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PubMedDate not supplied

The impact of 5-alpha-reductase inhibitors on the number of prostatectomies for benign prostatic hyperplasia.

To determine the impact of a 5-alpha-reductase inhibitor on the need for surgical treatment of symptomatic benign prostatic hyperplasia (BPH) in clinical urologic practice, we retrospectively reviewed records of 794 patients treated with pharmacotherapy or surgery (or both). The number of transurethral resections of the prostate (TURPs) performed during the 30 months since introduction of finasteride was compared with the number performed during the 30 months before finasteride became available. The alpha-blockers doxazosin and prazosin were used during both times for the treatment of BPH. Of the 619 patients treated with drugs, 88.5% received finasteride for a mean of 249.6 days. The alpha-blockers, either alone or combined with finasteride, were prescribed for 11.5% of patients for a mean of 179 days. In the 30 months after the introduction of finasteride, 65 patients underwent TURP: 28 of these men had initially received drug therapy. In contrast, 138 TURPs were performed in the 30 months prior to the availability of finasteride. The use of a 5-alpha-reductase inhibitor as primary medical therapy for symptomatic BPH decreased the number of prostatectomies by 52.9% (65 vs 138). This observation warrants corroboration through additional prospective studies.

Adrenergic alpha-Antagonists↗
PubMed2002

Terazosin for treating symptomatic benign prostatic obstruction: a systematic review of efficacy and adverse effects.

OBJECTIVE: To systematically review and evaluate the effectiveness and adverse effects of the alpha-antagonist, terazosin, for treating urinary symptoms associated with benign prostatic obstruction (BPO). METHODS: Studies were sought and included in the review if they were randomized trials of at least 1 month duration, involved men with symptomatic BPO and compared terazosin with placebo or active controls. The study, patient characteristics and outcome data were extracted in duplicate onto standardized forms using a prospectively developed protocol. RESULTS: Seventeen studies involving 5151 men met the inclusion criteria, i.e. placebo-controlled (10), alpha-blockers (seven), finasteride alone or combined with terazosin and placebo (one), and microwave therapy (one). The study duration was 4-52 weeks; the mean age of the men was 65 years and 82% were white. Baseline urological symptom scale scores and flow rates showed that men had moderate BPO. Efficacy outcomes were rarely reported in a way that allowed for data pooling, but indicated that terazosin improved symptom scores and flow rates more than did placebo or finasteride, and similarly to other alpha-antagonists. The pooled mean percentage improvement for the Boyarsky symptom score was 37% for terazosin and 15% for placebo (four studies). The mean percentage improvement for the American Urological Association symptom score was 38%, compared with 17% and 20% for placebo and finasteride, respectively (two studies). The pooled mean improvement in the International Prostate Symptom Score of 40% was similar to that with tamsulosin (43%). Peak urinary flow rates improved more with terazosin (22%) than with placebo (11%) and finasteride (15%), but did not differ significantly from the other alpha-antagonists. The percentage of men discontinuing terazosin was comparable with those receiving placebo and finasteride, but greater than with other alpha-antagonists. Adverse effects were greater than with placebo and included dizziness, asthenia, headache and postural hypotension. CONCLUSIONS: The available evidence indicates that terazosin improves the symptoms and flow rates associated with BPO; it was more effective than placebo or finasteride and similar to other alpha-antagonists. Adverse effects were generally mild but more frequent than with other alpha-antagonists and associated with a two- to four-fold increase in treatment discontinuation.

Adrenergic alpha-Antagonists↗
PubMed1996

[Finanseride in symtomatic benign prostatic hyeprtrophy. A 2-year placebo-controlled study].

The efficacy and safety of treatment with finasteride 5 mg daily for 24 months was assessed in this multicentre double blind placebo-controlled study including 707 patients with moderately symptomatic benign prostatic hyperplasia. Efficacy parameters were changes in voiding- and bladder storage symptoms assessed by a validated symptom score, changes in maximum urinary flow rate and changes in the prostate volume. In the finasteride patients, symptom score improved during the whole study with a significant difference between active treatment and placebo after 24 months (p < 0.01). Maximum flow rate increased in finasteride treated patients resulting in a difference between these and the placebo treated patients of 1.8 ml/s after 24 months (p < 0.01). Prostate volume was reduced by 19% in the finasteride treated patients versus an increase of 12% in the placebo treated patient group (p < 0.01). Finasteride was well tolerated. Patients receiving placebo progressed in symptoms after 16 months. Finasteride can halt the natural progression of moderately symptomatic BPH over a 24 month period.

