The use of saw palmetto versus finasteride for the treatment of prostatitis/chronic pelvic pain syndrome.
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The development of finasteride (PROSCAR, Merck & Co., Whitehouse Station, NJ) for the treatment of benign prostatic hyperplasia (BPH) has had variable results. Numerous short-term and long-term studies comparing finasteride with placebo have been reported. The results suggest that, physiologically, treatment with finasteride significantly decreases levels of both serum and intraprostatic dihydrotestosterone about 70% to 80% from baseline. In addition, total gland size decreases significantly-about 15% to 25% from baseline-particularly in the area of the periurethral zone of the prostate after finasteride treatment. Baseline prostate size has been found to have a relation to efficacy of finasteride treatment. The larger the prostate at baseline, the greater the urinary flow rate increase and symptom score decrease compared with placebo. Health-related quality-of-life parameters improved in those taking finasteride. In studies evaluating combination therapy, no significant differences were noted between those treated with an alpha blocker, such as terazosin or doxazosin in combination with finasteride, and those receiving an alpha blocker alone. Long-term finasteride versus placebo studies, such as the PROSCAR Long-Term Efficacy and Safety Study (PLESS), suggest that long-term medical therapy with finasteride affects the natural history of the disease as manifested by the decrease in rates of acute urinary retention and surgery. In patients who are "therapeutic responders," the degree of symptomatic improvement in those treated with finasteride appears to be equal to that seen in patients receiving alpha blockers. Prostate cancer detection rates did not differ between those treated with finasteride and those receiving a placebo. The results of these studies suggest that physicians must evaluate what role finasteride plays in the spectrum of available options for the treatment of BPH and lower urinary tract symptoms. Baseline parameters, such as prostate volume, prostate-specific antigen values, and whether to administer finasteride in combination with alpha blockers, are among the factors that will determine the appropriateness of such therapy.
PURPOSE: We determine the effect of placebo, finasteride, terazosin and a combination of drugs on bother due to symptoms, quality of life and patient perception of improvement, and identify baseline clinical factors that predict clinical response to medical therapy. MATERIALS AND METHODS: A total of 1,229 subjects with clinical benign prostatic hyperplasia (BPH) were randomized to 1 year of placebo, finasteride, terazosin or drug combination. The primary outcome measures were American Urological Association (AUA) symptom score and peak flow rate. Relevant secondary outcome measures were symptom problem score, BPH impact score and global rating of improvement. RESULTS: Group mean differences in symptom problem and BPH impact scores between the finasteride versus placebo, and terazosin versus combination groups were not statistically or clinically significant. Group mean differences in all outcome measures were highly statistically significant between the terazosin and finasteride, and combination and finasteride groups. The percentage of subjects who rated improvement as marked or moderate with placebo, finasteride, terazosin and combination was 39, 44, 61 and 65%, respectively. In the subsets of men in the placebo, finasteride, terazosin and combination groups with prostates greater than 50 cm.3 group mean decrease from baseline in AUA symptom score was -2.5, -3.6, -6 and -7, group mean increase in peak flow rate was 0.6, 2.7, 3.6 and 3.7 ml. per second, group mean decrease in symptom problem score was -2.2, - 1.9, -3.1 and -4.5, and group mean decrease in BPH impact score was -0.6, -0.3, -1.1 and -1.5, respectively. A correlational analysis failed to show a significant relationship between baseline prostate volume and treatment response to finasteride. There was a significant but weak relationship between change in AUA symptom score and peak flow rate in the finasteride and combination groups. The symptom responses with terazosin were independent of baseline peak flow rate. CONCLUSIONS: In men with clinical BPH finasteride and placebo are equally effective, while terazosin and combination are significantly more effective. In men with clinical BPH and large prostates the advantage of finasteride over placebo in terms of symptom reduction, impact on bother due to symptoms and quality of life is small at best, while the advantage of terazosin and combination over finasteride and placebo is highly significant. Baseline prostate volume was not a predictor of response to finasteride in the overall study population. On the basis of our results alpha1 blockers, such as terazosin, should be first line medical treatment for BPH.
PURPOSE: To assess the estimated effect of finasteride prevention of prostate cancer on overall survival. METHODS: Data for our decision tree model came from men in the two arms (finasteride or placebo) of the Prostate Cancer Prevention Trial (PCPT) and from clinically localized prostate cancer patients studied for long-term survival outcomes. Our model compared survival outcomes for men treated with finasteride or placebo. Prostate cancer rates were based on the 7-year period prevalence of prostate cancer detected in the PCPT; survival probabilities were abstracted from the long-term outcome studies. We assessed variability in the PCPT and long-term survival studies to test the variability of our model. RESULTS: Survival advantages for a finasteride-treated (v those not treated with finasteride) population include gains of 1.7 months in 15-year cause-specific survival (assuming finasteride-altered Gleason scores and prostate cancer prevalence rates in the PCPT), of up to 3 months for cancers treated conservatively or surgically (assuming finasteride does not alter Gleason scores), and of 0.35 months (assuming the rate of cancers detected by for-cause biopsies in the PCPT), which increased to 1.7 months when assuming a 30% rate of biopsy-detected cancer in the PCPT placebo group. Model-variability analyses support several survival benefits associated with finasteride (eg, the uniform benefits assuming finasteride does not alter Gleason scores) but question certain others (eg, in 15-year recurrence-free survivals assuming finasteride does alter Gleason scores). CONCLUSION: Finasteride can impart survival benefits according to our model, especially when we assume that finasteride does not alter Gleason scores.
