A double-blind trial on the effect of bunazosin hydrochloride for the symptoms of benign prostatic hypertrophy]

A multicenter clinical trial was carried out on 372 patients in double-blind conditions in order to determine the clinical effects of Ea-0643 (bunazosin hydrochloride) on voiding disorders in benign prostatic hypertrophy, compared with paraprost and placebo. Of the 372 patients, 129 were assigned to bunazosin hydrochloride, 118 to paraprost and 125 to placebo. The improvement rating for all five subjective symptoms improved with passage of time in all the bunazosin hydrochloride, paraprost and placebo groups. A higher improvement rating was obtained in the bunazosin hydrochloride group for retarded urination, urinary stream condition and abdominal pressure at voiding, while the improvement rating was higher for prolonged urination in the placebo group and for residual urine in the paraprost group, but there was no significant difference in improvement ratings between the groups. The daily frequency of voiding decreased to a significant extent in the bunazosin hydrochloride and placebo group at week 1, and there was a significant difference between the bunazosin hydrochloride and the paraprost groups and between the placebo and the paraprost groups. The improvement rating for conditions of voiding was higher with the bunazosin hydrochloride group, when "slightly or better improved" cases were taken into account, but there was no difference between the groups. As for objective symptoms, maximum and average flow rate, useful measures for clinical evaluation of drug effects on voiding disorders, were significantly increased, with a decrease to match in residual urine ratio in the bunazosin hydrochloride group. In terms of maximum and average flow rate bunazosin hydrochloride was significantly superior to paraprost at weeks 1 and 2 and superior to placebo at weeks 2 and 4 and at the final evaluation as well. In terms of residual urine ratio bunazosin hydrochloride was superior to both paraprost and placebo. The global improvement rating, as assessed by the U- and chi 2-tests, was significantly higher in the bunazosin hydrochloride group than in the paraprost group, and there was a significant difference in global improvement ratings, as assessed by the chi 2-test, between the placebo and the paraprost groups, when "moderately or better improved" cases were taken into account. The stratified analysis of the prostate glands, subjective symptoms, maximum flow rate and residual urine ratio revealed that in patients with more advanced conditions the bunazosin hydrochloride group showed significantly superior improvement rates than the paraprost and placebo groups.(ABSTRACT TRUNCATED AT 400 WORDS)     

A double-blind trial on the effect of alpha-adrenergic blocker (bunazosin hydrochloride) in the symptomatic treatment of prostatism

A double-blind placebo-controlled study of bunazosin for the treatment of symptomatic prostatism is reported, incorporating urologic departments of 25 hospitals. Four different doses of bunazosin hydrochloride was administrated orally to 174 patients having benign prostatic hyperplasia and 31 with bladder neck contracture for a period of four weeks; high dose group (45 patients, 3 mg/day for the first week followed by 4.5 mg/day for the next three weeks), middle dose group (45 patients, from 1.5 mg/day for the first week to 3.0 mg/day for the next three), low dose group (39 patient, 0.15 mg/day for the first to 1.5 mg/day for the next three) and a control group (40 patients, 0.125 mg/day for the entire four weeks). Subjective symptoms (urinary frequency, retarded urination, prolonged urination, condition of urinary stream and abdominal pressure at voiding) and objective signs (residual ratio, maximum and mean flow rate, voiding time) were observed and analyzed statistically. No bias in the background features was confirmed between any of the four groups. The subjective improvement rates evaluated by the attending doctors demonstrated a significant dose-dependent efficacy of bunazosin by H-test (p less than 0.01), although the objective improvement rates revealed no significant difference between any of the four groups. The global improvement rate evaluated by the same means demonstrated that the middle dose group was significantly superior to the control group (p less than 0.05 by U-test). According to each subjective symptom evaluated by the criteria of the drug efficacy, a dose-dependent significant (p less than 0.01) was noticed between the four groups in the improvement of the voiding condition. Although there was no significant difference by use of the H-test, the middle dose group had a significant superiority to the control group in the improvement rate of retarded voiding by use of the U-test (p less than 0.05). Only in the symptomatic cases of prolonged voiding, were dose-dependent significant differences observed between all four groups by use of the H-test (p less than 0.05). On the other hand, there was no significant difference between the four groups in the subjective or global improvement rates. Judging from the real data and the graded classification of objective signs, the high and middle dose groups were significantly superior to the control in terms of voiding time, and the high and low dose groups were the same as the control for residual urine ratio.(ABSTRACT TRUNCATED AT 400 WORDS)     