Aged↗
PubMed2000

Serenoa repens for benign prostatic hyperplasia.

OBJECTIVES: This systematic review aimed to assess the effects of Serenoa repens in the treatment of Benign Prostatic Hyperplasia (BPH). SEARCH STRATEGY: Trials were searched in computerized general and specialized databases (MEDLINE, EMBASE, Cochrane Library, Phytodok), by checking bibliographies, and by contacting manufacturers and researchers. SELECTION CRITERIA: Trials were eligible if they (1) randomized men with BPH to receive preparations of Serenoa repens (alone or in combination) in comparison with placebo or other BPH medications, and (2) included clinical outcomes such as urologic symptom scales, symptoms, or urodynamic measurements. Eligibility was assessed by at least two independent observers. DATA COLLECTION AND ANALYSIS: Information on patients, interventions, and outcomes was extracted by at least two independent reviewers using a standard form. The main outcome measure for comparing the effectiveness of Serenoa repens with placebo or other BPH medications was the change in urologic symptom scale scores. Secondary outcomes included changes in nocturia and urodynamic measures. The main outcome measure for side effects was the number of men reporting side effects. MAIN RESULTS: 2939 men from18 randomized trials lasting 4 to 48 weeks were assessed. 16 trials were double-blinded and treatment allocation concealment was adequate in 9 studies. Compared with placebo, Serenoa repens improved urinary symptom scores, symptoms, and urinary flow measures. The weighted mean difference (WMD) for the urinary symptom score was -1.41 points (scale range 0-19), (95%CI = -2.52, -0.30, n = 1 study) and the risk ratio (RR) for self rated improvement was 1.75 (95%CI = 1.21, 2.54, n = 6 studies). The WMD for nocturia was -0.76 times per evening (95%CI = -1.22, -0.32; n = 10 studies). The WMD for peak urine flow was 1.93 ml/sec (95%CI = 0.72, 3.14, n = 8 studies). Compared with finasteride, Serenoa repens produced similar improvements in urinary symptom scores (WMD = 0.37 IPSS points (scale range 0-35), 95%CI = -0.45, 1.19, n = 2 studies) and peak urine flow (WMD = -0.74 ml/sec, 95%CI = -1.66, 0.18, n = 2 studies). Adverse effects due to Serenoa repens were mild and infrequent. Withdrawal rates in men assigned to placebo, Serenoa repens or finasteride were 7%, 9%, and 11%, respectively. REVIEWER'S CONCLUSIONS: The evidence suggests that Serenoa repens improves urologic symptoms and flow measures compared with placebo. Serenoa repens produced similar improvement in urinary symptoms and flow compared to finasteride and is associated with fewer adverse treatment events. The long term effectiveness, safety and ability to prevent BPH complications are not known.

Androgen Antagonists↗
PubMed2002

Terazosin for benign prostatic hyperplasia.

