 (CCK-8) and Transwell assays, respectively. The number of autophagosomes in LX-2 cells was observed by transmission electron microscopy (TEM). Infection with green fluorescent protein (GFP)-LC3B adenovirus, GFP-red fluorescent protein (RFP)-LC3B adenovirus and mCherry-EGFP-LC3 adeno-associated virus was performed to examine changes in autophagic flux in vitro and in vivo. Cell apoptosis was measured by flow cytometry in vitro and by TUNEL assays both in vitro and in vivo. Immunoblotting was performed to evaluate the expression levels of proteins related to fibrosis, autophagy, apoptosis, and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR).

Results

Doxazosin inhibited HSC proliferation and migration. HSC activation was attenuated by doxazosin in a concentration-dependent manner in vivo and in vitro. Doxazosin also blocked autophagic flux and induced apoptosis in HSCs. In addition, the PI3K/Akt/mTOR pathway was activated by doxazosin and regulated fibrosis, autophagy and apoptosis in HSCs.

Conclusion

The study confirmed that doxazosin could inhibit autophagy by activating the PI3K/Akt/mTOR signaling pathway and attenuate liver fibrosis.

Statins are effective in the treatment of benign prostatic hyperplasia with metabolic syndrome

OBJECTIVE

To compare the efficacy of statins and ɑ blockers drug therapies for benign prostatic hyperplasia (BPH) in patients with metabolic syndrome (MetS).

MATERIALS AND METHOD

A total of three hundred patients were randomly distributed into three groups of one hundred patients each. Group 1 received only ɑ-adrenoceptor antagonist (ɑ-blocker, AB) (Tamsulosin), group 2 received only statin (atorvastatin), and group 3 received AB plus statin (Tamsulosin + Atorvastatin). The efficacy measurement was assessed by analyzing the changes from baseline in the total International Prostate Symptom Score (IPSS), disease-specific QoL question score and maximum urinary flow rate at the end of 6 months in each group and between the three groups.

RESULTS

Pre-treatment and post-treatment value of triglycerides (TG), high-density lipoprotein (HDL), and prostate volüme (PV) were not significantly different in AB group, while TG and PV were significantly lower in patients taking statin and combined therapy. The significant decrease was demonstrated in maximum urinary flow rate (Q_max) in three groups. However, the most significant decrease was observed in the combination therapy group. IPSS, postvoid residual urine volüme (PVR), and Quality of Life score (QoL) significantly changed in three groups.

CONCLUSION

We recommend of the use of statins in those men with BPH accompanied by MetS in which AB is ineffective alone.

Intraoperative Floppy Iris Syndrome: Updated Perspectives

Almost fifteen years since its initial description, intraoperative floppy iris syndrome (IFIS) during phacoemulsification surgery remains a challenge for cataract surgeons in all its key aspects that include the stratification of the preoperative risk, preoperative prophylaxis treatment, surgery design and intraoperative management. Since its original association with tamsulosin intake, IFIS has been positively correlated with a plethora of risk factors which include: gender, age, hypertension, other a1-adrenergic receptor antagonists, finasteride, angiotensin II receptor inhibitors, benzodiazepines, antipsychotics, hypertension drugs and decreased dilated pupil diameter. The assessment and stratification of the preoperative risk is pivotal in screening patients prone to develop IFIS. For these patients, it is essential that preoperative prophylaxis, employment of necessary measures and surgical technique modifications are considered. A multidisciplinary approach of IFIS is a mandate, thus ophthalmologists, urologists and sometimes other specialties should cooperate to “educate” each other about the risks of their respective fields. They both must be aware of the joint statement on IFIS by the American Academy of Ophthalmology and the American Society of Cataract and Refractive Surgery which suggests either the initiation of tamsulosin after phacoemulsification or the use of a non-selective a1-ARA for benign prostatic hyperplasia treatment. In conclusion, awareness of the risk factors associated with IFIS and their detailed preoperative documentation is crucial in addressing IFIS. The lack of such an awareness can turn a routine, uneventful surgery into one with significant visual morbidity.

Doxazosin down-regulates sodium-glucose cotransporter-2 and exerts a renoprotective effect in rat models of acute renal injury

Sodium-glucose cotransporter-2 (SGLT2) is known to be involved in the progression of acute renal injury (ARI) and is regulated by different mediators in the kidneys including extracellular signal-regulated kinase (ERK), hypoxia-inducible factor 1 alpha (HIF1α) and prostaglandin E2 (PGE2). In the present study, we investigated the possible protective effect of doxazosin on renal ischaemia/reperfusion (IR) and glycerol-induced ARI by determining its effect on SGLT2 via modifying ERK-HIF1α pathway and/or PGE2. Rats were divided into control, sham or IR where the rats received the vehicle, doxazosin (8 mg/kg) or the SGLT2 inhibitor, dapagliflozin (10 mg/kg) for 3 days followed by 45 minutes bilateral renal ischaemia then 24 hours reperfusion. Another group of rats received the vehicle, doxazosin or dapagliflozin for three days followed by injection of 50% glycerol (8 mL/kg, IM) or saline. Kidney function tests, systolic blood pressure (SBP), oxidative stress markers (malondialdehyde [MDA] and NADPH oxidase), nitric oxide (NO), inducible nitric oxide synthase (iNOS), HIF1α, ERK phosphorylation and PGE2 levels were determined. Additionally, renal sections were used for immunological expression of SGLT2. ARI rats showed significantly increased SBP; worsened kidney function tests; increased oxidative stress, iNOS, NO, HIF1α levels; and decreased PGE2 and ERK phosphorylation along with up-regulated SGLT2. Doxazosin treatment protected against the kidney damage and attenuated the associated biochemical changes. Doxazosin has a direct renoprotective effect possibly by down-regulating SGLT2.

