[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.