BACKGROUND: Lower urinary tract symptoms associated with benign prostatic obstruction (BPO) occur in up to 70% of men over the age of 60 years. To relieve these bothersome symptoms, treatment options include alpha-antagonists, also know as alpha-blockers. OBJECTIVES: We conducted a systematic review to evaluate the effectiveness and adverse effects of the alpha-blocker, terazosin, for treatment of urinary symptoms associated with BPO. SEARCH STRATEGY: Trials were searched in computerized general and specialized databases (MEDLINE, Cochrane Library), by checking bibliographies, and by contacting manufacturers and researchers. SELECTION CRITERIA: Studies were included if they (1) were randomized trials of at least 1 month duration, and (2) included men with symptomatic BPO and compared terazosin with placebo or active controls. DATA COLLECTION AND ANALYSIS: Study, patient characteristics and outcomes data were extracted in duplicate onto standardized forms utilizing a prospectively developed protocol. The main outcome measure for comparing the effectiveness of terazosin with placebo or other BPO medications was change in urological symptoms as measured by validated symptom scores. Secondary outcomes included urodynamic measures. The main outcome measure for adverse effects was the number of men reporting side effects. We also evaluated the number of men withdrawing from treatment and the number withdrawing due to adverse effects. MAIN RESULTS: 17 studies involving 5,151 subjects met inclusion criteria (placebo-controlled (10); alpha-blockers (7); finasteride alone or in combination with terazosin as well as placebo (1); microwave therapy (TUMT) (1). Study duration ranged from 4-52 weeks. Mean age was 65 years and 82% of men were white. Baseline urologic symptom scale scores and flow rates demonstrated that men had moderate BPO. Efficacy outcomes were rarely reported in a fashion that allowed for data pooling but indicated that terazosin improved symptom scores and flow rates more than placebo or finasteride and similarly to other alpha antagonists. The pooled mean percentage improvements for the Boyarsky symptom score was 37% for terazosin versus 15% for placebo (n=4 studies). The mean percentage improvement for the American Urological Association symptom score (AUA) was 38% compared to 17% and 20% for placebo and finasteride, respectively (n = 2 studies). The pooled mean improvement in the International Prostate Symptom Score (IPSS) (40%) was similar to tamsulosin (43%). Peak urine flow rates improved greater with terazosin (22%), than placebo (11%) and finasteride (15%) but did not differ significantly from the other alpha-blockers. The percentage of men discontinuing terazosin was comparable to men receiving placebo and finasteride but was greater then with other alpha-antagonists. Adverse effects were greater than placebo and included dizziness, asthenia, headache and postural hypotension. REVIEWER'S CONCLUSIONS: The available evidence suggests that terazosin improves urinary symptoms and flow measures associated with BPO. Effectiveness is superior to placebo or finasteride, similar to other alpha-blockers but less than TUMT. Adverse effects were generally mild but more frequent than other alpha-blockers and associated with between a two-four fold increase in treatment discontinuation.

Adrenergic alpha-Antagonists↗
PubMed1996

FCE 28260, a new 5 alpha-reductase inhibitor: in vitro and in vivo effects.

FCE 28260 is a novel inhibitor of 5 alpha-reductase (5 alpha R), the enzyme responsible for the conversion of testosterone (T) to 5 alpha-dihydrotestosterone (DHT). The compound caused inhibition of rat and human prostatic enzymes, with IC50 values of 15 and 16 nM, respectively, compared to the values of 30 and 52 nM shown by finasteride. Furthermore, FCE 28260 was highly potent in inhibiting human recombinant 5 alpha R type 2 and 1 isozymes, showing IC50 values of 3.3 and 36 nM, and therefore it was more potent than finasteride (IC50 values of 8.5 and 470 nM) on both isozymes. In prepubertal, T-implanted castrated rats, FCE 28260, given orally for 7 days, reduced ventral prostate growth with an ED50 of 0.8 mg/kg, i.e. five times lower than that shown by finasteride. No anti-androgenic activity in DHT-implanted castrated rats was found up to 10 mg/kg/day. In adult male rats, FCE 28260 reduced prostatic DHT concentrations 6 h after oral dosing with a potency similar to that of finasteride (65% reduction at 1 mg/kg) but was found to be markedly more potent than the reference compound at 24 h (74% reduction in prostate DHT at 10 mg/kg, compared to 26% reduction induced by finasteride). These results indicate that FCE 28260 represents a marked improvement over finasteride.

5-alpha Reductase Inhibitors↗
PubMed1998

A five-alpha reductase inhibitor or an antiandrogen prevents the progression of microscopic prostate carcinoma to macroscopic carcinoma in rats.

