Finasteride: a long-term follow-up in the treatment of recurrent hematuria associated with benign prostatic hyperplasia

Short-term pretreatment with a dual 5α-reductase inhibitor before bipolar transurethral resection of the prostate (B-TURP): evaluation of prostate vascularity and decreased surgical blood loss in large prostates

OBJECTIVE

To investigate if short-term treatment with dutasteride (8 weeks) before bipolar transurethral resection of the prostate (B-TURP) can reduce intraoperative bleeding, as dutasteride a dual 5α-reductase inhibitor (5-ARI) blocks the conversion of testosterone into its active form dihydrotestosterone (DHT), and reduces prostate volume and prostate-specific antigen (PSA) levels, while increasing urinary flow rate.

PATIENTS AND METHODS

In all, 259 patients were enrolled and randomised to two groups: Group A, receiving placebo and Group B, receiving dutasteride (0.5 mg daily for 8 weeks). Blood samples were taken before and after B-TURP for serum chemistry evaluation. In particular we evaluated blood parameters associated with blood loss [haemoglobin (Hb) and haematocrit (Ht)] and prostate vascularity [vascular endothelial growth factor (VEGF) immunoreactivity and microvessel density (MVD) using cluster of differentiation 34 (CD34) immunoreactivity].

RESULTS

Total testosterone, DHT, PSA level and prostate volume were evaluated and with the exception of DHT and PSA level there was no statistically significant differences between the groups. When comparing changes in Hb and Ht between Group A and Group B before and after B-TURP, there was a statistically significant difference only in patients with large prostates of ≥50 mL (ΔHb 3.86 vs 2.05 g/dL and ΔHt 4.98 vs 2.64%, in Groups A and B, respectively). There was no significant difference in MVD and VEGF index in prostates of <50 mL, conversely in large prostates the difference become statistically significant.

CONCLUSIONS

Dutasteride was able to reduce operative and perioperative bleeding only in patients with large prostates (≥50 mL) that underwent B-TURP. Our findings are confirmed by Hb and Ht values reported before and after the B-TURP and reductions in the molecular markers for VEGF and CD34 in the dutasteride-treated specimens.

Blood loss and postoperative complications associated with transurethral resection of the prostate after pretreatment with dutasteride

OBJECTIVE

To determine whether pretreatment with dutasteride, a dual 5alpha-reductase inhibitor (5ARI), reduces surgical blood loss or postoperative complications in patients with benign prostatic hyperplasia (BPH) who undergo transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

This double-blind, randomized, placebo-controlled, multicentre study comprised 214 patients with BPH. Placebo was compared with dutasteride 0.5 mg/day 2 weeks before and after TURP, or 4 weeks before and 2 weeks after TURP. Surgical blood loss was measured using a haemoglobin photometer (HemoCue AB, Angelholm, Sweden) and postoperative adverse events were recorded. Microvessel density (MVD) was calculated by immunostaining and light microscopy of the prostatic chips.

RESULTS

Although dutasteride reduced serum dihydrotestosterone (DHT) by 86-89% in 2-4 weeks, and intraprostatic DHT was approximately 10 times lower than in the placebo group, the (adjusted) mean haemoglobin (Hb) loss during surgery was 2.15-2.55 g Hb/g resectate with no significant difference in blood loss between the groups either during or after TURP. Clot retention occurred in 6-11% and urinary incontinence in 14-15% of patients during the 14 weeks after TURP, with no difference between the groups. The MVD at TURP was also similar for all groups.

CONCLUSION

There were no significant reductions in blood loss during or after TURP or complications afterward with dutasteride compared with placebo, despite significant suppression of intraprostatic DHT. Blood loss and transfusion rates in the placebo group were lower than those previously reported in studies where there was a beneficial effect of a 5ARI, relative to placebo, on bleeding during TURP.

Effect of androgen concentration on seminal vesicle blood flow in rats—establishment of new highly sensitive simultaneous androgen measurement method

OBJECTIVES

To clarify the effect of androgen concentration on blood flow regulation in seminal vesicles and to identify the androgen most responsible for this effect.

METHODS

The androgen concentrations in the seminal vesicles and the seminal vesicle blood flow were measured at 0, 3, 6, 12, 24, 48, and 72 hours after castration. The androgen concentration was measured with a newly developed highly sensitive simultaneous androgen quantification method that uses liquid chromatography-tandem mass spectrometry. The blood flow was measured with the radioactive microsphere injection method. The change in seminal vesicle blood flow in 6-hour castrated rats after administration of 3 mg/kg testosterone, 3 mg/kg dihydrotestosterone (DHT), 3 mg/kg dehydroepiandrosterone, or 3 mg/kg testosterone plus 20 mg/kg finasteride was evaluated.