Clinical efficacy of oxendolene (antiandrogen) and bunazosin hydrochloride (alpha-adrenergic blocker) in the treatment of prostatism--comparative study of oxendolone, bunazocin hydrochloride and their combination

Antiandrogen and alpha-adrenergic blockers have recently been tried in the medical treatment for benign prostatic hypertrophy and bladder neck contracture. We herein report our results of a randomized comparative study on the clinical efficacy of oxendolone, bunazosin hydrochloride (bunazosin) and their combination for the treatment of benign prostatic hypertrophy and bladder neck contracture. The attending doctors evaluated at twelve weeks the improvement rate for three treatment regimens, 400 mg/day oxendolone, 3 mg/day bunazosin and a combination of both. Oxendolone + bunazosin showed the highest improvement rate in the evaluation of each subjective symptom and objective finding and of both. Oxendolone + bunazosin tended to show a better clinical efficacy than the other of these regimens, when the improvement was defined as that with more than one degree in the severity of retarded voiding, prolonged voiding, urinary stream condition, abdominal pressure on voiding and residual urine sensation. The improvement of such subjective symptoms seemed to occur earlier with oxendolone + bunazosin or bunazosin than with oxendolone. A significant difference was shown among the three treatment regimens in the general improvement rate on four subjective symptoms, with oxendolone + bunazosin being the highest followed by bunazosin and oxendolone in this order. The improvement rates of maximum and mean flow rate which are most important parameters to evaluate the voiding condition, at twelve weeks were significantly higher with oxendolone + bunazosin. No serious side effects were observed in this study, although treatment regimens containing bunazosin caused some minor side effects. These side effects could be prevented by the use of initial low doses of bunazosin with a subsequent gradual increment up to 3 mg/day. Taking the differences in the mechanism of oxendolone and bunazosin and the results of our study into consideration, we believe that the combination of oxendolone and bunazosin would be more useful in a clinical situation.     

The effect of moxisylyte hydrochloride in the symptomatic treatment of benign prostatic hyperplasia

The clinical effectiveness of moxisylyte hydrochloride (Moxyl, Fuji Rebio), a selective alpha 1-adrenoceptor blocking agent, was investigated in patients with symptomatic benign prostatic hyperplasia. Moxisylyte hydrochloride was administered at the dose of 90 mg per day orally for four weeks. Residual urine sensation was improved in 9 out of 17 cases (53%), retarded urination in 14 out of 19 (74%), prolonged urination in 12 out of 19 (63%), weak stream in 14 out of 21 (67%) and strained voiding in 11 out of 19 cases (58%). Residual urine volume and residual urine ratio were decreased in 14 out of 21 cases (67%), maximum urine flow rate was increased in 14 out of 21 (67%) and mean flow rate was increased in 15 out of 21 cases (71%). There was, however, no statistical significance between pre- and post drug administration in objective parameters. Our open trial showed that the subjective efficacy of moxisylyte hydrochloride was 82% (18/22 cases), the objective one was 59% (13/22 cases) and overall efficacy was 77%. Side effects were observed in four of all subjects (18.2%), and drug administration had to be ceased in only one of these patients due to mild dizziness. Other side effects were mild nausea, headache and chest discomfort. Decrease in blood pressure was not seen in all but one case.     

Clinical evaluation of supplemental administration of flavoxate hydrochloride in benign prostatic hyperplasia patients with nocturia resistant to an alpha1-adrenoceptor blocker

We examined the effectiveness of supplemental administration of flavoxate hydrochloride in patients with benign prostatic hyperplasia (BPH) whose nocturia was not adequately relieved by an alpha1-adrenoceptor blocker. Fifty-two patients who had two or more nocturnal micturition after administration of tamsulosin hydrochloride or naftopidil for 4 weeks or more received 400-600 mg of flavoxate hydrochloride in addition to an alpha1-adrenoceptor blocker for another 8-12 weeks. With supplemental administration of flavoxate hydrochloride, significant improvement was observed in the number of nocturnal micturition, total International Prostate Sympton Score, quality of life score and BPH impact index. No significant change was observed in the voided volume, Qmax, voiding time and residual urine volume. Supplemental administration of flavoxate hydrochloride is therefore effective for the improvement of nocturia and QOL in BPH patients resistant to an alpha1-adrenoceptor blocker.     