Biodegradable synthetic polyesters in the technology of controlled dosage forms of antihypertensive drugs - the overview

Introduction: Arterial hypertension is a disease of civilization that requires long-term treatment. Recently, growing interest in natural and synthetic polymers as drug delivery vehicles in controlled release dosage forms for improving the efficacy of treatment has been observed. Areas covered: This review introduces biodegradable synthetic polyesters as macromolecular carriers of antihypertensive drugs. Although various, synthetic and natural polymer-drug conjugates and/or polymeric carriers of anticancer drugs are currently under preclinical and clinical studies, there is no such data for antihypertensive drugs. Therefore, it seems appropriate to use such materials for the treatment of hypertension. Expert opinion: There are currently only a few studies describing the use of synthetic polyesters in the arterial hypertension therapy. In order to the fact that there is a high demand for new, effective antihypertensive dosage forms, further studies for such drug carriers are certainly expected. Synthetic polyester carriers could improve the drug bioavailability and its pharmacokinetic properties by altering the pharmaceutical dosage form. This property is particularly useful for drugs with proven pharmacological action, but with limited application due to their inappropriate pharmacological properties. The development of new polymeric materials and technologies affords the opportunity to produce novel synthetic polyester DDSs.

Doxazosin for the treatment of co-occurring PTSD and alcohol use disorder: Design and methodology of a randomized controlled trial in military veterans

Posttraumatic stress disorder (PTSD) and alcohol use disorders (AUD) are two of the most common mental health disorders affecting civilians as well as military populations. If left untreated, individuals with co-occurring PTSD/AUD are at increased risk for developing other mental health problems (e.g., depression, anxiety), physical health problems, reduced resiliency and military readiness, and vocational and social impairment. Substantial gaps in the treatment of co-occurring PTSD/AUD exist and there is a critical need to develop more effective pharmacological treatments. The current study addresses this gap in the literature by testing the efficacy and safety of doxazosin, a long-acting and selective alpha-1 adrenergic antagonist, as compared to placebo in reducing PTSD and AUD severity among U.S. military veterans. Noradrenergic dysregulation has been implicated in the development and maintenance of PTSD and AUD, and pilot studies examining doxazosin in PTSD-only or AUD-only samples have shown promise. This is the first study, however, to evaluate doxazosin in a comorbid PTSD/AUD sample. This paper describes the rationale, design and methodology of a randomized, double-blind, placebo-controlled trial of doxazosin (16 mg/day) delivered over 12 weeks among military veterans with current PTSD and AUD. In addition, functional magnetic resonance imaging (fMRI) is applied at pre- and post-treatment to investigate the underlying pathophysiology of comorbid PTSD/AUD and identify prognostic indicators of treatment outcome. This study is designed to accelerate research on co-occurring PTSD/AUD and provide empirical evidence to inform clinical practice.

A Randomized, Open-Label, Comparative Study of Efficacy and Safety of Tolterodine Combined with Tamsulosin or Doxazosin in Patients with Benign Prostatic Hyperplasia

Background

Benign prostatic hyperplasia (BPH), a common disease in men over age 50 years, often causes bladder outlet obstruction and lower urinary tract symptoms (LUTS). Alpha blockers in combination with muscarinic receptor antagonists may have the potential to improve symptoms. This study aimed to assess the efficacy and safety of doxazosin or tamsulosin combined with tolterodine extend release (ER) in patients with BPH and LUTS.

Material/Methods

In a prospective, randomized, open-label study (ChiCTR-IPR-15005763), 220 consecutive men with BPH and LUTS were allocated to receive doxazosin 4 mg and tolterodine ER 4 mg per day (doxazosin group) or tamsulosin 0.2 mg and tolterodine ER 4 mg per day (tamsulosin group). Treatment lasted 12 weeks. The primary endpoint was the international prostatic symptom score (IPSS). Secondary endpoints were quality of life (QoL) and maximum flow rate (Q_max), which were evaluated at 0, 6, and 12 weeks, and urodynamic parameters assessed at 0 and 12 weeks.

Results

A total of 192 patients completed the trial. Baseline measurements showed no differences between the groups. After 6 weeks, IPSS improved in both groups and QoL was significantly better in the doxazosin group (P=0.01). After 12 weeks, Q_max, IPSS, QoL, intravesical pressure (Pves), and bladder compliance (BC) in the doxazosin group were significantly better than in the tamsulosin group (P=0.03, P<0.001, P<0.001, P=0.027, and P=0.044, respectively).

Conclusions

Administration of alpha blockers combined with muscarinic receptor blocker for 12 weeks improved LUTS in men with BPH.

Croton membranaceus Improves Some Biomarkers of Cardiovascular Disease and Diabetes in Genetic Animal Models

INTRODUCTION

Cardiovascular disease (CVD) accounts for 17.3 million deaths per year globally. In Ghana, CVD accounts for 22.2% of deaths. Croton membranaceus (CM) Mull. Arg. (Euphorbiaceae), a medicinal plant in Ghana is mainly used traditionally for the treatment of benign prostatic hyperplasia and measles. However, some hypoglycaemic and hypotensive effects have recently been reported but not scientifically examined.

AIM

The study aimed at establishing whether Croton membranaceus (CM) used for prostatitis had any effect on CVD markers.

MATERIALS AND METHODS

In experiment 1, lipid profile changes were determined. Twenty four male Spontaneously Hypertensive Rats (SHR) were divided into 4 groups. Low (LD), intermediate (ID) and high dose (HD) groups received 25, 50 and 100 mg/kg b.wt. CM aqueous root extracts (CMARE) for 60 days, respectively, the controls received distilled water. In experiment 2, blood glucose levels (BGL) were determined. 21 db/db mice were divided into 3 groups of 7 mice each alongside db/+ mice (7) (negative control). Groups 1 and 2 received 250 mg/kg b.wt CMARE and metformin, respectively. Group 3 (positive control) and db/+ mice (negative control) received distilled water. Mice were monitored for 15 hours. Data collected were analysed using SPSS version 20.

RESULTS

Hypotriglyceridaemic effect was observed (p=0.005). High Density Lipoprotein cholesterol (HDL) and Low Density Lipoprotein cholesterol (LDL) showed significant increases (p=0.013) and decreases (p=0.003), respectively. A significant CRP reduction was observed for ID and HD groups (p = 0.010, p = 0.011, respectively). BGL was reduced in Metformin and Croton groups (p=0.000; p= 0.006, respectively) after 3 hours.

CONCLUSION

In conclusion, CMARE has positive effects on some CVD biomarkers and a hypoglycaemic effect.