BACKGROUND: The objective of this study was to elucidate the prophylactic effects of 5-alpha reductase inhibitor (e.g., finasteride) and a pure antiandrogen (e.g., casodex) on rat prostate carcinogenesis and to determine whether latent prostate carcinoma can be prevented to develop to clinically significant cancer by use of these drugs. METHODS: F344 rats were subcutaneously administered 3,2'-dimethyl-4-aminobiphenyl (DMAB) for the first 20 weeks and testosterone propionate throughout the 60-week study. Finasteride (5 mg/kg and 15 mg/kg, 2 times per week) and casodex (15 mg/kg, 30 mg/kg, and 60 mg/kg, 3 times per week) were administered orally during the last 40 weeks of the study. Tumors were classified as visible prostate carcinoma when they could be recognized with the naked eye and as microscopic prostate carcinoma when detectable only with a microscope. RESULTS: The incidence of visible prostate carcinoma was 51% (18 of 35 rats) in the positive control group, whereas it was 40% (4 of 10 rats) in the finasteride 5 mg/kg group, 16.7% (2 of 12 rats, P = 0.0091) in the finasteride 15 mg/kg group, 20% (4 of 20 rats, P = 0.05) in the casodex 15 mg/kg group, 14.3% (3 of 21 rats, P = 0.0008) in the casodex 30 mg/kg group, and 0% (0 of 11 rats, P = 0.0002) in the casodex 60 mg/kg group. On the other hand, when visible carcinomas and microscopic carcinomas were handled together, only casodex 60 mg/kg significantly inhibited the carcinogenesis rate. CONCLUSIONS: Finasteride achieved dose-dependent inhibition of macroscopic rat prostate carcinogenesis, and casodex also inhibited macroscopic prostate carcinogenesis. However, both drugs showed insufficient prevention of carcinogenesis at the microscopic level. These findings indicate that, in clinical medicine as well, such drugs may also be able to prevent the progression of latent prostate carcinoma to life-threatening disease.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2001

Clinical application of 5alpha-reductase inhibitors.

The inhibitors of 5alpha-reductase isoenzymes (1 and 2) can be schematically divided in three groups according they substrate specificity: a) pure or preferential inhibitor of 5alpha-reductase 1; b) pure or preferential inhibitor of 5alpha-reductase 2; c) dual inhibitors. Despite the fact that several steroidal and non-steroidal inhibitors have been synthesized and experimented in pharmacological models, only finasteride has been extensively used for clinical purposes. The largest application of finasteride in man has been human benign prostative hyperplasia (BPH). In addition, finasteride has been recently used for treatment of male baldness with a 50% of objective response. In women, finasteride has been used in some control trials for treatment of hirsutism with an objective favorable response. In conclusion, finasteride appears be useful for BPH, baldness and hirsutism (with caution) treatment. On the basis of experimental observations on distribution of 1 and 2 isoenzymes in human skin, scalp and prostate, the dual inhibitors should be more indicated for treatment of BPH and baldness. Similarly, the dual inhibitors seem indicated in attempting to prevent prostatic cancer. The pure 5alpha-reductase 1 inhibitors seem the ideal drugs for treatment of acne and hirsutism.

5-alpha Reductase Inhibitors↗
PubMed2001

Hormonal treatment of patients with benign prostatic hyperplasia: pros and cons.

The recognition that dihydrotestosterone is a "major player" in the development of benign prostatic hyperplasia (BPH) provided an impetus for the development of a 5a-reductase inhibitor, finasteride. During the past 5 years, a number of publications have noted that alpha blockers appear more efficacious than finasteride. This article reviews the role of hormones (particularly finasteride) in the treatment of lower urinary tract symptoms caused by BPH. These observations indicate that finasteride has a role in the management of larger prostates. Long-term use reduces the development of urinary retention and need for invasive procedures such as transurethral prostatectomy. The major adverse impact of finasteride is its effect on the patient's libido and sexual function. This is a less morbid problem for the elderly than the potential syncope associated with the use of alpha blockers. A greater understanding of the interaction of hormones on prostate receptors will provide newer tools for the treatment of BPH.

Enzyme Inhibitors↗
PubMed2005

Attenuating 5alpha-pregnane-3alpha-ol-20-one formation in the hippocampus of female rats increases pentylenetetrazole-induced seizures.