A randomized controlled study comparing clinical effects of naftopidil and tamsulosin on benign prostatic hyperplasia

A prospective randomized controlled study was performed to compare the clinical effects of naftopidil and tamsulosin. Men complaining of lower urinary tract symptoms due to benign prostatic hyperplasia were randomized into two groups : one receiving 50mg naftopidil once daily (Naf group, n=36 patients), and the other receiving 0.2 mg tamsulosin once daily (Tam group, n=32 patients). In the Naf group at 12 weeks, 7 items of the International Prostate Symptom Score (IPSS), storage and voiding symptoms, total IPSS, quality of life (QOL) index (QOLI) and Qmax were improved significantly. In the Tam group at 12 weeks, 6 items of IPSS except urgency, storage and voiding symptoms, total IPSS, QOLI and Qmax were improved significantly. Improvement of residual urine volume (PVR) was insignificant in both groups. In intergroup comparison between the Naf and the Tam groups, variations of 7 items of IPSS, storage and voiding symptoms, total IPSS, QOLI, Qmax and PVR at 4 and 12 weeks after treatment were not statistically significant. There was almost no difference in clinical efficacy between Naf and Tam.     

Usefulness and safety of bunazosin hydrochloride in neurogenic bladder after prolonged administration]

Bunazosin hydrochloride (Ea-0643), a selective alpha 1-blocker, was administered to 14 patients with neurogenic bladder over prolonged periods of time in order to determine its efficacy and safety. Subjective symptoms were classified into 4 grades, and their response assessed after 12 weeks of treatment. The proportion of patients showing improvement by at least one grade was 50.0% for retarded urination, 16.7% for prolonged urination, 25.0% for urinary stream condition, 25.0% for abdominal pressure at voiding, and 28.6% for residual urine. Objective symptoms were also assessed after 12 weeks of treatment, and a statistically significant improvement was recognized in the volume of spontaneously voided urine, the maximum and mean flow rates on uroflowmetry. It should be noted that both of those flow rates had improved significantly only 2 weeks into the treatment. The degree of improvement in subjective and objective symptoms and the degree of general improvement were all higher at week 12 than at week 2 of treatment. Current knowledge of the mechanism of action of this drug, coupled with the observations made in this study, suggests that, once it has improved the urodynamics, it exhibits a sustained effect for prolonged periods of treatment. However, further studies are warranted concerning the mechanisms of the pharmacological action of the drug from a pathological viewpoint. The proportion of patients in whom Ea-0643 was judged to be useful at 12 weeks of treatment was 41.7%, but when the assessment of 'slightly useful' was taken into consideration, the usefulness rate rose as high as 91.7%. Stomatitis was observed in only one case as a side effect of this drug.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical evaluation of the effect of tamsulosin hydrochloride and cernitin pollen extract on urinary disturbance associated with benign prostatic hyperplasia in a multicentered study

We evaluated the clinical efficacy and safety of tamsulosin hydrochloride and cernitin pollen extract in 243 patients with urinary disturbance associated with benign prostatic hyperplasia. They were assigned randomly to 3 groups, oral tamsulosin hydrochloride, cernitin pollen extract and their combination were administered for 12 weeks. The international prostate symptom score, post-voided residual urine and uroflowmetrogram were obtained before and after treatment. The international prostate symptom score improved in each group and then the maximum flow rate and average flow rate also increased significantly in the tamsulosin hydrochloride-administered groups. In conclusion, the administration of only tamsulosin hydrochloride and the combination of tamsulosin hydrochloride and cernitin pollen extract seemed more effective then the administration of only cernitin pollen extract in the treatment of urinary disturbance associated with benign prostatic hyperplasia.     

Local microwave hyperthermia of benign prostatic hyperplasia.

Recently, hyperthermia has been used for treatment of benign prostatic hyperplasia. The preliminary results reported were promising. However, apart from patients with total urinary retention, objective voiding parameters have not been reported in detail for patients with prostatism. In a phase II study we treated 30 patients with benign prostatic hyperplasia by local microwave hyperthermia (915 MHz.). The prostate was heated transrectally to 42 to 43C, with the treatment consisting of 8 sessions of 60 minutes each given twice a week. To assess the results of treatment several parameters were determined before and 4 weeks after hyperthermia therapy, including transrectal ultrasound of the prostate with volumetry, urinary flow rate and residual volume. Of the patients 28 could be evaluated and only 2 showed a relevant improvement. Neither the voiding parameters nor the size of the prostate could be changed significantly by hyperthermia. The success rate of 7.1% is even lower than the spontaneous temporary regression rate of benign prostatic hyperplasia. Thus, we believe that hyperthermia cannot be regarded as an effective treatment for benign prostatic hyperplasia comparable to transurethral resection.     

Silodosin versus naftopidil for the treatment of benign prostatic hyperplasia: A multicenter randomized trial

This was a multicenter randomized trial to investigate the clinical efficacy and the impact on sexual function of alpha‐1A selective silodosin and alpha‐1D selective naftopidil for treatment of benign prostatic hyperplasia. A total of 97 patients with lower urinary tract symptoms/benign prostatic hyperplasia who had an International Prostate Symptom Score of 8 or more were randomly assigned to receive silodosin (8 mg/day, n = 53) or naftopidil (75 mg/day, n = 44). Before and 4, 8 and 12 weeks after treatment, International Prostate Symptom Score and its quality of life score were used to assess lower urinary tract symptoms. Also, International Index of Erectile Function‐5, and an original questionnaire were used to evaluate erectile function and ejaculation for sexually active patients, respectively. The silodosin group showed advantages in terms of voiding symptoms and quality of life of International Prostate Symptom Score when compared with the naftopidil group. Both silodosin and naftopidil showed no significant effect on International Index of Erectile Function‐5. A total of 23 sexually active patients in the silodosin group experienced more ejaculatory impairment than 21 patients in the naftopidil group, with a decrease of ejaculation volume (87% vs 40%, P = 0.003), prolonged time to ejaculation (56% vs 33%, P = 0.027) and decrease of orgasm (50% vs 39%, P = 0.027). These results suggest that alpha‐1A selective blockers are more effective for voiding symptoms, whereas alpha‐1D selective blockers offer a minor degree of ejaculatory dysfunction.     

A case of infravesical obstruction caused by prostatic stones as diagnosed by transrectal ultrasonography at voiding]

A 69-year-old patient, who had been treated using alpha 1-blocker for benign prostatic hyperplasia (BPH) at another clinic, visited our clinic due to persistent difficulty in urination. Total International Prostate Symptom Score (IPSS) was 32 points and quality of life (QOL) index was 5. Uroflowmetry demonstrated maximum urinary flow rate and average urinary flow rate to be 9.2 ml/sec and 5.1 ml/sec, respectively, with 3 ml of residual urine volume. Transrectal ultrasonography (TRUS) revealed prostatic stones but not BPH. Retrograde urethrography demonstrated nothing abnormal other than prostatic stones. TRUS at voiding phase using linear probe (voiding TRUS) revealed poor opening of the urethra surrounded by prostatic stones. As a result, the cause of urinary disturbance was diagnosed to be due to urethral obstruction caused by prostatic stones, and transurethral resection of prostatic tissue with stones was performed. Postoperatively, IPSS decreased to 10 points and QOL index to 2. Maximum urinary flow rate also improved to 18.1 ml/sec and mean urinary flow to 8.4 ml/sec. Thus, voiding TRUS is likely the best urodynamic test for clinical use in determining the etiology of obstruction at posterior urethra.     

Kampo preparations for prostatic hyperplasia: usefulness of Saireito for nocturia

Prostatic hyperplasia is characterized by major voiding symptoms, and treatment aims principally at improving the quality of life. Nocturnal frequency is a primary symptom that markedly impairs the quality of life. In addition to alpha 1-receptor blockers and antiandrogen agents, herbal medicines and kampo preparations have also been used, but they have not always proved satisfactory. In this study, we investigated the effect of a diuretic kampo preparation (Kanebo Saireito Extract Fine Granules) on urine output, and evaluated the efficacy of Saireito (5.4 g/day, bid) in 12 patients (mean age, about 68) with prostatic hyperplasia who had completed basic therapy but still complained of nocturnal frequency. The following results were obtained. 1) Saireito caused a significant increase of daytime urine output and significantly reduced nocturnal output. 2) It significantly reduced the nocturnal frequency, although that of daytime urination remained unchanged. 3) The drug significantly improved symptoms that existed before treatment. These results suggest that Saireito is effective for nocturia in patients with prostatic hyperplasia.     