Enantioselective pharmacokinetics of doxazosin and pharmacokinetic interaction between the isomers in rats

In this study, the stereoselective pharmacokinetics of doxazosin enantiomers and their pharmacokinetic interaction were studied in rats. Enantiomer concentrations in plasma were measured using chiral high-pressure liquid chromatography (HPLC) with fluorescence detection after oral or intravenous administration of (-)-(R)-doxazosin 3.0 mg/kg, (+)-(S)-doxazosin 3.0 mg/kg, and rac-doxazosin 6.0 mg/kg. AUC values of (+)-(S)-doxazosin were always larger than those of (-)-(R)-doxazosin, regardless of oral or intravenous administration. The maximum plasma concentration (Cmax ) value of (-)-(R)-doxazosin after oral administration was significantly higher when given alone (110.5 ± 46.4 ng/mL) versus in racemate (53.2 ± 19.7 ng/mL), whereas the Cmax value of (+)-(S)-doxazosin did not change significantly. The area under the curve (AUC) and Cmax values for (+)-(S)-doxazosin after intravenous administration were significantly lower, and its Cl value significantly higher, when given alone versus in racemate. We speculate that (-)-(R)-doxazosin increases (+)-(S)-doxazosin exposure probably by inhibiting the elimination of (+)-(S)-doxazosin, and the enantiomers may be competitively absorbed from the gastrointestinal tract. In conclusion, doxazosin pharmacokinetics are substantially stereospecific and enantiomer-enantiomer interaction occurs after rac-administration.

Doxazosin in the treatment of scorpion envenomation

OBJECTIVE

To investigate effectiveness and applicability of Doxazosin in the treatment of scorpion stings in patients who had systemic symptoms.

METHODS

The medical records of patients were retrospectively reviewed, and the following data were collected: age, sex, clinical symptoms (localized and systemic), vital signs, information on the date and place of the sting occurrence, the anatomical sting site, time between sting and arrival to the hospital, scorpion identification, severity of the symptoms and treatment.

RESULTS

Of the victims, 48.5 % (n = 16) were males, and 51.5 % (n = 17) were females, with a mean age of 6.8 ± 4.2 y. The most common sting site was lower extremity 72.7 % (n = 24). Systemic toxicity (class II) was seen in 93.9 %, and two patients (6.1 %) manifested evidence of severe envenomation (class III). Both local and systemic effects were seen in the patients. Cold extremities persisted for 4.5 ± 1.5 h after administration of Doxazosin. Mean hospitalization time was 2.5 ± 1.5 d (range: 1.5 to 6 d). Thirty-two patients recovered without any sequel, whereas one patient died due to cardio-pulmonary insufficiency.

CONCLUSIONS

Doxazosin, especially if Prazosin is not available, can be recommended as an effective drug in the treatment of serious scorpion envenomations with significant sympathetic symptoms.

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.

The role of alpha blockers prior to removal of urethral catheter for acute urinary retention in men

BACKGROUND

Acute urinary retention is a urological emergency in men and requires urgent catheterisation. Any intervention which aims at improving urinary symptoms following an acute urinary retention episode could be potentially beneficial. Alpha blockers relax prostatic smooth muscle cells thereby decreasing the resistance to urinary flow and by doing so could improve urinary symptoms.

OBJECTIVES

To assess the effectiveness of alpha blockers on successful resumption of micturition following removal of a urethral urinary catheter after an episode of acute urinary retention in men. In the absence of internationally agreed outcome measures for the success of a trial without catheter, success was defined as the return to satisfactory voiding without need for re-catheterisation within 24 hours.

SEARCH METHODS

We searched the Cochrane Incontinence Group Specialised Trials Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE in process, and handsearching of journals and conference proceedings (searched 9 October 2013), CENTRAL (2013, Issue 5) (searched 5 June 2013), MEDLINE 1946 to May Week 4 2013, MEDLINE in Process (covering to 3 June 2013), EMBASE Classic and EMBASE 1947 to 2013 Week 22 (all searched 4 June 2013) and the reference lists of relevant articles. No language or other restrictions were imposed on the searches.

SELECTION CRITERIA

Only randomised and quasi-randomised clinical trials of alpha blockers for trial without a urethral catheter following an episode of acute urinary retention in men were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently examined all the citations and abstracts derived from the search strategy. Any disagreement about trial selection and inclusion was resolved by discussion. A third independent judgement was sought where disagreement persisted. Two review authors extracted independently, cross-checked and processed the data as described in the Cochrane Handbook for Systematic Reviews of Intervention. Quality of evidence of the critical outcomes was assessed by adopting the GRADE approach.

MAIN RESULTS

Nine randomised clinical trials were included in this review. Eight trials compared alpha blockers versus placebo (five trials tested alfuzosin and two trials tested tamsulosin, one trial tested both alfuzosin and tamsulosin, one trial tested silodosin) and one trial compared an alpha blocker (doxazosin) versus no treatment. Trial without catheter was performed after treatment with the drug for one to three days in seven trials and for eight and 32 days in two other trials respectively. There was moderate quality evidence to suggest that the rate of successful trial without catheter favoured alpha blockers over placebo ( 366/608, 60.2%, of men using an alpha blocker were able to void spontaneously after catheter removal compared with 185/486, 38.1%, using placebo, risk ratio (RR) 1.55, 95% confidence interval (CI) 1.36 to 1.76). The incidence of recurrent acute urinary retention was lower in groups treated with an alpha blocker (RR 0.69, 95% CI 0.60 to 0.79). This evidence was of moderate quality and was statistically significant for alfuzosin, tamsulosin and silodosin, though not for doxazosin. Of the trials mentioning adverse effects (for example, postural hypotension, dizziness), there was not enough information to detect statistically significant differences between the groups (RR 1.19, 95% CI 0.75 to 1.89) and the evidence was of low quality. Overall, adverse effect rates were low for both placebo and alpha blockers and, for example, vasodilatation-related adverse effects did not often result in discontinuation.

AUTHORS' CONCLUSIONS

There was some evidence to suggest that alpha blockers increase the success rates of trial without catheter, and the incidence of adverse effects was low. There was some evidence of a decreased incidence of acute urinary retention. The need for further surgery, cost effectiveness and recommended duration of alpha blocker treatment after successful trial without catheter remain unknown as these were not reported by any trial. There is a lack of internationally agreed outcome measures for what constitutes successful trial without catheter. This makes meta-analysis difficult. Large, well-designed controlled trials, which use the recommendations set out in the CONSORT statement, and include clinically important outcome measures, are required.