CGP 53153 (N-2-(cyano-2-propyl)-3-oxo-4-aza-5alpha-androst-1-ene-17beta-carb oxamide) is a steroidal inhibitor of 5alpha-reductase, the enzyme which effects the conversion of testosterone (T) to 5alpha-dihydrotestosterone (DHT). In vitro, CGP 53153 competitively inhibited rat microsomal 5alpha-reductase from prostate by 50% (IC50) at a concentration of 36nM compared to the reference compound finasteride which inhibited 5alpha-reductase with an IC50 of 11 nM in the same system. In vivo, inhibition of 5alpha-reductase activity was characterized in three different test systems. Inhibition of 5alpha-reductase activity was first assessed in a standard test designed to compare directly the potency of different 5alpha-reductase inhibitors. This test assesses potency through the inhibition of prostate growth in juvenile castrate male rats treated with a standard dose of T-propionate (1 mg/kg, s.c.) and a 5alpha-reductase inhibitor administered orally at various doses for 4 days. CGP 53153 and finasteride significantly reduced T-propionate-mediated prostate growth by about 25% (ED25) compared to T-propionate-treated controls at oral doses of 0.01 and 0.1 mg/kg, respectively. Second, the effects on prostate weight were studied in normal adult male rats treated orally once daily for 14 days with 1, 3 and 10 mg/kg CGP 53153 and with 10 mg/kg finasteride. CGP 53153 significantly reduced prostate weight at 3 and 10 mg/kg by 31% and 37%, respectively, compared to vehicle-treated controls, whereas the dose of 10 mg/kg finasteride did not significantly reduce prostate weight. Third, the effects on prostate volume were studied in normal 6-9-year-old male dogs treated orally once daily with 5 mg/kg CGP 53153 and with 5 mg/kg finasteride for 12 weeks. Prostate volume was monitored with magnetic resonance imaging every 2 weeks beginning 6 weeks before start of the treatment with 5alpha-reductase inhibitors and ending after a recovery period of 8 weeks after termination of treatment. Treatment for 12 weeks with both CGP 53153 and finasteride was equally effective in reducing prostate volume by more than 70% in individual dogs. Anti-androgenic potency of CGP 53153 and finasteride was assessed in juvenile castrate male rats treated with DHT-propionate (1 mg/kg, s.c.) and a 5alpha-reductase inhibitor (p.o.) for 4 days. Neither CGP 53153 nor finasteride given at a dose of 10 mg/kg had any significant effect on DHT-propionate-mediated prostate growth, whereas the reference anti-androgen flutamide given at a dose of 10 mg/kg reduced prostate weight to levels comparable to those seen in untreated castrate animals. For CGP 53153, the dose of 10 mg/kg is 1000-fold higher than the ED25 for 5alpha-reductase inhibition in vivo. In conclusion, both CGP 53153 and finasteride are potent inhibitors of the rat 5alpha-reductase enzyme system in vitro without showing any anti-androgenic effects in vivo. Both CGP 53153 and finasteride were equally potent in reducing prostate volume in aged male dogs, whereas in rats, CGP 53153 is up to 10 times more potent than finasteride in reducing prostate weight as shown in two different rat models.
OBJECTIVE: To investigate whether 5alpha-reductase inhibitor and dihydrotestosterone (DHT) play a role in spermatogenesis in male rats. METHODS: Thirty-two male rats were divided into 4 groups (Groups C, T, F and FT). Group C received plant oil injection and oral starch perfusion, Group T testosterone undecanoate (TU, 20 mg/kg) injection and oral starch perfusion, Group F plant oil injection and oral Finasteride perfusion, and Group FT TU (20 mg/kg) injection and oral Finasteride perfusion. Data on serum T and DHT, sperm count, sperm mobility and reproductive function were collected and analysed. RESULTS: (1) 5alpha-reductase inhibitor, Finasteride and TU reduced the weight of the testis and epididymis in the experiment groups compared with the negative control (Group C), but TU increased the weight of the prostate while Finasteride decreased it compared with the positive control (Group T). TU combined with Finasteride could counteract the effect of the weight increase of the prostate, but not that of the testis. (2) Finasteride, or Finasteride combined with TU, reduced the DHT but increased the testosterone level in comparison with the control group. (3) Both Finasteride and TU could inhibit epididymal sperm count and reproductive function compared with the control, but the effect was less significant in Group FT than in Group F. CONCLUSION: High dosages of 5alpha-reductase inhibitor, Finasteride, can suppress male reproductive function, but the inhibiting effect could be counteracted by administration of 5alpha-reductase inhibitor along with TU.
The development of human benign prostatic hyperplasia (BPH) clearly requires a combination of testicular androgens and the ageing process. Although the role of androgens as the causative factor for human benign prostatic hyperplasia is debated, they undoubtedly play, at least, a permissive role. The principal prostatic androgen is dihydrotestosterone. Although not elevated in human benign prostatic hyperplasia, dihydrotestosterone levels in the prostate remain at a normal level with ageing, despite a decrease in the plasma testosterone. Dihydrotestosterone (DHT) is generated by a reduction in testosterone. Two isoenzymes of 5alpha-reductase have been discovered. Type 1 is present in most tissues in the body where 5alpha-reductase is expressed, and is the dominant form in sebaceous glands. Type 2 5alpha-reductase is the dominant isoenzyme in genital tissues, including the prostate. Finasteride is a 5alpha-reductase inhibitor that has been used to treat BPH and male-pattern baldness. At doses used clinically, its major effect is to suppress type 2 5alpha-reductase, because it has a much lower affinity for the type 1 isoenzyme. Finasteride suppresses DHT by about 70% in serum and by as much as 85%-90% in the prostate. The remaining DHT in the prostate is likely to be the result of type 1 5alpha-reductase. The suppression of both 5alpha-reductase isoenzymes with GI198745 results in greater and more consistent containment of serum dihydrotestosterone than that observed with a selective inhibitor of type 2 5alpha-reductase. Physiological and clinical studies comparing dual 5alpha-reductase inhibitors, such as GI198745, with selective type 2, such as finasteride, will be needed to determine the clinical relevance of type 1 5alpha-reductase within the prostate. There have been two large, international multicentre, phase III trials published documenting the safety and efficacy of finasteride in treating human benign prostatic hyperplasia. Combining these two studies, randomised, controlled data are available for 12 months. Non-controlled extension of these data from a subset of patients, who elected to continue on the drug for 3, 4 and 5 years, are also available. Long-term medical therapy with finasteride can reduce clinically significant endpoints, such as acute urinary retention or surgery. According to the meta-analysis of six randomised, clinical trials with finasteride, finasteride is most effective in men with large prostates. A more effective dual inhibitor of type 1 and 2 human 5alpha-reductase may lower circulating dihydrotestosterone to a greater extent than finasteride and show advantages in treating human benign prostatic hyperplasia and other disease states that depend on dihydrotestosterone. A clinical evaluation of potent dual 5alpha-reductase inhibitors may help to define the relative roles of human type 1 and 2 5alpha-reductase in the pathophysiology of benign prostatic hyperplasia and other androgen-dependent diseases.
OBJECTIVE: The development of the human benign prostatic hyperplasia clearly requires a combination of testicular androgens and aging. Although the role of androgens as the causative factor for human benign prostatic hyperplasia is debated, they undoubtedly have at least a permissive role. The principal prostatic androgen is dihydrotestosterone (DHT). Although not elevated in human benign prostatic hyperplasia, DHT levels in the prostate remain at a normal level with aging, despite a decrease in the plasma testosterone. RESULTS: DHT is generated by reduction of testosterone. Two isoenzymes of 5alpha-reductase have been discovered. Type 1 is present in most tissues of the body where 5alpha-reductase is expressed and is the dominant form in sebaceous glands. Type2 5alpha-reductase is the dominant isoenzyme in genital tissues, including the prostate. Finasteride is a 5alpha-reductase inhibitor that has been used for the treatment of benign prostatic hyperplasia and male-pattern baldness. At doses used clinically, its major effect is through suppression of type 2 5alpha-reductase, because it has a much lower affinity for the type 1 isoenzyme. Finasteride suppresses DHT by about 70% in serum and by as much as 85-90% in the prostate. The remaining DHT in the prostate is likely to be the result of type 1 5alpha-reductase. Suppression of both 5alpha-reductase isoenzymes with GI198745 result in greater and more consistent suppression of serum dihydrotestosterone than that observed with a selective inhibitor of type 2 5alpha-reductase. Physiological and clinical studies comparing dual 5alpha-reductase inhibitors, such as GI198745, with selective type 2, such as finasteride, will be needed to determine the clinical relevance of type 1 5alpha-reductase within the prostate. Two large international multicenter, phase III trials have been published documenting the safety and efficacy of finasteride in the treatment of human benign prostatic hyperplasia. Combining these two studies, randomized, controlled data are available for 12 months. Noncontrolled extension of these data from a subset of patients, who elected to continue drug treatment for 3, 4 or 5 years, are also available. Long-term medical therapy with finasteride can reduce clinically significant endpoints such as acute urinary retention or surgery. According to the meta-analysis of six randomised clinical trial with finasteride, finasteride is most effective in men with large prostates. A more effective dual inhibitor of type 1 and 2 human 5alpha-reductase may lower circulating DHT to a greater extent than finasteride and show advantages in the treatment of human benign prostatic hyperplasia and other disease states that depend on DHT. CONCLUSION: Clinical evaluation of potent dual 5alpha-reductase inhibitors may help define the relative roles of human type 1 and 2 5alpha-reductase in the pathophysiology of benign prostatic hyperplasia and other androgen-dependent diseases.