Alfuzosin, an alpha1-adrenoceptor antagonist for the treatment of benign prostatic hyperplasia: once daily versus 3 times daily dosing in healthy subjects

Pharmacokinetics and Bioequivalence Estimation of Two Formulations of Alfuzosin Extended-Release Tablets

Alfuzosin is a medication approved by the US Food and Drug Administration to treat benign prostatic hyperplasia symptoms. Bioequivalence studies are demanded by regulatory authorities to evaluate the expected in vivo biological similarity of 2 formulations of a medication. The aim of this study is to assess the bioavailability of the generic (test) and branded (reference) formulations of 10-mg alfuzosin extended-release tablets after oral administration to healthy adults under fed conditions. The study used a comparative randomized, single-dose, 2-way crossover open-label study design. Thirty-three participants were recruited and completed the clinical assessment. The pharmacokinetic parameters maximum plasma concentration (C_max ), area under the plasma concentration-time curve (AUC_0-t ), AUC extrapolated to infinity (AUC_0-∞ ), time to maximum concentration, and elimination half-life were estimated to prove bioequivalence. The confidence intervals for the log-transformed test/reference ratios for alfuzosin 110.7% (98.0-124.9) and 112.0% (101.9-123.1) for C_max and AUC_0-t respectively, which are within the allowed limits specified by the regulatory authorities (80-125% for C_max and AUC_0-t ). The test formulation can therefore be prescribed as an alternative to the reference for symptomatic treatment of benign prostatic hyperplasia.

Effects of alfuzosin 10 mg once daily on sexual function in men treated for symptomatic benign prostatic hyperplasia

We evaluated the effects of extended-release alfuzosin HCl 10 mg once daily (q.d.) on sexual function in men with lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH). In a randomized, double-blind, placebo-controlled study of men aged > or = 50 years, after a 28-day placebo run-in period, patients were randomized to receive alfuzosin 10 mg q.d. or matching placebo for 28 days. The mean change from baseline (day 1) in sexual function on day 29 was assessed using the Danish Prostate Symptom Score Sex (DAN-PSSsex) questionnaire. A total of 372 patients were randomized to receive alfuzosin (n=186) or placebo (n=186), with 355 completing the study. At baseline, 64% of the patients reported erectile dysfunction (ED) and 63% reported ejaculatory dysfunction (EjD). For the 320 patients who completed the DAN-PSSsex, alfuzosin treatment was associated with a significant improvement in the mean change from baseline in erectile function on day 29 compared with placebo (P=0.02). No significant difference was observed between the two treatment groups in the mean change from baseline in ejaculatory function on day 29. For patients with ED at baseline, a marginal improvement in erectile function was demonstrated with alfuzosin treatment (P=0.09 vs placebo). For patients with EjD at baseline, the mean change from baseline in ejaculatory function with alfuzosin was comparable to that with placebo. Dizziness was the most common adverse event with alfuzosin treatment (5 vs 0% with placebo), with other adverse events reported with comparable frequency in both treatment groups. After 1 month of treatment, alfuzosin 10 mg q.d. significantly improved erectile function in men with lower urinary tract symptoms/ benign prostatic hypertrophy and had no adverse effect on ejaculatory function.

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.

Age, Comorbidity and Hypertensive Co-Medication do Not Affect Cardiovascular Tolerability of 10 Mg Alfuzosin Once Daily

PURPOSE

We assessed in real-life practice the impact of age, cardiovascular comorbidity and co-medication on the tolerability and efficacy of 10 mg alfuzosin OD in men with lower urinary tract symptoms suggestive of benign prostatic obstruction.

MATERIALS AND METHODS

A total of 6,523 men with a mean age of 64.7 years were enrolled in a 6-month open label study of 10 mg alfuzosin OD. They were stratified by age quartile (younger than 60, 60 to 64, 65 to 70 and older than 70 years), comorbidity (hypertension, ischemic heart disease and diabetes) and antihypertensive co-medication (diuretics, beta-blockers, angiotensin converting enzyme inhibitors, angiotensin II inhibitors and calcium channel antagonists).

RESULTS

Alfuzosin was effective and well tolerated. Despite an increased prevalence of cardiovascular comorbidity and antihypertensive co-medication with age changes in blood pressure did not significantly differ among age groups. In controls, ie those with no cardiovascular comorbidity or co-medication, alfuzosin produced minimal decreases in sitting systolic (mean -2.6 to -2.8 mm Hg) and diastolic (mean -1.7 to -1.8 mm Hg) blood pressure. In men with cardiovascular comorbidity mean decreases in systolic (-3.5 to 5.8 mm Hg) and diastolic (-2.0 to -3.3 mm Hg) blood pressure remained marginal. Of the 6,523 exposed patients 19.3% withdrew from the study, mainly for adverse events (6.4%) or a lack of efficacy (5.3%), while 229 (3.5%) experienced serious adverse events and 1,558 (23.9%) reported at least 1 treatment emergent adverse event. The most commonly reported adverse event was dizziness/postural dizziness (4.8%). Hypotension/postural hypotension was uncommon (0.7%). Age, cardiovascular comorbidity and antihypertensive co-medication had no impact on the safety profile of 10 mg alfuzosin OD.

CONCLUSIONS

Alfuzosin (10 mg) OD is effective and well tolerated, and it has marginal effects on blood pressure, including in elderly patients and those with hypertension, ischemic heart disease or diabetes and those receiving antihypertensive agents.

Efficacy and safety of two doses (10 and 15 mg) of alfuzosin or tamsulosin (0.4 mg) once daily for treating symptomatic benign prostatic hyperplasia

OBJECTIVE

To evaluate the efficacy and safety of two doses (10 and 15 mg) of alfuzosin once daily and tamsulosin (0.4 mg) once daily, compared with placebo, in men with benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

In this randomized, double-blind, placebo-controlled, multicentre study, 625 patients were randomized to receive alfuzosin 10 or 15 mg once daily, tamsulosin 0.4 mg once daily (active reference), or matching placebo for 12 weeks, with no initial dose titration. The study was designed to compare each of the three active treatments with the placebo group. Primary outcome measures were mean changes from baseline in the International Prostate Symptom Score (IPSS) and peak urinary flow rate (Qmax) at 12 weeks, compared with placebo, using one-way analysis of variance. Because Qmax data were not normally distributed, median changes from baseline were also compared for Qmax. Pair-wise comparisons were conducted using the Dunnett correction for quantitative variables and Bonferroni-Holm correction for categorical variables, allowing for multiple treatment group comparisons.

RESULTS

Alfuzosin 10 mg significantly improved urinary tract symptoms compared with placebo, with a mean (sd) change from baseline in the IPSS of -6.5 (5.2) vs -4.6 (5.8) for placebo (adjusted P = 0.007); there was a trend toward a difference between alfuzosin 15 mg, with a mean (sd) change from baseline in IPSS of -6.0 (5.6), and placebo (adjusted P = 0.050). The mean change from baseline in IPSS with tamsulosin 0.4 mg, at -6.5 (5.6), vs placebo was also significant (adjusted P = 0.014). The median change from baseline in Qmax was significantly increased with both alfuzosin doses and with tamsulosin (all adjusted P = 0.02 vs placebo). Both doses of alfuzosin were well tolerated, with dizziness the most frequent adverse event (placebo, 4%; alfuzosin 10 mg, 6%; 15 mg, 7%; tamsulosin, 2%); the respective incidence rates of sexual function adverse events were 0%, 3%, 1% and 8%.

CONCLUSION

Treatment with alfuzosin 10 mg significantly improved urinary symptoms and Qmax compared with placebo and was well tolerated. There were also significant improvements over placebo with the active reference, tamsulosin 0.4 mg. The incidence of sexual function adverse events was higher with tamsulosin than with placebo. The benefit-to-risk profile of alfuzosin 10 mg once daily appeared to be reduced with a higher dose (15 mg).

Alfuzosin for the management of benign prostate hyperplasia

Alfuzosin (UroXatral, Sanofi-Synthelabo) a quinazoline derivative, has well-documented alpha(1)-adrenoreceptor antagonist activity. These receptors are present in the smooth muscle located at the bladder base, proximal urethra, prostate and prostatic capsule as well as in vascular and nervous systems. Consequently, alfuzosin has the ability to reduce the tone of these areas, effectively decreasing bladder outlet resistance. A sustained-release formulation of alfuzosin is currently available in Europe and is FDA-approved in the US. The confirmed efficacy, proven bioavailability and good cardiovascular safety profile support the use of this drug for the management of lower urinary tract symptoms secondary to benign prostate hyperplasia (BPH). These findings have been confirmed in a large cohort of patients treated in general practice. Additionally, treatment with alfuzosin has demonstrated a favourable impact on quality of life of patients with BPH.

Effect of Once-Daily Alfuzosin on Urinary Symptoms and Flow Rate in??Benign Prostatic Hyperplasia

OBJECTIVE

To analyse the clinical and 24-hour urinary flow efficacy of alfuzosin 10mg once daily (OD), by means of the International Prostate Symptom Score (I-PSS) and home-based uroflowmetry (P-Flow) measurement, in patients with lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia.

MATERIALS AND METHODS

In this open-label trial, 12 male patients (median age 67 years) with an I-PSS >15 (median 16) and maximum urinary flow (Q(max)) <15 mL/sec were evaluated. Patients underwent two days of P-Flow evaluation, and then received alfuzosin 10mg OD from day 3 to day 9. On days 7 and 8 they underwent further P-Flow evaluation. A second post-baseline evaluation I-PSS was recorded on day 9.

RESULTS

Overall, 328 urinary flows were recorded and evaluated, an average of 27 flows per patient. A statistically significant improvement in mean maximum flow: (Q(max)) [10.8 +/- 2.8 vs 12.4 +/- 3 mL/sec; p = 0.02] and urinary voiding volume (219 +/- 70 vs 233 +/- 55mL; p = 0.04) were observed after treatment compared with baseline. No differences in the number of urinary flows were observed between baseline and after treatment (13 +/- 2.9 vs 14 +/- 1.8 flows; p = 0.199). A statistically significant difference between the two evaluations was noted for I-PSS (15.7 +/- 0.8 and 9.5 +/- 2; p = 0.02). Mean Q(max) recorded during treatment was always higher than baseline at different daytime evaluations.

CONCLUSION

The alfuzosin 10mg OD formulation showed a significant improvement in I-PSS as well as a significant improvement in urinary flow parameters (Q(max)and urinary voiding volume) lasting for 24 hours in patients with LUTS.

Extended-release alfuzosin hydrochloride: A new alpha-adrenergic receptor antagonist for symptomatic benign prostatic hyperplasia

BACKGROUND

Extended-release (ER) alfuzosin hydrochloride is the most recently approved alpha-adrenergic receptor antagonist (AARA) for the management of symptomatic benign prostatic hyperplasia (BPH). Although new to the United States, alfuzosin has been available in immediate-release (IR) and sustained-release (SR) formulations in other countries for many years.

OBJECTIVE

This article reviews data on the pharmacodynamics, pharmacokinetics, efficacy, tolerability, drug-interaction potential, and dosing of alfuzosin ER.

METHODS

Relevant articles were identified through MEDLINE, EMBASE, and International Pharmaceutical Abstracts searches of the English-language literature published between 1986 and September 2003 using the terms alfuzosin, alpha-adrenergic receptor antagonists, and quinazolines. The reference lists of identified articles were also searched, as were abstracts from annual meetings of the American Urological Association for the past 5 years. Data regarding the ER formulation were emphasized, and data involving the IR/SR formulations were included only when data for the ER formulation were not available or as needed for clarification.

RESULTS

In comparative trials with its IR counterpart (alfuzosin ER 10 mg QD vs alfuzosin IR 2.5 mg TID), alfuzosin ER was an equieffective once-daily AARA. No comparative trials of alfuzosin ER with the SR (BID) formulation or with other AARAs were identified. Food has been found to exert a clinically important effect by enhancing the bioavailability of the ER formulation; thus, the drug should be taken on a full stomach. Hepatic impairment has been found to significantly delay the elimination of alfuzosin IF, which constitutes a contraindication to use of the ER formulation. Renal impairment does not appear to exert clinically important effects on the pharmacokinetics of alfuzosin ER. Adverse events with alfuzosin ER include dizziness, upper respiratory tract infection, headache, and fatigue, with hypotension and syncope reported rarely. Concurrent use of inhibitors of the cytochrome P450 3A4 isozyme (eg, ketoconazole, diltiazem, cimetidine, atenolol) can significantly elevate serum concentrations of alfuzosin and enhance its pharmacodynamic effects.

CONCLUSIONS

In the absence of direct head-to-head comparative trials, the role of alfuzosin ER in the management of symptomatic BPH relative to that of other AARAs is unclear. Because the effect size (drug response minus placebo response) of alfuzosin ER is comparable to that of other AARAs, marked differences in efficacy are unlikely. Extrapolating from direct comparative trials between these agents and alfuzosin IR/SR, alfuzosin ER would be expected to have better cardiovascular tolerability (eg, in terms of dizziness and orthostasis) than prazosin, terazosin, or doxazosin, and to have similar tolerability to tamsulosin. However, the existing data do not suggest that alfuzosin ER is likely to represent a significant advance over tamsulosin.

First dose efficacy of alfuzosin once daily in men with symptomatic benign prostatic hyperplasia

OBJECTIVES

To evaluate the onset of action of alfuzosin once daily (OD) as determined by uroflowmetry early after initial dosing. Alfuzosin OD is an extended-release formulation of a uroselective, alpha1-adrenoreceptor-blocking agent (alpha-blocker) used in the treatment of lower urinary tract symptoms due to benign prostatic hyperplasia.

METHODS

This was a randomized, placebo-controlled, two-way Latin square crossover study. Forty-nine patients were selected for this study on the basis of their symptomatic improvement during previous treatment with alpha-blockers and significant decreases in urinary flow rate when that treatment was withdrawn.

RESULTS

Our analysis showed that significant increases in the maximal urinary flow rate (Qmax) in 34 assessable patients occurred as soon as 8 hours after the initial dose of medication and persisted for at least 4 days. The DeltaQmax for alfuzosin 10 mg OD was 3.2 mL/s and for placebo it was 1.1 mL/s. The difference of means for the assessable population was 2.1 (95% confidence interval 0.8 to 3.4, P = 0.002). The overall incidence of adverse events was low. Only dizziness, experienced by 3 patients treated with alfuzosin compared with 1 patient treated with placebo, appeared to be related to the study drug.

CONCLUSIONS

Together, our findings suggest that alfuzosin OD exhibits a urodynamically measurable effect on bladder outlet obstruction due to benign prostatic hyperplasia in men with lower urinary tract symptoms within hours of the first administration.