Doxazosin selectively potentiates contraction to serotonin via 5-HT₂A receptors in longitudinal muscle strips of the rabbit gastric body

The aims of this study were to examine the effects of doxazosin on contractile responses to 5-hydroxytryptamine (5-HT), carbachol, and histamine, and to compare them with those of prazosin, alfuzosin, and terazosin, and then characterize a pharmacological profile of the 5-HT-induced contractile response using preparations of isolated longitudinal muscle strips from the rabbit gastric body. The results from these preparations showed that the contraction response to 5-HT, but not to carbachol or histamine, was found to be dose-dependently potentiated by doxazosin and its enantiomers. The specific potentiation effect on 5-HT was not observed in the preparations that were treated with prazosin, terazosin, or alfuzosin. The contractile response to 5-HT and its potentiation by doxazosin were not affected by treatment with phenoxybenzamine. However, 5-HT-induced contraction was competitively antagonized by nefazodone (with pA₂ value of 8.64 ± 0.17), and was almost completely inhibited by treatment with indomethacin. In conclusion, doxazosin, but not prazosin, alfuzosin, or terazosin, selectively potentiates 5-HT-induced contraction in the rabbit gastric body strips via an α₁-adrenoceptor-independent mechanism, without chiral recognition of its enantiomers. Additionally, the contraction to 5-HT was found to be mediated via 5-HT(₂) receptors, and was similar to PGs synthesis in the preparations.

Effects of Doxazosin on Alpha 1-Adrenergic Receptors in Prostates with Benign Prostatic Hyperplasia

OBJECTIVES

The present study aimed to evaluate changes in mRNA and protein expression levels of α1-AR before and after doxazosin treatment.

METHODS

This 12-month, prospective study included males aged 50 or older who had lower urinary tract symptoms (LUTS) (International Prostate Symptom Score [IPSS] ≥ 8) with benign prostatic hyperplasia (BPH). All patients underwent transrectal ultrasound-guided prostate biopsy before and after doxazosin 4 mg medication for 12 months. The mRNA and protein expression of prostate α1-AR were analyzed using real-time quantitative reverse transcription-polymerase chain and Western blotting, respectively, before and after treatment. The clinical efficacy of doxazosin was evaluated according to changes in prostate volume, serum prostate-specific antigen (PSA) level, IPSS, quality of life (QoL) index, maximum flow rate, parameters in a voiding diary, and a Patient's Perception of Bladder Condition (PPBC) questionnaire.

RESULTS

Twenty patients aged 50-72 (median age 66) with LUTS secondary to BPH completed this study. Administering doxazosin for 12 months significantly increased α1-AR protein expression in the prostate. α1-AR mRNA expression did not change significantly after doxazosin administration. IPSS, QoL index, and PPBC scores significantly improved after 12 months of doxazosin treatment. Maximal flow rate, postvoid residual urine volume (PVR), prostate volume and the parameters from the voiding diary did not change significantly after 12 months. The change of IPSS total score and LUTS were maintained until 12 months after starting treatment with doxazosin.

CONCLUSION

Doxazosin treatment was able to increase α1-AR protein expression in the prostate. Despite increased α1-AR expression, doxazosin provides sustained, significant relief of LUTS for up to one year without a decrease in efficacy.

The impact of metabolic syndrome on the responsiveness to α1-blocker in men with BPH/LUTS

AIMS

Increasing evidence has proposed the components of metabolic syndrome (MtS) as risk factors for the development of benign prostate hyperplasia (BPH); therefore, it is thought that MtS may play a role in lower urinary tract symptoms related to BPH (BPH/LUTS) aetiology. Considering the closed relationships between MtS and BPH/LUTS, it is possible that patients with MtS might have different drug responsiveness in men with BPH/LUTS. We prospectively investigated the impact of MtS on responsiveness to α1-blocker in men with BPH/LUTS.

METHODS

We enrolled a total of 109 patients with a mean (SD) age of 59.8 (9.0) years, having a prostate volume of 20 cm(3) or greater with moderate to severe LUTS. All patients received doxazosin GITS (gastrointestinal therapeutic system) 4 mg once daily for a 12-week period of treatment. The efficacy measurement was assessed by the changes from baseline in the total IPSS, maximum urinary flow rate and postvoid residual urine volume. The drug responders were defined as those who had a total IPSS decrease of more than 4 points from baseline after 12 weeks of treatment.

RESULTS

Using multiple logistic regression analysis, our results showed that MtS was an independent factor for drug non-responder (OR = 4.26, p = 0.002). The rate of drug responder and total IPSS improvements in patients with MtS significantly decreased as the number of MtS components increased (p = 0.012 and p = 0.026). Among the MtS components, abnormal fasting blood glucose (FBG) was the most significantly independent factor for drug non-responder (OR = 3.17, p = 0.020).

CONCLUSION

This study suggested that the presence of MtS had a significantly negative impact on the responsiveness to α1-blocker in men with BPH/LUTS. Our results are important for BPH/LUTS patients who did not initially respond to α1-blocker or who strive to reduce these metabolic risk factors.

Preparation and evaluation of sustained-release doxazosin mesylate pellets

Doxazosin mesylate (DXM) sustained release pellets were prepared by an extrusion-spheronization and fluid-bed coating technique. The core pellets containing DXM were prepared by extrusion-spheronization technique, and coated by a fluid-bed coater to control the release of DXM. The factors affecting to properties of pellets, such as diluent content, type and coating level of coating agents and plasticizers were studied in the present study. Polymethacrylate derivatives (Eudragit® RS PO and RL PO) were used for coating agents, and polyethylene glycol 6000 (PEG 6000), triethyl citrate (TEC) and castor oil were as plasticizers. To evaluate the properties of prepared pellets, the size of prepared pellets was investigated by sieve analysis technique and the morphology of pellets was evaluated by scanning electron microscopy. Through the dissolution test, factors that have an effect on the dissolution of the drug were evaluated. As the content ratio of microcrystalline cellulose (MCC) had increased, the dissolution was proportionally sustained. Eudragit® RS PO had more marked sustaining effect on the dissolution rate than Eudragit® RL PO, and the effect was more pronounced with the increased coating level. PEG 6000 was an appropriate plasticizer for DXM pellets, and increasing the content of PEG 6000, was also slightly decreasing the dissolution rate.