Progesterone has antiseizure effects, which may be due to the actions of its 5alpha-reduced metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP). Whether metabolism of progesterone to 3alpha,5alpha-THP in the hippocampus is essential for its antiseizure effects was investigated. In Experiment 1, ovariectomized rats were administered subcutaneous progesterone (500 microg) or vehicle (sesame oil), followed 1 hour later by subcutaneous administration of an inhibitor of the 5alpha-reductase enzyme, finasteride (50 mg/kg), or vehicle (90% sesame oil, 10% ethanol). Administration of progesterone increased the latency to, and decreased the number of, tonic seizures and increased hippocampal 3alpha,5alpha-THP levels, compared with vehicle. Administration of finasteride with progesterone attenuated progesterone's antiseizure effects and decreased levels of 3alpha,5alpha-THP in the hippocampus. Finasteride administration alone did not alter ictal behavior or 3alpha,5alpha-THP levels compared with vehicle. In Experiment 2, ovariectomized rats were administered subcutaneous progesterone (500 microg) or vehicle (sesame oil), followed 1 hour later by bilateral infusions of finasteride (10 microg) or vehicle (beta-cyclodextran) into the hippocampus. Administration of finasteride to the hippocampus of progesterone-primed rats significantly increased ictal activity and decreased hippocampal 3alpha,5alpha-THP levels, compared with progesterone administration alone. These data suggest that formation of 3alpha,5alpha-THP in the hippocampus is important for progesterone's antiseizure effects.

Animals↗
PubMed1999

Treatment of hirsutism: comparisons between different antiandrogens with central and peripheral effects.

OBJECTIVE: To compare the clinical and endocrinologic effects of cyproterone acetate (CPA), an antiandrogen with progestational activity; flutamide, a nonsteroidal antiandrogen, and finasteride, an inhibitor of 5alpha-reductase. DESIGN: Randomized, open, controlled clinical study. SETTING: Department of Obstetrics and Gynecology, University of Pisa, Pisa, Italy. PATIENT(S): Forty-five hirsute women were enrolled in the study: 29 were hyperandrogenic and 16 had idiopathic hirsutism. Three women dropped out of the study. INTERVENTION(S): Women were randomly treated with finasteride (5 mg/d; n = 14), CPA (25 mg plus ethinyl E2 (EE); n = 13), or flutamide (500 mg/d; n = 15) for 1 year. MAIN OUTCOME MEASURE(S): Hirsutism was assessed using the Ferriman-Gallwey method. Levels of total and free T, androstenedione (A), DHEAS, sex hormone-binding globulin, dihydrotestosterone, and 3alpha-androstanediol glucuronide were evaluated at the beginning of the study and every 3 months. RESULT(S): Treatment with finasteride, flutamide, and CPA significantly decreased the Ferriman-Gallwey score. The percent decreases in the hirsutism score induced by the different treatments were similar. Treatment with CPA plus EE significantly decreased levels of total and free T, A, dihydrotestosterone, and 3alpha-androstanediol glucuronide. These parameters were unchanged with flutamide therapy. Finasteride significantly increased total T levels but reduced dihydrotestosterone and 3alpha-androstanediol glucuronide concentrations. CONCLUSION(S): Finasteride, CPA, and flutamide are equally effective in decreasing hirsutism, despite different mechanisms of action.

Adolescent↗
PubMedDate not supplied

5 alpha-reductase inhibitors, chemical and clinical models.

An active site model of 5 alpha-reductase type 2 isoenzyme on an "active-analog approach" and based on 4-azasteroidal inhibitors has been constructed to evaluate the effects on the inhibitory potency of substituents on the steroid A ring. This model has proven able to predict the potential inhibitory activity of 19-nor-10-azasteroid and 6-azasteroid compounds. A model for the evaluation of clinical efficacy of an inhibitor, based on in vitro data, has also been developed and applied to finasteride. This inhibitory potency evaluation of finasteride in human scalp homogenates, plus pharmacokinetic data, allows the calculation of a theoretical in situ inhibition value for human scalp. From the IC50 curve of finasteride in scalp homogenates, it is possible to calculate that for an inhibition level similar to that obtained in prostate with 5 mg of finasteride, the necessary plasma concentration of the drug is 1 microM, a level obtained after the acute administration of 50 mg of finasteride.

Cholestenone 5 alpha-Reductase↗
PubMed1996

Inhibition of human steroid 5alpha reductases type I and II by 6-aza-steroids: structural determinants of one-step vs two-step mechanism.

We have discovered that 17beta-[N,N-(diethyl)carbamoyl]-6-azaandrost-4-en-3-one is a time-dependent inhibitor of type II 5alpha-reductase, as is the drug finasteride. Unlike finasteride, the 6-aza-steroid is not a time-dependent inhibitor of type I 5 alpha-reductase. Finasteride inhibition of type II enzyme proceeds in a two-step mechanism. At pH 6 and 37 degrees C, an initial finasteride-reductase complex is formed with a K(i)(app) of 11.9 +/- 4.1 nM. In a second step, an irreversible complex is formed with a rate constant of inactivation of 0.09 +/- 0.01 s(-1). In contrast, the 6-aza-steroid is a reversible inhibitor. From the results of a simplified mathematical analysis, based on the rapid equilibrium approximation, the inhibitor and the enzyme form an initial complex with a K(i) of 6.8 +/- 0.2 nM. The reversible formation of a final complex, with an overall K(i) of 0.07 +/- 0.02 nM, is characterized by a first-order isomerization rate constant 0.0035 +/- 0.0001 s(-1) for the forward step and 0.00025 +/- 0.00006 s(-1) for the backward step. All rate constants for the two-step mechanism were obtained by using a general numerical integration method. The best fit values for the association and dissociation rate constants were 5.0 microM(-1) s(-1) and 0.033 +/- 0.008 s(-1), respectively, and the isomerization rate constants were 0.0035 +/- 0.007 s(-1) and 0.000076 +/- 0.000019 s(-1). These values correspond to an initial K(i) of 6.5 nM and an overall dissociation constant of 0.14 nM. The data presented here show that both finasteride and the 6-aza-steroid analogs are potent against type II 5alpha-reductase, although their mechanisms of inhibition are different.

5-alpha Reductase Inhibitors↗
PubMed2001

Ventral tegmental area infusions of inhibitors of the biosynthesis and metabolism of 3alpha,5alpha-THP attenuate lordosis of hormone-primed and behavioural oestrous rats and hamsters.

The importance of progesterone biosynthesis and metabolism to 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), which exerts its effects via GABAA/benzodiazepine receptor complexes (GBRs) rather than intracellular progestin receptors (PRs), was investigated for its effects on sexual receptivity. Epostane, a 3beta-hydroxysteroid dehydrogenase inhibitor, blocks progesterone and 3alpha,5alpha-THP biosynthesis. Finasteride, a 5alpha-reductase inhibitor, blocks the metabolism of progesterone to dihydroprogesterone (DHP), which is subsequently metabolized to 3alpha,5alpha-THP. Indomethacin, a 3alpha-hydroxysteroid oxidoreductase inhibitor, blocks DHP's metabolism to 3alpha,5alpha-THP, and its oxidation to DHP. Epostane, finasteride, indomethacin or vehicle were infused intracranially in the ventral tegmental area (VTA) of hormone-primed or naturally receptive rats and hamsters and sexual behaviour was recorded. Epostane, finasteride and indomethacin to the VTA significantly reduced lordosis, compared to vehicle infusions, in hormone-primed and behavioural oestrous rats and hamsters. Radioimmunoassay revealed that concentrations of midbrain 3alpha,5alpha-THP were reduced following epostane, finasteride or indomethacin infusions that significantly decreased lordosis. Immunocytochemistry for 3alpha,5alpha-THP revealed the number of immunoreactive cells were significantly reduced in the VTA following epostane, finasteride or indomethacin infusion to the VTA, but not other midbrain sites. These data suggest that biosynthesis of progestins, and the metabolism of progesterone to 3alpha,5alpha-THP in the VTA, are important for progestin-facilitated sexual receptivity of rats and hamsters.

Androstenols↗
PubMed2001

Neurosteroid withdrawal model of perimenstrual catamenial epilepsy.

PURPOSE: Perimenstrual catamenial epilepsy, the increase in seizure frequency that some women with epilepsy experience near the time of menstruation, may in part be related to withdrawal of the progesterone metabolite allopregnanolone, an endogenous anticonvulsant neurosteroid that is a potent positive allosteric gamma-aminobutyric acidA (GABA(A)) receptor modulator. The objective of this study was to develop an animal model of perimenstrual catamenial epilepsy for use in evaluating drug-treatment strategies. METHODS: A state of prolonged high serum progesterone (pseudopregnancy) was induced in 26-day-old female rats by sequential injection of pregnant mares' serum gonadotropin and human chorionic gonadotropin. Neurosteroid withdrawal was induced by treatment with finasteride (100 mg/kg, i.p.), a 5alpha-reductase inhibitor that blocks the conversion of progesterone to allopregnanolone. Plasma progesterone and allopregnanolone levels were measured by gas chromatography/electron capture negative chemical ionization mass spectrometry. Seizure susceptibility was evaluated with the convulsant pentylenetetrazol (PTZ). RESULTS: Plasma allopregnanolone levels were markedly increased during pseudopregnancy (peak level, 55.1 vs. control diestrous level, 9.3 ng/mL) and were reduced by 86% 24 h after finasteride treatment (6.4 ng/mL). Progesterone levels were unaffected by finasteride. After finasteride-induced withdrawal, rats showed increased susceptibility to PTZ seizures. There was a significant increase in the number of animals exhibiting clonic seizures when challenged with subcutaneous PTZ (60 mg/kg) compared with control pseudopregnant animals not undergoing withdrawal and nonpseudopregnant diestrous females. The CD50 (50% convulsant dose) was 46 mg/kg, compared with 73 mg/kg in nonwithdrawn pseudopregnant animals and 60 mg/kg in diestrous controls. The threshold doses for induction of various seizure signs, measured by constant intravenous infusion of PTZ, were reduced by 30-35% in neurosteroid-withdrawing animals compared with control diestrous females. No change in threshold was observed in pseudopregnant rats treated from days 7 to 11 with finasteride, demonstrating that high levels of progesterone alone do not alter seizure reactivity. CONCLUSIONS: Neurosteroid withdrawal in pseudopregnant rats results in enhanced seizure susceptibility, providing an animal model of perimenstrual catamenial epilepsy that can be used for the evaluation of new therapeutic approaches.

20-alpha-Dihydroprogesterone↗
PubMed2004

Doxazosin for treating lower urinary tract symptoms compatible with benign prostatic obstruction: a systematic review of efficacy and adverse effects.

OBJECTIVE: To evaluate the efficacy and adverse effects of doxazosin for treating lower urinary tract symptoms (LUTS) compatible with benign prostatic obstruction (BPO). METHODS: Randomized controlled trials were included in the meta-analysis if: the study duration was > or = 1 month; the study involved men with symptomatic BPO; and doxazosin was compared with placebo or active controls. Study and patient characteristics and outcome data were extracted in duplicate onto standardized forms using a prospectively developed protocol. RESULTS: Thirteen studies involving 6033 men with (mean age 64 years) met the inclusion criteria; 10 were placebo-controlled, including two with combined doxazosin/finasteride therapy and finasteride monotherapy arms. Three trials were a comparison with other alpha-blockers. The study duration was 1-54 months. The mean baseline symptom scores and peak urinary flow (PUF) rates were indicative of moderate BPO. Doxazosin gave significant improvements in LUTS, assessed by symptom scores, vs placebo and finasteride in the short- to long-term. Two long-term studies (1 and 4 years) reported mean changes from baseline for the International Prostate Symptom Score of - 8.3 and - 6.6 points (-49% and - 39%) for doxazosin and - 5.7 and - 4.9 points (-33% and - 29%) for placebo, respectively. Doxazosin significantly increased PUF rates vs placebo. In pooled results from three studies, the weighted mean difference in the mean change from baseline vs placebo was 1.6 mL/s (95% confidence interval 1.2-2.1). