Comparison of doxazosin with or without tolterodine in men with symptomatic bladder outlet obstruction and an overactive bladder

OBJECTIVE

To assess the efficacy of combined treatment with doxazosin and tolterodine, as although alpha-blockers are commonly used and generally effective in men with symptomatic bladder outlet obstruction (BOO), a subset of men with BOO and overactive bladder (OAB) symptoms often complain of persistent symptoms.

PATIENTS AND METHODS

In a prospective study of 144 consecutive men with BOO at one tertiary urology centre, all had a baseline pressure-flow urodynamic study and were then subdivided into those with BOO or BOO + OAB, based on absence or presence of involuntary detrusor contractions. The Abrams-Griffiths nomogram was used to determine obstructive BOO. After the initial evaluation, all patients were treated with doxazosin 4 mg/day for 3 months. In patients with no symptomatic improvement, tolterodine 2 mg twice daily was added for an additional 3 months.

RESULTS

Of the 144 patients, 76 (53%) were diagnosed as having BOO and 68 (47%) BOO + OAB. The patients with BOO + OAB were older (P < 0.05) and had a higher International Prostate Symptom Score. After 3 months of treatment with doxazosin, 60 (79%) with BOO and 24 (35%) BOO + OAB reported a symptomatic improvement. In those patients with no improvement, six of 16 with BOO and 32 of 44 (73%) with BOO + OAB improved after adding tolterodine. Acute urinary retention developed in only two of 60 men (3.3%) treated with the combined therapy.

CONCLUSION

About half of men with symptomatic BOO had an OAB; while about three-quarters of men with symptomatic BOO and no OAB improved with doxazosin, only a third with BOO + OAB were helped with doxazosin alone. Combining tolterodine with doxazosin was effective in three-quarters of men with BOO + OAB. Overall, most men with BOO with or with no OAB were helped with doxazosin alone or with the addition of tolterodine.

Antihypertensive effect of alpha- and beta-adrenergic blockade in obese and lean hypertensive subjects

The purpose of this study was to determine the contribution of the adrenergic system in mediating hypertension in obese and lean patients. Thirteen obese, hypertensive patients with a body mass index (BMI) > or =28 kg/m2 (obese) and nine lean patients with a BMI < or =25 kg/m2 (lean) were recruited. After a 1-week washout period, participants underwent daytime ambulatory blood pressure monitoring (ABPM). Participants were then treated with the alpha-adrenergic antagonist doxazosin, titrating to 4 mg QHS in 1 week. In the next week, the beta-adrenergic antagonist atenolol was added at an initial dose of 25 mg/day and titrated to 50 mg/day within 1 week. One month after the addition of atenolol, all patients underwent a second ABPM session. There were no differences between the obese and lean subjects in baseline systolic (SBP), diastolic (DBP), or mean arterial pressures (MAP) measured by office recording or ABPM. However, obese subjects had higher heart rates than lean subjects (87.5+/-2.4 v 76.8+/-4.9 beats/min). After 1 month of treatment with the adrenergic blockers, obese patients had a significantly lower SBP (130.0+/-2.5 v 138.9+/-2.1 mm Hg, P = .02) and MAP (99.6+/-2.3 v 107.0+/-1.5 mm Hg, P = .02) than lean patients. Obese patients also tended to have a lower DBP than lean patients (84.3+/-2.5 v 90.9+/-1.6 mm Hg, P = .057), but there was no significant difference in heart rate after 1 month of adrenergic blockade. These results indicate that blood pressure is more sensitive to adrenergic blockade in obese than in lean hypertensive patients and suggest that increased sympathetic activity may be an important factor in the maintenance of hypertension in obesity.

Changes of nocturnal blood pressure dipping status in hypertensives by nighttime dosing of alpha-adrenergic blocker, doxazosin : results from the HALT study

Abnormal nocturnal blood pressure (BP) dipping status may be partly determined by nocturnal sympathetic activity. We studied the effect of nighttime dosing of an alpha(1)-adrenergic blocker, doxazosin, on the BP dipping status of 118 hypertensives, all of whom underwent 24-hour ambulatory BP monitoring before and after treatment. The mean nighttime/daytime ratio of systolic BP was increased (0.91 after therapy versus 0.89 at baseline, P<0.05). The patients were initially divided into 4 groups on the basis of their dipping status at the baseline assessment: 18 (15%) were extreme dippers, with a nighttime systolic BP fall of at least 20% of daytime BP; 46 (39%) were dippers (fall between 10% and 20%); 48 (41%) were nondippers (fall between 0% and 10%); and 6 (5%) were risers (nocturnal increase of systolic BP). A shift in dipping status toward less nocturnal BP dipping was observed after doxazosin therapy (P<0.05). Dipping status was determined by nighttime more than by daytime BP, and this was not explained by differences in the number of daytime and nighttime readings. The effects of doxazosin on the mean nocturnal systolic BP changes were an increase of 4.3 mm Hg in extreme dippers and decreases of 0.7 mm Hg in dippers, 12 mm Hg in nondippers, and 18 mm Hg in risers; the reduction was only significant in the latter 2 groups (both P<0.01). To estimate the effects of regression to the mean on the changes in dipping status, we also defined dipping status with the average of the BPs before and after doxazosin and found no difference in the degree of nighttime BP reduction among each group. The reduction of daytime BP was now significantly greater in the subgroups with less dipping: 6. 4 mm Hg for extreme dippers and 16 mm Hg for risers (P<0.05). In conclusion, nighttime dosing with doxazosin markedly affects the nocturnal BP dipping status of hypertensives, but the apparently greater reduction in nighttime pressure in nondippers and risers may be, at least partly, due to the effect of regression to the mean. The most important determinants of the effect of doxazosin were the absolute BP levels, both day and night, rather than dipping status per se.

Combination Therapy With Doxazosin and Finasteride for Benign Prostatic Hyperplasia in Patients With Lower Urinary Tract Symptoms and a Baseline Total Prostate Volume of 25 Ml or Greater

PURPOSE

We examined data from the Medical Therapy of Prostatic Symptoms trial to determine the relationship between baseline TPV and the effect of medical therapy in men with LUTS secondary to BPH.

MATERIALS AND METHODS

A total of 3,047 patients with LUTS were randomized to placebo, 4 to 8 mg doxazosin, 5 mg finasteride or the combination of doxazosin and finasteride. Average treatment duration was 4.5 years The primary outcome was time to overall clinical progression of BPH, defined as a confirmed 4 point or greater increase in AUA SS, acute urinary retention, incontinence, renal insufficiency or recurrent urinary tract infection. Secondary outcomes were the need for invasive therapy for BPH, and changes in AUA SS and the maximum urinary flow rate with time. TPV was measured by transrectal ultrasound at baseline and study end.

RESULTS

In patients with a small prostate (baseline TPV less than 25 ml) combination therapy was no better than doxazosin alone for decreasing the risk of clinical progression of BPH and need for invasive therapy as well as improving AUA SS and the maximum urinary flow rate. However, in patients with moderate size (25 to less than 40 ml) or enlarged (40 ml or greater) glands combination therapy led to a clinical benefit in these outcomes that was superior to that of doxazosin or finasteride.

CONCLUSIONS

Combination therapy with doxazosin and finasteride led to a greater decrease in the risk of clinical progression of BPH than either drug alone in patients with LUTS with a baseline TPV of 25 ml or greater.

Efficacy and safety of doxazosin for perioperative management of patients with pheochromocytoma

Despite adverse side effects, phenoxybenzamine has been widely used for the preoperative management of patients with pheochromocytoma. Doxazosin, a specific a 1-adrenoceptor antagonist, has a pharmacologic profile more suited to controlling blood pressure in such patients. A sequential study of 35 patients with pheochromocytoma encompassed a definite and prescribed change in preoperative drug management from phenoxybenzamine to doxazosin. Hemodynamic, pharmacologic, and biochemical indicators of a- and b-adrenoceptor blockade were measured before, during, and after anesthesia and surgery in 8 patients pretreated with phenoxybenzamine and 27 patients pretreated with doxazosin. Doxazosin (2-16 mg/day) was as effective as phenoxybenzamine in controlling arterial pressure and heart rate before and during surgery, but doxazosin caused fewer undesirable side effects both before and after surgery. Following phenoxybenzamine therapy substantial a 1-adrenoceptor blockade, detected as a right shift of phenylephrine dose-response curves, persisted for more than 2 days postoperatively, whereas after doxazosin it was undetectable on the first postoperative day. Doxazosin provided safe, efficacious pre- and perioperative control of arterial pressure. In patients with predominantly norepinephrine-secreting tumors, pretreatment 24-hour urinary norepinephrine excretion gave an indication of the daily doxazosin requirement.

COMBINATION TREATMENT WITH PROPIVERINE HYDROCHLORIDE PLUS DOXAZOSIN CONTROLLED RELEASE GASTROINTESTINAL THERAPEUTIC SYSTEM FORMULATION FOR OVERACTIVE BLADDER AND COEXISTING BENIGN PROSTATIC OBSTRUCTION: A PROSPECTIVE, RANDOMIZED, CONTROLLED MULTICENTER STUDY

PURPOSE

We evaluated the efficacy and safety of a therapeutic modality involving propiverine combined with doxazosin in patients with overactive bladder (OAB) and benign prostatic obstruction.

MATERIALS AND METHODS

Men 50 years or older with OAB symptoms and urodynamically proven bladder outlet obstruction (Abrams-Griffith score greater than 20) were randomized (1:2) into 2 groups, namely group 1-doxazosin controlled release gastrointestinal therapeutic system formulation (4 mg once daily) only and group 2-propiverine hydrochloride (20 mg once daily) plus doxazosin controlled release gastrointestinal therapeutic system formulation for an 8-week treatment regimen.

RESULTS

A total of 211 men, including 69 in group 1 and 142 in group 2, were treated and 198 (93.8%) completed the 8 weeks of treatment. Significant improvements were noted in each group after treatment in urinary frequency, maximum flow rate, average micturition volume and International Prostate Symptom Score. Compared with group 1 improvement rates with regard to urinary frequency (23.5% vs 14.3%, p = 0.004), average micturition volume (32.3% vs 19.2%, p = 0.004), and storage (41.3% vs 32.6%, p = 0.029) and urgency (p = 0.019) International Prostate Symptom Score symptoms were more significant in group 2. Post-void residual urine was found to be significantly increased only in group 2 but this was not accompanied by urinary retention. Patient satisfaction rates were found to be significantly higher in group 2 than in group 1 (p = 0.002). Overall adverse event rates were higher in group 2 (p = 0.002), although discontinuation rates and discontinuation rates due to adverse events were not different between the 2 groups.

CONCLUSIONS

This study reveals that combination therapy consisting of alpha1-adrenoceptor antagonists with antimuscarinics represents an effective and relatively safe treatment modality in select patients with OAB coexisting with benign prostatic obstruction.

Morning blood pressure surge and hypertensive cerebrovascular disease: role of the alpha adrenergic sympathetic nervous system

BACKGROUND

The morning surge of blood pressure (BP) is associated with alpha-adrenergic activity. We studied the association between the alpha-adrenergic morning surge in BP and silent cerebrovascular disease in elderly patients with hypertension.

METHODS

We conducted ambulatory BP monitoring three times (twice at baseline and after nighttime dosing of the alpha1-blocker doxazosin) in 98 elderly hypertensive patients in whom the presence of silent cerebral infarcts (SCI) was assessed by brain magnetic resonance imaging. The morning BP surge (MBPS) was calculated as the mean systolic BP during the 2 h after waking minus the mean systolic BP during 1 h that included the lowest sleep BP. The alpha-adrenergic MBPS was calculated as the reduction of MBPS by doxazosin.

RESULTS

The prevalence of multiple SCI was higher in the Surge group (top quartile: MBPS > or = 45 mm Hg, n = 24) than in the Nonsurge group (MBPS < 45 mm Hg, n = 74) (54% v 31%, P = .04), and in the higher alpha-adrenergic surge group (top quartile: alpha-adrenergic MBPS > or = 28 mm Hg, n = 25) than in the lower alpha-adrenergic surge group (< 28 mm Hg, n = 73) (68% v 26%, P < .0001). In the Surge group, subjects with higher alpha-adrenergic surge (n = 17) had a markedly higher frequency of multiple SCI, whereas none in the lower alpha-adrenergic surge group had multiple SCI (n = 7) (77% v 0%, P = .001). The alpha-adrenergic MBPS was closely associated with multiple SCI (10 mm Hg increase: OR = 1.96, P = .006), independently of age, MBPS, 24-h systolic BP, and other confounding factors.

CONCLUSION

The morning BP surge, particularly that dependent on alpha-adrenergic activity, is closely associated with advanced silent hypertensive cerebrovascular disease in elderly individuals.

Pharmacogenetic association of the angiotensin-converting enzyme insertion/deletion polymorphism on blood pressure and cardiovascular risk in relation to antihypertensive treatment: the Genetics of Hypertension-Associated Treatment (GenHAT) study

BACKGROUND

Previous studies have reported that blood pressure response to antihypertensive medications is influenced by genetic variation in the renin-angiotensin-aldosterone system, but no clinical trails have tested whether the ACE insertion/deletion (I/D) polymorphism modifies the association between the type of medication and multiple cardiovascular and renal phenotypes.

METHODS AND RESULTS

We used a double-blind, active-controlled randomized trial of antihypertensive treatment that included hypertensives > or =55 years of age with > or =1 risk factor for cardiovascular disease. ACE I/D genotypes were determined in 37 939 participants randomized to chlorthalidone, amlodipine, lisinopril, or doxazosin treatments and followed up for 4 to 8 years. Primary outcomes included fatal coronary heart disease (CHD) and/or nonfatal myocardial infarction. Secondary outcomes included stroke, all-cause mortality, combined CHD, and combined cardiovascular disease. Fatal and nonfatal CHD occurred in 3096 individuals during follow-up. The hazard rates for fatal and nonfatal CHD and the secondary outcomes were similar across antihypertensive treatments. ACE I/D genotype group was not associated with fatal and nonfatal CHD (relative risk of DD versus ID and II, 0.99; 95% CI, 0.91 to 1.07) or any secondary outcome. The 6-year hazard rate for fatal and nonfatal CHD in the DD genotype group was not statistically different from the ID and II genotype group by type of treatment. No secondary outcome measure was statistically different across antihypertensive treatment and ACE I/D genotype strata.

CONCLUSIONS

ACE I/D genotype group was not a predictor of CHD, nor did it modify the response to antihypertensive treatment. We conclude that the ACE I/D polymorphism is not a useful marker to predict antihypertensive treatment response.

Clinical pharmacokinetics of doxazosin in a controlled-release gastrointestinal therapeutic system (GITS) formulation

AIMS

A controlled-release gastrointestinal therapeutic system (GITS) formulation of doxazosin mesylate, a long-acting selective alpha1-adrenoceptor antagonist, was developed to enhance the pharmacokinetic profile and simplify the titration schedule by precisely controlling drug delivery rate, permitting an initial dose of 4 mg once daily, compared with standard doxazosin, which is initiated at 1 mg day-1 and titrated to a higher therapeutically effective dose. The aim of the present work was to evaluate the pharmacokinetics and bioavailability of doxazosin GITS with respect to the effect of food, age and gender, and multiple dosing. In addition, in vitro performance was assessed in conditions simulating the gastrointestinal environment.

METHODS

A three-way crossover study in 24 subjects assessed the comparative bioavailability of doxazosin GITS under fed and fasting conditions and doxazosin standard under fasting condition. A multiple-dose, two-way crossover study in 35 subjects assessed the comparative pharmacokinetics and bioavailability of doxazosin GITS and doxazosin standard 4 and 8 mg upon multiple dosing. A multiple-dose, four-parallel-group study was conducted to determine the steady-state pharmacokinetics and bioavailability of doxazosin GITS 4 mg in 41 young and elderly male and female subjects. The release-rate profiles of doxazosin GITS were determined in artificial gastric fluid (pH=1.2), intestinal fluid (pH=7.5), and water. The effect of agitation on the dissolution characteristics of doxazosin GITS in artificial gastric fluid was studied at stirring rates of 50, 75, and 100 rev min-1.

RESULTS

In vitro studies demonstrated that release rates for the GITS tablet are independent of pH in the range of 1.2 (gastric) to 7. 5 (intestinal), and of stirring rates simulating gastrointestinal motility. Clinical pharmacology studies showed that doxazosin GITS had a lower maximum plasma concentration, prolonged time to reach maximum plasma concentration, and a higher minimum plasma concentration compared with doxazosin standard. Thus, the GITS formulation results in a more gradual absorption of doxazosin, and a reduced plasma doxazosin concentration peak-to-trough fluctuation ratio. The relative bioavailability of doxazosin GITS is approximately 60%. With a high-fat meal, the maximum plasma concentration and area under the concentration-time curve were 31% and 18% higher, respectively (P<0.05). Bioequivalence was established between the dose strengths of two 4 mg doxazosin GITS tablets and one 8 mg doxazosin GITS tablet. For both young adult and elderly subjects, and males and females, the pharmacokinetics of doxazosin GITS once daily for 7 days were comparable. Doxazosin GITS was well tolerated in the subjects studied, including young and elderly males and females.

CONCLUSIONS

The GITS formulation of doxazosin enhances the pharmacokinetic profile compared with doxazosin standard, allowing more gradual absorption of doxazosin, and a reduced plasma doxazosin peak-to-trough concentration ratio. Thus, doxazosin GITS therapy can be initiated at a therapeutic dose of 4 mg with reduced haemodynamic side-effects.

Double-blind, placebo-controlled crossover comparison of five classes of antihypertensive drugs

OBJECTIVE

Hypertension guidelines recommend initial treatment with a beta-blocker or diuretic and adding the other drug where blood pressure is not controlled. We hypothesized that systematic rotation through the major classes of antihypertensive drugs would demonstrate substantial differences in the pattern of an individual patient's response, and suggest a more rational approach to choosing best treatment.

DESIGN

Thirty-four young hypertensives (age 28-55, median 47) rotated in a double-blind, Latin-square, crossover fashion through 6 weeks of treatment each with amlodipine, doxazosin, lisinopril, bisoprolol, bendrofluazide and placebo. Blood pressure was measured at each visit. 'Best' drug, defined by efficacy and tolerability, was repeated at the end.

RESULTS

Rotation doubled the number of patients reaching target blood pressure (systolic < 140 mmHg) on one drug (P = 0.03). All five drugs were represented among the 'best' drugs. In six patients, the blood pressure on 'best' drug was at least 10 mmHg lower than on any other. Response to the 'best' drug was highly correlated (r = 0.79) with its previous administration. By contrast, there were only weak correlations between responses to pairs of drugs, except for angiotensin-converting enzyme (ACE) inhibitor (A) with beta-blocker (B), and calcium blocker (C) with diuretic (D) - each r = 0.71, P < 0.005). In these young patients, the majority of patients (23/34) responded best to a drug suppressing the renin system (A and B).

CONCLUSIONS

Patients vary reproducibly in their response to initial treatment, and switching among drugs can increase the efficacy of monotherapy. The results support an AB/CD scheme for choosing therapy, in which the first drug is taken from one of these pairs, and uncontrolled patients switch to one of the other pair.

Nighttime dosing of doxazosin has peak effect on morning ambulatory blood pressure. Results of the HALT Study. Hypertension and Lipid Trial Study Group

In this study the effects of a single daily dose (average 8.9 mg) of doxazosin (an alpha-adrenergic blocker) given at night were evaluated in 111 patients with mild hypertension. Patients were studied first on no medication, and a second time after being treated for up to 16 weeks with doxazosin. Blood pressure was measured by noninvasive ambulatory monitoring at the beginning and end of the study. There was a sustained reduction of both systolic and diastolic pressure throughout the day and night, but the greatest reduction occurred in the morning hours. Since the peak treatment effect was later than predicted from previous pharmacokinetic studies, it is suggested that the timing of the peak effect may depend on the prevailing level of alpha-adrenergic tone, as well as on the pharmacokinetics of the drug.

A combined analysis of double-blind trials of the efficacy and tolerability of doxazosin-gastrointestinal therapeutic system, doxazosin standard and placebo in patients with benign prostatic hyperplasia

OBJECTIVE

To report an integrated analysis of two previous studies fully characterizing the clinical utility of the controlled-release gastrointestinal therapeutic system (GITS) formulation of doxazosin in the treatment of benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Two pivotal randomized, double-blind studies of doxazosin GITS for BPH were assessed by an integrated analysis. Both studies included a 2-week washout period, a 2-week single-blind placebo run-in phase, and a 13-week double-blind treatment phase. One study compared doxazosin GITS, doxazosin standard (-S) and placebo in 795 men; the other compared doxazosin GITS and doxazosin-S in 680 men. Doxazosin GITS was initiated at 4 mg once daily and titrated to 8 mg once daily after 7 weeks, and doxazosin-S was initiated at 1 mg once daily and titrated to a maximum of 8 mg once daily over 7 weeks as needed to achieve optimal symptom control. The primary outcome measures were mean changes from baseline to the final visit for the International Prostate Symptom Score (IPSS) and maximum urinary flow rate (Qmax) in the per-protocol population. Numerous symptom- and urinary-related secondary outcomes were assessed, as were effects of therapy on male erectile dysfunction measured using the International Index of Erectile Function (IIEF) in one study.

RESULTS

Both doxazosin GITS and doxazosin-S significantly improved the symptoms of BPH, as shown by a 45% reduction for each in total IPSS from baseline to final visit, compared with a 34% reduction in patients on placebo. Doxazosin GITS and doxazosin-S produced comparable improvements in Qmax that were significantly greater than with placebo, with a greater improvement sooner after treatment with doxazosin GITS than with doxazosin-S. Nearly half of the patients on doxazosin GITS had symptom relief at the 4-mg starting dose. A similar number of patients in both doxazosin groups were titrated to the maximum dose. Secondary outcomes were consistent with the primary effects. Both doxazosin GITS and doxazosin-S produced significant improvements in sexual function according to IIEF scores among those with dysfunction at baseline. The overall incidence of adverse events was similar among patients treated with doxazosin GITS and placebo, and slightly lower than those on doxazosin-S. There was no apparent difference in the type of adverse events reported for the two formulations of doxazosin, although most adverse events were reported at a lower frequency with doxazosin GITS.

CONCLUSION

Doxazosin GITS is significantly more effective than placebo in reducing the clinical symptoms of BPH and improving Qmax, and as effective as doxazosin-S. Both doxazosin formulations improved sexual function in patients with BPH and sexual dysfunction at baseline. Doxazosin GITS produced a therapeutic effect equivalent to that of doxazosin-S, but with fewer titration steps and a slightly lower overall incidence of adverse events.

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

CONTEXT

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

OBJECTIVE

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

DESIGN

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

SETTING

Multicenter study including 9 centers in The Netherlands.

PATIENTS

134 patients with nonmetastatic PPGL.

INTERVENTION

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Relationship of antihypertensive treatment regimens and change in blood pressure to risk for heart failure in hypertensive patients randomly assigned to doxazosin or chlorthalidone: further analyses from the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial

BACKGROUND

The Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial reported that treatment initiated with doxazosin compared with chlorthalidone doubled the risk for heart failure in high-risk hypertensive patients (relative risk, 2.04 [95% CI, 1.79 to 2.32]). Patients assigned to doxazosin therapy had a mean in-trial systolic/diastolic blood pressure 3/0 mm Hg higher than that in patients assigned to chlorthalidone. Sixty-eight percent (6167 of 9061) of the former patients and 59% (9081 of 15 256) of the latter patients were given additional medications to achieve a target blood pressure of less than 140/90 mm Hg.

OBJECTIVE

To ascertain the influence of open-label antihypertensive drugs and subsequent blood pressure on relative risk for heart failure.

DESIGN

Randomized, double-blind, active-controlled clinical trial.

SETTING

623 sites in the United States and Canada.

PATIENTS

Hypertensive patients 55 years of age or older with at least one additional risk factor for cardiovascular disease.

INTERVENTION

Chlorthalidone (12.5 to 25 mg/d) or doxazosin (2 to 8 mg/d) for a planned follow-up of 4 to 8 years.

MEASUREMENTS

Data on blood pressure, medication, and incident heart failure (treated outside hospital, hospitalized, or fatal) from February 1994 through December 1999.

RESULTS

After the treatment groups were categorized as having no exposure to open-label medications (monotherapy) or exposure to open-label therapy, the relative risk for heart failure with doxazosin versus chlorthalidone was 3.10 (CI, 2.51 to 3.82) and 1.42 (CI, 1.20 to 1.69), respectively. After adjustment for follow-up systolic/diastolic blood pressure, the overall relative risk was 2.00 (CI, 1.72 to 2.32).

CONCLUSION

In high-risk patients with hypertension, the higher risk for heart failure while taking doxazosin compared with chlorthalidone is attenuated but not eliminated by adding other antihypertensive drugs. The small observed difference in systolic blood pressure does not explain this increased risk.

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

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

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.

Combination therapy using oral alpha-blockers and intracavernosal injection in men with erectile dysfunction

OBJECTIVES

Intracavernosal injection with a combination of agents (ie, phentolamine plus papaverine or alprostadil) has been used in an effort to increase efficacy and reduce side effects compared with single agents. The purpose of this pilot study was to determine the potential role of oral alpha-blockers in combination with intracavernosal therapy in men with erectile dysfunction, for whom intracavernosal therapy alone failed.

METHODS

Thirty-eight consecutive men with moderate to severe erectile dysfunction on the basis of history and examination and with minimal or no therapeutic response to intracavernosal alprostadil injection therapy were evaluated. All patients received daily doxazosin titrated to 4 mg over 3 weeks in combination with intracavernosal therapy as needed for 12 weeks. Efficacy was assessed at 4, 8, and 12 weeks after doxazosin titration using the 1 5-item, self-administered International Index of Erectile Function (IIEF) and a global efficacy question (GEQ: Did treatment improve your erections?).

RESULTS

For the group, the mean baseline IIEF score before therapy was 29.7+/-9.8. After intracavernosal therapy (mean dose 34.7+/-7.3 microg), IIEF improved to 36.1+/-1 1.4 (17.7%). After addition of doxazosin, IIEF improved to 48.6+/-13.4, 46.4+/-10.9, and 51.5+/-14.3 at 4, 8, and 12 weeks, respectively (P < 0.01). The GEQ response improved from 25.7% at baseline to 81.4% at 12 weeks. Overall 22 (57.9%) of 38 patients with the combined regimen had a significant (more than 60% improvement in IIEF) therapeutic response.

CONCLUSIONS

The addition of an oral alpha-blocker may have a beneficial effect in patients with erectile dysfunction for whom intracavernosal therapy alone fails. The synergistic effects of vascular dilation and blockade of sympathetic inhibition may explain this response. The potential role of alpha-blockade in synergy with other agents designed to treat erectile dysfunction remains to be determined.

Efficacy of extended-release doxazosin and doxazosin standard in patients with concomitant benign prostatic hyperplasia and sexual dysfunction

OBJECTIVE

To report a comprehensive retrospective analysis of the favourable effects of doxazosin extended-release (XL) and doxazosin standard on the sexual health of patients with comorbid benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), augmenting a previous study of 680 patients with symptomatic BPH.

PATIENTS AND METHODS

Men with BPH and aged 50-80 years participated in a randomized, double- blind, double-dummy, parallel-group, multicentre trial, completing a 2-week, single-blind, placebo run-in period before receiving doxazosin XL 4 or 8 mg once daily or doxazosin standard 1-8 mg once daily for 13 weeks. Baseline sexual function and changes from baseline after treatment with doxazosin were evaluated from responses of the International Index of Erectile Function (IIEF) questionnaire (with dysfunction defined as a score of < or = 3 for any question) and the five domains for erectile function (intercourse satisfaction, orgasmic function, sexual desire and overall sexual satisfaction).

RESULTS

Of 680 patients randomized into the trial, 237 (35%) had ED at baseline; in these patients there were statistically and clinically significant improvements in each of the five IIEF domains with XL and standard doxazosin (P < or = 0.0019), with the range of improvement being from 13% to 41%. There were no significant differences between treatment groups. Doxazosin XL consistently improved sexual function, as assessed by the individual questions of the IIEF questionnaire. There was no statistically significant difference between groups for any sexual function question analysed.

CONCLUSION

Doxazosin XL and standard improved sexual function in men with concomitant BPH and ED at baseline. This may represent an action independent of relieving lower urinary tract symptoms, because the beneficial effect of doxazosin was reported in patients with no symptomatic BPH.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

CLINICAL TRIAL REGISTRATION

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

Effect of doxazosin on rat urinary bladder function after partial outlet obstruction

Hypoxia induced by partial outlet obstruction is believed to play a major role in both the hypertrophic and degenerative effects of partial outlet obstruction. Doxazosin (dox) is a clinically effective alpha-adrenergic antagonist used in the treatment of symptomatic benign prostatic hyperplasia (BPH). Although the major therapeutic effect of the agent is believed to occur on the smooth muscle components of the prostate by reducing prostatic urethral resistance and thus improving emptying, dox may have part of its clinical action via effects mediated by other actions, including via spinal alpha-adrenergic receptors or direct effects on the bladder, possibly via inhibition of vascular alpha receptors. The specific aim of the current study was to determine whether dox pretreatment on rats affects blood flow to the bladder and reduces the level of bladder dysfunction induced by partial outlet obstruction. In part 1, eight rats were separated into two groups of four rats each. Group 1 received oral administration of dox (30 mg/kg) for 4 weeks; group 2 received vehicle (5% dimethyl sulfoxide). After 4 weeks of treatment, blood flow studies were performed using fluorescent microspheres and the bladders excised, frozen, and submitted to Interactive Medical Technologies (IMT) for blood flow analysis. In part 2, 32 adult male rats were separated into four groups of eight rats each. Groups 1 and 2 received oral administration of dox (30 mg/kg) for 4 weeks, groups 3 and 4 received vehicle (5% dimethyl sulfoxide). At 4 weeks, the rats in groups 1 and 3 received partial outlet obstructions and treatment continued for an additional 2 weeks. After 6 weeks of treatment (total), each rat was anesthetized, the bladder excised, weighed, and isolated strips mounted and contractility studies performed. 1) Four weeks pretreatment of rats with dox increased blood flow to the bladder in both the control and obstructed groups. 2) Partial outlet obstruction induced a mild decrease in blood flow. 3) The magnitude of the increased bladder weight in the vehicle-treated obstructed group was significantly greater than in the dox-treated obstructed group. 4) Partial outlet obstruction resulted in significant decreases in the contractile response to field stimulation in both treated and non-treated rats. The magnitude of the decreased response was significantly greater in the non-treated rats. 5) The response to potassium chloride was significantly reduced by partial outlet obstruction in the vehicle-treated group but not in the dox-treated group. 6) The time to maximal tension was significantly increased in response to carbachol, adenosine triphosphate, and potassium chloride. However, the magnitude of the increase was significantly greater for the vehicle-treated obstructed groups stimulated by potassium chloride than for the dox-treated groups. Dox treatment of rats increased blood flow to the bladder and reduced the severity of the response to partial outlet obstruction. These beneficial effects would be due to pharmacological effects on alpha-adrenergic systems outside those present in the prostate. These include effects on blood flow to the bladder, effects on the micturition centers of the central nervous system, spinal reflexes, and alpha-adrenergic receptors in the urethra and bladder.

A randomized, double-blind crossover study of tamsulosin and controlled-release doxazosin in patients with benign prostatic hyperplasia

OBJECTIVE

To compare the effects of the doxazosin gastrointestinal therapeutic system, extended-release (doxazosin-GITS) formulation, and tamsulosin, another alpha1-antagonist, on total International Prostate Symptom Score (IPSS) and maximum urinary flow rate (Qmax) in treating patients with benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Data were analysed from a prospective, randomized, double-blind, crossover study of men aged 50-80 years with concomitant BPH and hypertension as inclusion criteria. Fifty-two men were treated in four phases: phase I, placebo run-in for 2 weeks; phase II, first study drug doxazosin-GITS or tamsulosin for 8 weeks; phase III, washout with placebo for 2 weeks; and phase IV, second study drug tamsulosin or doxazosin-GITS for 8 weeks. Doxazosin-GITS was started at 4 mg/day and tamsulosin at 0.4 mg/day, and then titrated to 8 mg/day and 0.8 mg/day, respectively, after 4 weeks of therapy if the increase in Qmax was < 3 mL/s or the reduction in total IPSS was < 30%. Efficacy assessments included the IPSS and Qmax. Changes in blood pressure were not analysed, as most patients were actually not hypertensive. Endpoint efficacy data were analysed using an analysis of covariance model, with terms for sequence, phase, patients and sequence within patients, in addition to the baseline as covariate. Forty-seven men were treated in both efficacy arms of the study and were evaluable for analysis.