Commentary: Doxazosin for alcoholism

Recent preclinical and clinical evidence using prazosin indicates that α(1) -blockade may represent a new approach to treat alcohol dependence (AD). While most of the alcohol research on α(1) -blockade has been conducted testing prazosin, O'Neil and colleagues recently performed a set of preclinical experiments testing another α(1) -blocker, doxazosin, which has a longer half-life that may enhance clinical utility. Doxazosin and prazosin share the same chemical structure, in which the central element is a piperazine ring. O'Neil and colleagues' main results are that doxazosin significantly reduced alcohol intake without affecting locomotor activity. As such, O'Neil and colleagues provide the first preclinical evidence of the possible role of doxazosin in AD. Additional translational research is needed to further test this hypothesis.

Advances in the design and synthesis of prazosin derivatives over the last ten years

INTRODUCTION

Mechanistic, translational and pharmacological studies led to the identification and discovery of the preferred localization, binding characteristics, structure and functional properties of α1-adrenoceptor (α1-AR) subtypes in the bladder neck, bladder and prostate gland. The evidence gathered on α1-ARs, provided a molecular platform for the development of subtype-selective antagonists, resulting in more effective approaches targeting those receptors for the treatment of outlet bladder obstruction and benign prostate hyperplasia.

AREAS COVERED

Advances over the last decade in the design and optimization of Prazosin, Doxazosin and Terazosin quinazoline-based derivatives as α1-AR antagonists. Evidence on the metabolic and growth interference action by these agents, in addition to their smooth-muscle-relaxing effects. The new action recognition emerges from data on the inhibitory effect of quinazoline-based antagonists on primary tumor growth and progression to metastasis. In addition to the cellular findings in the prostate, functional validation and therapeutic effects of selected lead pharmaceutically optimized derivatives in the context of impairing vascularity and triggering tumor apoptosis.

EXPERT OPINION

Knowledge on targeting intracellular signalling pathways driving the cellular response via an α1-AR-dependent and independent antagonistic action, must be invested towards the optimization of new agents that while bypassing AR, exhibit improved pharmacological efficacy against human cancer.

Comparative rapid onset of efficacy between doxazosin gastrointestinal therapeutic system and tamsulosin in patients with lower urinary tract symptoms from benign prostatic hyperplasia: a multicentre, prospective, randomised study

AIMS

To compare the rapidity of improvement in lower urinary tract symptoms (LUTS) for the doxazosin gastrointestinal therapeutic system (GITS) and tamsulosin in benign prostatic hyperplasia (BPH) patients.

METHODS

A total of 207 patients were randomised to one of two groups for a 12-week daily treatment with doxazosin-GITS 4 mg or tamsulosin 0.2 mg. The primary end-point was to compare the early onsets of efficacy between the two drugs. This was assessed by analysing the changes from baseline in the total International Prostate Symptom Score (IPSS) in the early period of treatment. Secondary aims were to compare improvements in obstructive/irritative subscore and quality of life (QoL) score between the two groups, and to evaluate the adverse events (AEs) with the drugs.

RESULTS

After 12 weeks of treatment, both groups showed significant improvements in IPSS scores (total, obstructive and irritative subscores, QoL score) from baseline (p < 0.0001). However, the doxazosin-GITS group showed significantly greater improvements in total IPSS and obstructive subscore than the tamsulosin group in the early period (p < 0.05). Improvements in irritative subscore (within 4 weeks) and QoL score (during 12 weeks) were not significantly different between the groups. The incidences of AEs were similar between the groups.

CONCLUSION

In this study, doxazosin-GITS showed significantly more rapid onset of efficacy and similar AEs compared with tamsulosin in BPH patients with LUTS. We believe this will probably improve patient compliance. Future studies with a larger number of patients and a longer follow-up period will be required to confirm this.

α(1)-Adrenoceptors in the urinary tract

α(1)-Adrenoceptors have been identified and characterized extensively by functional, radioligand-binding, and molecular biological techniques. Molecular clones have been isolated for three α(1)-subtypes (α(1a), α(1b), and α(1d)), and these subtypes are also functionally characterized. α(1)-Adrenoceptors are present in the prostate, urethra, bladder (urothelium, smooth muscle, and afferent nerves), ureter, vas deferens, peripheral ganglia, nerve terminals, vascular tissues, and central nervous system (CNS), and they could all potentially influence overall urinary function and contribute to both the therapeutic and adverse effects of α(1)-adrenoceptor antagonists in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). This review aimed to discuss the relevant physiological and pharmacological roles and molecular biology of α(1)-adrenoceptor subtypes in the prostate, urethra, bladder, ureter, and CNS.

Alpha blockers prior to removal of a catheter for acute urinary retention in adult men

BACKGROUND

Acute urinary retention is a urological emergency in men and requires urgent catheterisation. Any intervention which aims at increasing the rate of a successful trial without a catheter following an acute urinary retention episode would be considered potentially beneficial. Alpha blockers relax prostatic smooth muscle cells thereby decreasing the resistance to urinary flow and by doing so improve urinary symptoms.

OBJECTIVES

To assess the effects of alpha blockers on successful resumption of micturition following removal of a urethral urinary catheter after an episode of acute urinary retention in men.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Register (11 February 2009) and the reference lists of relevant articles. No language or other restrictions were imposed on the searches.

SELECTION CRITERIA

Only randomised and quasi-randomised clinical trials of alpha blockers for trial without a urethral catheter following an episode of acute urinary retention in men were included.

DATA COLLECTION AND ANALYSIS

Both review authors independently examined all the citations and abstracts derived from the search strategy. Any disagreement about trial selection and inclusion was resolved by discussion. A third independent judgement was sought where disagreement persisted. Both review authors extracted independently, cross-checked and processed the data as described in the Cochrane Collaboration Handbook (Higgins 2008).

MAIN RESULTS

Five randomised clinical trials were eligible for inclusion in this review. All five trials compared alpha blockers versus placebo. In four trials alpha blockers were used between 24 to 72 hours (in one study up to a maximum of eight days) before trial without a catheter (TWOC); in one trial alpha blockers were used for eight days prior to trial without a catheter. Four trials tested alfuzosin and one trial tested tamsulosin. Four trials favoured alpha blockers and one trial favoured placebo. Overall rates of successful TWOC tended to favour alpha blockers over placebo. This was statistically significant (RR 1.39, 95% CI 1.18 to 1.64) irrespective of the alpha blocker used (alfuzosin: RR 1.31, 95% CI 1.10 to 1.56; tamsulosin: RR 1.86, 95% CI 1.17 to 2.97).With regard to causing fewer vasodilatation-related side effects (for example hypotension, dizziness), two studies favoured placebo and one favoured alpha blockers. Overall side effects were low for both placebo and alpha blockers. Failure rates were high and mainly caused by the need for re-catheterisation rather than vasodilatation-related side effects.

AUTHORS' CONCLUSIONS

The limited available evidence suggests that alpha blockers increase success rates of TWOC. Alpha blocker side effects are low and comparable to placebo. It is uncertain whether alpha blockers reduce the risk of recurrent urinary retention and need for prostate surgery. The cost effectiveness and recommended duration of alpha blocker treatment after successful TWOC remains unknown. There are a lack of internationally agreed outcome measures for what constitutes successful TWOC. This makes meta-analysis difficult. More randomised clinical trials are needed to address these issues.

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.

Alpha1-adrenoceptor subtypes and lower urinary tract symptoms

Benign prostatic hyperplasia (BPH) is a common cause of urinary outflow obstruction in aging men leading to lower urinary tract symptoms (LUTS). alpha(1)-Adrenoceptors (alpha(1)ARs) antagonists (blockers) have become a mainstay of LUTS treatment because they relax prostate smooth muscle and decrease urethral resistance, as well as relieving bladder LUTS symptoms. A review of key recent clinical trials suggests new insights into the role of specific alpha(1)AR subtypes in the treatment of LUTS.

Naftopidil, a selective alpha-1 adrenoceptor antagonist, inhibits growth of human prostate cancer cells by G1 cell cycle arrest

Alpha-1 adrenoceptor antagonists are generally prescribed for benign prostate hyperplasia with lower urinary tract symptoms. Naftopidil, a selective alpha-1 adrenoceptor antagonist, is frequently used in Japan because it has fewer side effects. Here we demonstrate for the first time that naftopidil has growth inhibitory effect in androgen-sensitive and -insensitive human prostate cancer cell lines. The concentrations causing 50% inhibition (IC50) of cancer cell growth were 22.2 +/- 4.0 microM in androgen-sensitive LNCaP cells and 33.2 +/- 1.1 microM in androgen-insensitive PC-3 cells. FACS analysis revealed that cell growth inhibition by naftopidil was due to the arrest of the G1 cell cycle. Expressions of p27(kip1) and p21(cip1) were significantly increased in LNCaP cells treated with naftopidil. In PC-3 cells, naftopidil induced p21(cip1) but not p27(kip1). In vivo, oral administration of naftopidil to nude mice inhibited the growth of PC-3 tumors as compared to vehicle-treated controls. These results suggest that naftopidil may be useful in the chemoprevention of prostate cancer and the intervention of hormone refractory prostate cancer.

Impact of physicochemical and structural properties on the pharmacokinetics of a series of alpha1L-adrenoceptor antagonists

A rational drug discovery process was initiated to design a potent and prostate-selective alpha1(L)-adrenoceptor antagonist with pharmacokinetic properties suitable for once a day administration after oral dosing, for the treatment of benign prostatic hyperplasia. Two series of compounds based on a quinoline or quinazoline template were identified with appropriate pharmacology. A series of high molecular weight cations with high hydrogen-bonding potential had extensive in vivo clearance, despite demonstrating metabolic stability. Studies in the isolated perfused rat liver and fresh rat hepatocytes indicated that active transport protein-mediated hepatobiliary elimination is an efficient clearance process for these compounds. A reduction in molecular weight and hydrogen-bonding potential resulted in a second series of compounds with in vivo hepatic clearance predictable from in vitro metabolic clearance. Initially, lipophilicity was reduced within this second series to reduce metabolic clearance and increase elimination half-life. However, this strategy also resulted in a concomitant reduction in volume of distribution and a negligible effect on prolonging half-life. An alternative strategy was to increase the intrinsic metabolic stability of the molecule by careful structural modifications while maintaining lipophilicity. Replacement of the metabolically vulnerable morpholine side chain resulted in identification of UK-338,003, (N-[2-(4-amino-6,7-dimethoxy-5-pyridin-2-yl-quinazolin-2-yl)-1,2,3,4-tetrahydro-isoquinolin-5-yl]-methanesulfonamide), which fulfilled the objectives of the discovery program with suitable pharmacology (human prostate alpha1(L) pA(2) of 9.2 with 25-fold selectivity over rat aorta alpha1(D)) and sufficiently long elimination half-life in human volunteers (11-17 h) for once a day administration.

Doxazosin gastrointestinal therapeutic system versus tamsulosin for the treatment of benign prostatic hyperplasia: a study in Chinese patients

AIM

The efficacy and safety profiles of two alpha1-adrenoceptor antagonists, doxazosin gastrointestinal therapeutic system, a controlled-release formulation of doxazosin, and tamsulosin, were compared in Chinese men with confirmed benign prostatic hyperplasia.

METHODS

After a 2-week placebo run-in phase, 117 patients were randomized to daily treatment with doxazosin gastrointestinal therapeutic system (4 mg doxazosin) (n = 60) or 0.2 mg tamsulosin (n = 57) for 6 weeks with no titration of study medications. Efficacy was measured by the International Prostate Symptom Score, maximum urinary flow rate, postvoid residual urine volume, and quality-of-life score from the International Prostate Symptom Score. Adverse events were recorded.