Comparison of tamsulosin and naftopidil for efficacy and safety in the treatment of benign prostatic hyperplasia: a randomized controlled trial

OBJECTIVES: To compare the efficacy and safety of two alpha1a/alpha1d adrenoceptor (AR) antagonists with different affinity for the alpha1AR subtypes, tamsulosin and naftopidil, in the treatment of benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: Patients with BPH were randomized to receive either tamsulosin or naftopidil. The primary efficacy variables were the changes in the total International Prostate Symptom Score (IPSS), maximum flow rate on free uroflowmetry, and residual urine volume. The secondary efficacy variables were average flow rate, changes in the IPSS storage score, IPSS voiding score, and quality-of-life (QoL) Index score, from baseline to endpoint (12 weeks). Data on all randomized patients were included in the safety analyses for adverse effects and changes in blood pressure. RESULTS: Of the 185 patients enrolled data for 144 who were eligible for inclusion in the efficacy analysis were analysed (75 from the tamsulosin and 69 from the naftopidil group). There was no significant difference in any variable at baseline between the groups. There were statistically significant improvements for all primary and secondary variables in both groups, except for residual urine in the tamsulosin group. However, there was no significant intergroup difference in the improvement of any efficacy variable between the groups. The adverse effects were comparable, with no significant differences in systolic and diastolic blood pressure after treatment in both groups. CONCLUSIONS: This study suggests that naftopidil is as effective and safe as tamsulosin. Both drugs were effective in improving storage and voiding symptoms. However, there was no difference in clinical efficacy or adverse effects between the alpha1 AR antagonists with different affinity to alpha1 subtypes, alpha1a and alpha1d.     

Clinical evaluation of balloon dilatation in patients with benign prostatic hyperplasia]

Balloon dilatation of the urethra was performed on 38 patients (aged 61 to 89 years) with benign prostatic hyperplasia. Of the 38 patients, 34 (89.5%) achieved improvement of symptoms including urinary retention and difficulty on urination and no recurrence of symptoms was observed during a follow-up period. The maximum flow rate remarkably increased after the treatment in the patients and there was no increase of residual urine volume in 17 patients followed up for 6 to 12 months. The balloon dilatation of the prostatic urethra proved to be useful for patients with benign prostatic hyperplasia.     

Efficacy and side-effects of prazosin as a symptomatic treatment of benign prostatic obstruction.

This randomized double-blind crossover trial was conducted to assess the effects of prazosin, an alpha 1-adrenoceptor blocking drug, on the voiding of 35 patients with benign prostatic obstruction. Maximum and mean flow rates, residual urine, blood pressure and heart rate were measured at baseline and 2, 4, 6, and 8 weeks after starting the treatment with placebo or prazosin. At 4 weeks the treatments were switched over. The patients filled micturition charts at home and scored their voiding associated feelings. The maximum and mean flow rates increased significantly during prazosin treatment, as also did the maximum and mean voided volumes. Residual urine decreased and voiding improved subjectively but these changes were not statistically significant. Blood pressure was lowered and heart rate increased. Prazosin caused postural dizziness more often than placebo. Prazosin seems to offer an alternative to improve voiding in some patients with prostatic obstruction.     

Treatment of benign prostatic hyperplasia by androgen deprivation: effects on prostate size and urodynamic parameters

The possible effect of medical androgen deprivation in the treatment of benign prostatic hyperplasia has been studied in 12 patients. Six patients received the luteinizing hormone-releasing hormone agonist buserelin and 6 others received the antiandrogen cyproterone acetate. The treatment resulted in an average decrease in prostatic size of 29 per cent after 12 weeks as measured by ultrasonography. This decrease led to an increase in peak urinary flow rate, a reduction in residual urine volume and a decrease in daytime voiding frequency. However, it caused no decrease in urethral resistance but only an increase in the bladder contraction strength. After discontinuation of the treatment the prostates showed regrowth to the initial sizes within 6 to 36 weeks. The urodynamic changes were reversed as well. Although statistically significant, the urodynamic changes were minimal from a clinical viewpoint and did not lead to an unobstructed state after 12 weeks of treatment. For this reason the clinical indication for use of medical androgen deprivation in benign prostatic hyperplasia patients will remain limited for the time being.     

Postoperative Voiding Dysfunction in Older Male Renal Transplant Recipients

Objective

To evaluate the incidence of voiding dysfunction in older male renal transplant recipients.

Patients and Methods

Data for 103 patients aged 60 years or older (mean age, 65.7 years; group 1) who underwent transplantation at our center between January 1999 and August 2007 were compared with data for a group of 139 younger patients (mean age, 50.1 years; group 2) treated within the same time frame.

Results

Postoperatively, 28 group 1 recipients (27%) and 26 group 2 recipients (19%) experienced voiding dysfunction after removal of the transurethral catheter (P = .12). The most common cause was bladder outlet obstruction due to benign prostatic hyperplasia in 26 patients in group 1 (25%) and 17 patients in group 2 (12%) (P = .009). Bladder neck contracture, urethral stricture, and detrusor underactivity were diagnosed in the other patients. Transurethral resection of the prostate gland was performed in 21 group 1 patients (20%) and 14 group 2 patients (10%) (P = .02) at a mean of 31.1 and 29.5 days, respectively (P = .23) after transplantation. Surgical procedures were performed without complication, and symptoms did not recur postoperatively.

Conclusions

Our data reveal a high incidence of voiding dysfunction in older male renal transplant recipients. High residual urine and urinary retention after renal transplantation may induce recurrent urinary tract infections, cause relevant complications, and seriously affect graft function. Recognizing the substantial effects of postoperative voiding dysfunction will enable optimum management of older kidney transplant recipients.     

老年前列腺增生患者睾丸切除姑息术后拔尿管时机的研究

目的 探讨老年前列腺增生患者睾丸切除术后拔除尿管的适宜时机.方法 将96例睾丸切除术后留置尿管的前列腺增生患者按入院时间分为三组各32例,A组患者术后2～3 d或有尿路不适即拔除尿管,B组术后7 d拔除尿管,C组术后14 d拔除尿管,观察患者排尿情况.结果 A、B、C组患者拔除尿管后排尿成功率分别为15.62%、40....     

Transurethral Balloon Laser Thermotherapy for Urinary Retention in Patients with Benign Prostatic Hyperplasia Who Are at High Surgical Risk

Background Twelve patients with benign prostatic hyperplasia and urinary retention, who were considered to be poor candidates for prostatectomy, were treated by transurethral balloon laser thermotherapy (TUBAL-T). The mean patient age was 78.9 years (range, 66 to 93 years) and the mean duration of bladder catheterization was 11 weeks (range, 2 to 48 weeks).
Methods Irradiation into the prostatic tissue was done through 360 with a neodymium: yttrium aluminum garnet (Nd:YAG) laser balloon placed in the prostatic urethra, with pain relief provided by using local topical anesthesia. The total laser dose was from 45,000 to 1 23,376 J, with an average of 73,089 J. The irradiation time was from 40 to 54 minutes, with an average of 45.2 minutes.
Results Spontaneous voiding became possible in all patients at a mean of 2.8 days (range, 1 to 7 days) after irradiation. The mean catheter-free period was 20.5 months (range, 6 to 34 months), with the longest being 34 months. The international prostatic symptom scores, quality-of-life scores, and peak uroflow rates showed substantial improvement after laser thermotherapy. To date, long-term resumption of spontaneous voiding was successfully achieved in 9 of 12 cases (75%).
Conclusion TUBAL-T is a safe and effective alternative for treatment of urinary retention in patients with benign prostatic hyperplasia who are considered to be at high surgical risk.     

A 12-week placebo-controlled double-blind study of prazosin in the treatment of prostatic obstruction due to benign prostatic hyperplasia.

A series of 93 normotensive patients with benign prostatic hyperplasia and maximum urinary flow rates < 15 ml/s, treated at 2 hospital centres using an identical protocol, was randomly assigned to receive a 12-week course of treatment with prazosin or placebo in a double-blind parallel group trial. A total of 75 patients completed the study and were suitable for the final analysis. Prazosin was administered orally in doses of 0.5 mg and then 1 mg twice daily for 4 days and 2 mg twice daily for the remainder of the trial. Patients on treatment with prazosin exhibited a significantly increased maximum urinary flow rate as compared with placebo, with a significant reduction in maximum voiding detrusor pressure. Prazosin therapy did not produce a significant effect on either frequency or standard parameters of detrusor instability. A double-blind overall assessment of drug efficacy and tolerance significantly favoured prazosin therapy. A total of 30 patients receiving prazosin and 28 receiving placebo reported varied adverse effects. Eighteen patients were excluded from the final analysis, 10 being withdrawn because of adverse effects, 7 on treatment with prazosin and 3 in the placebo group. In long-term usage oral prazosin was well tolerated and appeared to improve obstructed voiding in patients with benign prostatic hyperplasia.