RESULTS

A correlation was observed between the DHT concentration and blood flow in the rat seminal vesicle after castration. The DHT concentration and blood flow decreased after castration to 31.6% and 37.9%, respectively, of the normal level at 6 hours. The decline in DHT concentration and blood flow decreased further thereafter to 2.2% and 18.1%, respectively, of the normal level at 72 hours. Both testosterone and DHT fully restored the organ blood flow in castrated rat seminal vesicles. However, the blood-flow-increasing effect of testosterone was attenuated by more than 50% when administered in combination with finasteride. Dehydroepiandrosterone did not increase seminal vesicle blood flow.

CONCLUSIONS

The results of our study showed a strong correlation between the organ DHT concentration and blood flow in rat seminal vesicles. Of the various androgens, the most active androgen in the regulation of seminal vesicle blood flow was DHT.

Pharmacological therapy of benign prostatic hyperplasia/lower urinary tract symptoms: an overview for the practising clinician

Less than 10 years ago surgery and watchful-waiting were the only widely accepted management options for lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) and benign prostatic obstruction (BPO). There has been an enormous decline in the popularity of surgery and it is now apparent that medication is the most frequently used treatment for BPH/LUTS; this has arguably therefore been the most major change in urological clinical practice in the last decade. Currently alpha(1)-adrenoceptor antagonists are the commonest medical therapy, and are thought to act by relaxing prostatic smooth muscle, the neural or so-called 'dynamic' component of BPO. 5alpha-reductase inhibitors (finasteride, dutasteride) are another option for BPH/LUTS, which reduce prostatic mass and therefore the mechanical or 'static' component of BPO. In the last 10 years there have been four direct comparative studies between alpha(1)-adrenoceptor antagonists and finasteride, including their combination, the results of which, and their implications for therapy, are discussed. Another group of agents are the phytotherapeutic extracts, which act via various mechanisms, many as yet poorly defined. This review critically assesses existing publications relating to the medical management of BPH/LUTS.

Hormonal and morphologic evaluation of the effects of antiandrogens on the blood supply of the rat prostate

OBJECTIVES

To clarify the basic aspects of the regulation of the prostatic blood supply by antiandrogens, their effect on the prostatic blood supply was studied for both androgen content and morphology of true capillaries in the rat ventral prostate. The effectiveness of antiandrogens on the control of hemorrhagic status in prostatic diseases has been previously reported.

METHODS

Androgen concentrations in the prostate were quantified after administration of chlormadinone acetate (CMA), finasteride, or flutamide. The prostatic blood supplies were measured after administration of CMA, finasteride, flutamide, or bicalutamide. The alpha-blockers, terazosin and tamsulosin, were included in the study as negative controls. The histologic changes in the capillaries of the ventral prostate were observed, and the luminal area was measured.

RESULTS

The prostate dihydrotestosterone concentrations were decreased by the administration of all antiandrogens. Treatment with CMA, finasteride, flutamide, or bicalutamide reduced the prostatic blood supply by 50% to 65%. The parallel reduction in luminal areas of the true capillaries was observed in rats treated with CMA. Treatment with alpha-blockers did not affect the prostate androgen content, prostatic blood supply, or capillary luminal area.

CONCLUSIONS

The reduction of the prostatic blood supply was suggested to be the result of a decrease in dihydrotestosterone content and the reduction in the luminal area of capillaries. The early reductive effect of antiandrogens on the prostatic blood supply suggests an alternative use for antiandrogens independent of their typical use for prostate volume regression. The results support the basic aspects of the advantage of preoperative treatment with CMA, flutamide, and bicalutamide, similar to finasteride, in reducing perioperative hemorrhage.

5 alpha-reductase inhibitors: what's new?

PURPOSE OF REVIEW

Medical therapy is now the first-line treatment for most men with symptomatic benign prostatic hyperplasia. This review aims to highlight the recent contributions to our understanding of 5 alpha-reductase inhibitor usage.

RECENT FINDINGS

For the last decade, finasteride has been the only available 5 alpha-reductase inhibitor, acting upon the type 2 isoenzyme of 5-alpha reductase. Dutasteride is the first drug that can inhibit both isoenzymes and is soon to be available. Biochemically it achieves greater and more rapid dihydrotestosterone suppression compared with finasteride. Clinically, it appears to be at least as good in terms of improving symptoms and flow rates, and reducing the risk of acute urinary retention or the requirement for benign prostatic hyperplasia-related surgery. However, until these two drugs are formally compared, the true benefits of additional type 1 isoenzyme inhibition are unknown. The recently reported Medical Therapy of Prostatic Symptoms trial has convincingly demonstrated superior outcomes with combination therapy compared with monotherapy, unlike previous trials of shorter duration. The ability of 5 alpha-reductase inhibitors to prevent disease progression was also confirmed. Newer roles for 5 alpha-reductase inhibitors are also being defined. Finasteride has been shown to reduce and control benign prostatic hyperplasia-related haematuria, although its value in controlling perioperative bleeding is less clear. Their role as chemopreventive agents for prostate cancer is also under investigation.

SUMMARY

Recent studies have both clarified and extended the roles of 5 alpha-reductase inhibitors in benign prostatic hyperplasia, and these may expand further if chemopreventive abilities are proved. In addition, dual isoenzyme inhibition will soon be available.