RESULTS

Both drugs significantly improved the International Prostate Symptom Score (total, irritative subscore and obstructive subscore) and maximum urinary flow rate. Doxazosin gastrointestinal therapeutic system reduced postvoid residual urine volume significantly more than tamsulosin (-25 +/- 5 mL vs 2 +/- 5 mL, P = 0.041) in patients with residual volume >0 mL at baseline. Other differences between groups were not statistically significant.

CONCLUSIONS

The doxazosin gastrointestinal therapeutic system and tamsulosin were effective and well tolerated for the treatment of benign prostatic hyperplasia in Chinese men.

Alpha1 Adrenoceptors in Human Urinary Tract: Expression, Distribution and Clinical Implications

Adrenergic receptors (ARs) are a class of proteins belonging to the G protein-coupled receptor family. Pharmacological and molecular studies allowed dividing ARs into three different categories: α1, α2 and β. In this review, we focused on α1 ARs and α1 AR antagonists, since α 1 ARs play an important role in the pathophysiology of a number of urinary tract (UT) dysfunctions. α1 ARs are widely expressed in human UT; in particular, the three ureter areas (distal, medial and proximal) show different patterns of receptor expression (i.e. distal > medial = proximal), giving the molecular basis for the use of α1 ARs antagonist in the expulsive therapy of distal ureter calculi. Bladder areas are characterized by important differences among trigone, detrusor and neck, the first showing a different pattern of expression compared to the other parts. Further, there are evidences of both density and subtype gender-dependent expressions. α1 ARs expression in prostate and detrusor is a widely investigated area of research, mainly due to the clinical impact of benign prostatic hyperplasia (BPH). Urethra has not been well studied in human, although it plays a role in the control of continence.

Studies carried out on α1 AR subtype expression in the UT indicate that, although the presence of each subtype is observed, α1A firstly and then α1D ARs seem to be more expressed than α1B ARs. Thus, drugs that demonstrate high α1A/D AR selectivity have drawn the researchers’ attention. As it relates specifically to the α1 AR antagonists used in the treatment of lower UT symptoms, the concept of uroselectivity has been operationally defined; indeed, in a number of recent publications uroselectivity has been defined as the degree to which a given compound inhibits norepinephrine-induced increase in urinary muscle contractions and/or its propensity to generate unwanted cardiovascular effects, such as decreases in blood pressure.

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.

Linguistic adaptation and validation of the Spanish version of the Benign Prostatic Hyperplasia-Patient Impact Measure (BPH-PIM)

BACKGROUND

The Benign Prostatic Hyperplasia-Patient Impact Measure (BPH-PIM) is a self-reported quality-of-life questionnaire for measuring the impact of urinary/prostate symptoms on the quality of life of patients with BPH. The aim of the present study was to adapt the original instrument to Spanish (for use in Spain) and to assess the psychometric properties of the new version.

METHODS

Linguistic adaptation was performed using the standard processes for establishing conceptual equivalence, and was partially conducted in parallel with original instrument development. Psychometric properties were assessed on a sample of 131 patients with BPH who were receiving treatment with doxazosin gastrointestinal therapeutic system (GITS).

RESULTS

All the standardised items had response rates > 99%; there were no floor or ceiling effects. Reliability in terms of Cronbach's alpha was 0.96 and the intraclass correlation coefficient was 0.97. Construct validity was confirmed by factor analysis. Convergent validity was confirmed in terms of the relationship to the 12-Item Short-Form Health Survey (SF-12) [p < 0.001], Health Utilities Index Mark III (HUI-3) [p < 0.001] and the International Prostate Symptom Score (IPSS) QOL item (p < 0.001). The instrument showed discriminant validity, in terms of IPSS groups (p < 0.001). The instrument was sensitive to change in terms of the correlation of the domain scores of the PIM to improvements in symptom scores (p < 0.001). Significant differences were observed for those who improved > or = 3 points in the IPSS scale (p < 0.001).

CONCLUSION

A psychometrically valid and conceptually equivalent version of the BPH-PIM questionnaire has been produced in Spanish to be used in Spain in patients with BPH.

Three months' treatment with the alpha1-blocker alfuzosin does not affect total or transition zone volume of the prostate

Treatment with alpha(1)-adrenergic receptor blockers improves lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia. This study was conducted to test the hypothesis that induction of apoptosis in prostate tissue could be a mechanism underlying the observed clinical benefit. This placebo-controlled, double-blind, randomized trial enrolled 536 men with LUTS who were treated with alfuzosin (10 or 15 mg) once daily or placebo for 3 months. Total prostate and transition zone volume was measured by standardized transrectal ultrasound measurements at baseline and 3 months. Total prostate volume increased by 0.4 ml from baseline in placebo patients but decreased by -0.25 ml in the combined alfuzosin groups. Percentage change was not statistically significantly different between the placebo and alfuzosin groups. Changes in transition zone volumes from baseline were similar in both treatment arms; percentage change was not statistically significantly different between the placebo and alfuzosin groups. Volume changes did not correlate with prostate volumes at baseline. Overall, neither total prostate nor transition zone volume increased or decreased systematically within the 3-month treatment period. If alfuzosin-induced apoptosis in prostate tissue, it was not evident by a measurable change in prostate volume after 3 months' treatment. Further analysis at 1 and 2 years will determine the effect of longer-term treatment.

Clinical efficacy and tolerability of alpha-blocker doxazosin as add-on therapy in patients with hypertension and impaired glucose metabolism

BACKGROUND AND AIM

The aim of this trial was to evaluate the effect of doxazosin as add-on therapy in patients with hypertension not adequately controlled on current antihypertensive therapy, and impaired glucose metabolism. The effect of doxazosin administered as add-on therapy was to be considered significant both from clinical and statistical viewpoints if the proportion of patients with adequate control of blood pressure (BP<130/85 mmHg) would be at least 30% after 16 weeks of combined therapy.

METHOD AND RESULTS

It was an open, multicenter phase IV study, lasting 19 weeks: 3-week qualifying/placebo run-in period+16-week dose titration/add on therapy period, involving 264 out-patients (158 m and 106 f; mean age+/-SD: 60.9+/-8.6 years; mean BMI+/-SD: basal 29.5+/-5.1, final 30.2+/-4.6) with blood pressure still >130/85 mmHg in spite of the antihypertensive treatment (ACE inhibitors 44%, AT II antagonists 21%, Ca antagonists 12%, other drugs 8%, polytherapy 15%) and affected by type 2 diabetes (n=219), impaired fasting glucose (IFG; n=16) or impaired glucose tolerance (IGT; n=29). Following a run-in, 3-week qualifying phase during which placebo was added to ongoing antihypertensive treatment, 16-week treatment with doxazosin was added at dosages from 1 up to 8 mg/day. Main outcome measures were: the percentage of patients with blood pressure <130/85 mmHg at the end of treatment; the effects of the combination therapy on glyco-lipidic metabolism: fasting plasma glucose, fasting insulin, glycated hemoglobin, insulin resistance (HOMA-R), plasma lipids; and the effect on the 10-year CHD risk (Framingham equation).

RESULTS

35% of patients were responsive (BP<130/85 mmHg) to add-on treatment with doxazosin (CI 90%: 30.3%-40.4%; P<0.05, stat. an. intention to treat). During the run-in phase with placebo, mean SBP/DBP (+/-SD) decreased from 155.6+/-13.2/91.8+/-6.8 mmHg (Week -3) to 151.9+/-12.9/90.1+/-7.2 mmHg (Week -1) and to 151.2+/-11.5/90.1+/-6.9 mmHg (Week 0). During add-on treatment with doxazosin, mean SBP/DBP (+/-SD) further decreased to 144.9+/-15.2/86.3+/-8.3 mmHg (Week 4), 139.7+/-15.3/83.4+/-7.9 mmHg (Week 8), 135.5+/-14.3/81.7+/-7.6 mmHg (Week 12) and 136.4+/-14.5/81.0+/-7.0 mmHg (Week 16). Overall, mean BP changes reached a plateau of about -15 mmHg (SBP) and -9 mmHg (DBP) after 16 weeks of treatment; at each visit the mean decreases from baseline were statistically significant. The following mean values of metabolic parameters were reduced during the study: fasting plasma glucose (-4.1mg/dl; -2.8%), fasting insulin (-2 microU/ml; -12.3%; P<0.05), glycated hemoglobin (-0.12%; -1.7%), HOMA-R (-1.03; -18.2%; P<0.05), total cholesterol (-1.85 mg/dl; -1.1%), LDL cholesterol (-1.35 mg/dl; -0.8%) and triglycerides (-5.64 mg/dl; -2.4%); mean HDL cholesterol increased (+1.79 mg/dl; +3.9%; P<0.01). At the end of study treatment, the percentage of patients with lab values returned within normal ranges, in comparison with basal values, was statistically significant (P<0.05) for the following parameters: fasting plasma glucose (6.3%), fasting insulin (7.5%), LDL cholesterol (6.0%). Ten-year CHD risk (+/-SD) decreased from 16.4+/-7.8% to 13.6+/-7.4% (final vs. basal: -2.87+/-3.9; -17%; P<0.01). Six patients (2.3%) reported 8 adverse drug reactions: dizziness (3), edema (2), headache (2), asthenia (1). In one out of these 6 patients, in whom doxazosin was associated to the ACE inhibitor quinapril, adverse reaction (peripheral edema) led to treatment withdrawal.

CONCLUSION

In patients not responsive to antihypertensive treatment and concomitantly affected by impaired glucose metabolism, achievement of target BP was obtained in more than one third of cases after 16-week add-on treatment with doxazosin. Changes in glyco-lipidic parameters and reduction of 10-year CHD risk observed during the study, although of moderate extent, confirm the overall favourable effect of antihypertensive combinations including doxazosin.

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.

Validation and pharmacokinetic application of a method for determination of doxazosin in human plasma by high-performance liquid chromatography

A simple high-performance liquid chromatographic method for the determination of doxazosin in human plasma was developed and validated. Prazosin was used as internal standard. After extraction twice with ethyl acetate, chromatographic separation of doxazosin in human plasma was carried out using a reversed-phase Apollo C18 column (250 x 4.6 mm, 5 microm) with mobile phase of methanol-acetonitrile-0.04 m disodium hydrogen orthophosphate (22:22:56, v/v/v) adjusted to pH 4.9 with 0.9 m phosphoric acid and quantified by fluorescence detection operated with an excitation wavelength of 246 nm and an emission wavelength of 389 nm. The lower limit of quantification (LLOQ) of this assay was 1 ng/mL using 500 microL human plasma. Linearity was established over the range 1-25 ng/mL (r2 > 0.9994). The intra- and inter-day accuracy ranged from 90.5 to 104.4% and the coefficient of variation were not more than 8.6% for both intra- and inter-day precision, over the range of the calibration curve. The absolute recoveries of doxazosin and prazosin from human plasma were more than 91%. Doxazosin demonstrated acceptable short-term, long-term and freeze-thaw stability in human plasma. The assay has been successfully applied to plasma sample ana-lysis for pharmacokinetic study.

High-performance liquid chromatographic determination of doxazosin in human plasma for bioequivalence study of controlled release doxazosin tablets

A highly sensitive high-performance liquid chromatographic quantification method with fluorescence detection was developed and validated for the determination of doxazosin in human plasma. The developed method employed one-step extraction of doxazosin from plasma matrix with ethyl acetate using propranolol as an internal standard. Chromatographic separation was obtained within 8.0 min using a reverse-phase Capcell-Pak C(18) column (150 x 4.6 mm i.d., 5 microm) and the mobile phase consisted of methanol-water containing 10 mM perchloric acid and 1.8 mM sodium heptane sulfonic acid (50:50, v/v) and was set at a flow rate of 1.5 mL/min. The calibration curve constructed was linear in the range of 0.3-50.0 ng/mL. The proposed method achieved a lower limit of quantification of 0.3 ng/mL, better than the reported HPLC methods. Average recoveries of doxazosin and the internal standard from human plasma matrix were 87.0 and 85.9%, respectively. The present method was validated by evaluating the precision and accuracy for inter- and intraday variation in the concentration range 0.3-50 ng/mL. The precision values expressed as relative standard deviations in the inter- and intraday validation were 1.17-6.29 and 0.84-5.94%, respectively. This method was successfully applied to the bioequivalence study of two doxazosin controlled release tablets in healthy, male human subjects.