RESULTS

Doxazosin-GITS and tamsulosin significantly relieved lower urinary tract symptoms and significantly increased Qmax from baseline (P = 0.001). Doxazosin-GITS produced significantly greater improvements than tamsulosin in total IPSS (P = 0.019) and obstructive subscores (P = 0.004) at the last treatment visit. The difference between doxazosin-GITS and tamsulosin in improving Qmax approached significance in favour of the former (mean change from baseline 2.6 vs 1.7 mL/s, respectively; between-group difference P = 0.089). Both treatments were well tolerated.

CONCLUSIONS

Treatment with doxazosin-GITS was significantly more effective than tamsulosin in relieving lower urinary tract symptoms.

Combined oral therapy with sildenafil and doxazosin for the treatment of non-organic erectile dysfunction refractory to sildenafil monotherapy

The purpose of this work was to investigate the efficacy and safety of sildenafil in combination with doxazosin for the treatment of non-organic erectile dysfunction in patients who did not respond to sildenafil. We enrolled 28 patients with non-organic erectile dysfunction, for whom 3 months of sildenafil monotherapy had failed. They were divided in two random and homogeneous groups: 14 were treated with doxazosin (4 mg daily) and sildenafil (100 mg 1 h before sexual intercourse); the other 14 patients received sildenafil and placebo. The results were assessed by means of the IIEF questionnaire before the beginning of the study, after 30 days of therapy and after 60 days. Of the 14 patients treated with doxazosin and sildenafil, 11 (78.6%) showed a statistically significant increase of IIEF; in the placebo group, only one patient (7.1%) recorded a significant IIEF increase. The differences observed in the two groups were statistically very significant (P=0.0016). Blood pressure did not show significant alterations. Side effects were minimal and even present during sildenafil monotherapy. The combination therapy with sildenafil and doxazosin resulted in the safe and effective treatment of men with non-organic erectile dysfunction for whom sildenafil alone had failed.

29-week doxazosin treatment in patients with symptomatic benign prostatic hyperplasia. A double-blind placebo-controlled study

In a placebo-controlled study, the safety and efficacy of the selective alpha 1-adrenoceptor-blocking agent doxazosin 4 mg once daily in the symptomatic treatment of benign prostatic hyperplasia (BPH) were evaluated. One hundred patients were primarily included in a 9-weeks study, and after this 75 patients accepted to continue in the present 20 weeks extension. Of the patients in the doxazosin-group (DG) 61% reported overall improvement against 53% in the placebo-group (PG)--(p = 0.56). In the DG, 49% of obstructive symptoms were improved compared to 27% in the PG (p < 0.01), and a reduction of 60% of irritative symptoms was found in the DG against 36% in the PG (p < 0.01). Daytime frequency was reduced by median 1.5 in the DG and remained unchanged in the PG (p < 0.01). Nocturia was reduced by median 1 and 0.5 respectively (p = 0.06). Maximum urinary flow rate (MFR) was improved by median 1.5 ml/s in the DG, while it deteriorated by median 0.5 ml/s in the PG (p < 0.05), Considering postvoid residual urine volume, cystometry variables (first sensation and bladder capacity), changes in sexual function and adverse events there was no difference between the two groups. In conclusion, doxazosin 4 mg once daily in long-term treatment of patients with BPH reduces both obstructive and irritative symptoms, daytime voiding frequency and although only slightly, significantly augments MFR without interference with sexual function and without other serious adverse effects.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial Registration

Clinicaltrials.gov NCT01062945

Anxiety-induced plasma norepinephrine augmentation increases reactive oxygen species formation by monocytes in essential hypertension

BACKGROUND

An association between anxiety and depression and increased blood pressure (BP) and cardiovascular disease risk has not been firmly established. We examined the hypothesis that anxiety and depression lead to increased plasma catecholamines and to production of reactive oxygen species (ROS) by mononuclear cells (MNC) in hypertensive individuals. We also studied the role of BP in this effect.

METHODS

In Protocol 1, a cross-sectional study was performed in 146 hypertensive patients to evaluate whether anxiety and depression affect BP and ROS formation by MNC through increasing plasma catecholamines. In Protocol 2, a 6-month randomized controlled trial using a subtherapeutic dose of the alpha(1)-adrenergic receptor antagonist doxazosin (1 mg/day) versus placebo in 86 patients with essential hypertension was performed to determine whether the increase in ROS formation by MNC was independent of BP.

RESULTS

In Protocol 1, a significant relationship was observed between the following: trait anxiety and plasma norepinephrine (r = 0.32, P < .01); plasma norepinephrine and ROS formation by MNC (r = 0.36, P < .01); and plasma norepinephrine and systolic, diastolic, and mean BP (r = 0.17, P = .04; r = 0.26, P = .02; r = 0.23, P < .01, respectively). In Protocol 2, subtherapeutic doxazosin treatment (1 mg/day) had no significant effect on BP. However doxazosin significantly decreased ROS formation by MNC compared with placebo (P < .01).

CONCLUSION

Trait anxiety may increase plasma norepinephrine and increase ROS formation by MNC independent of BP in hypertensive patients.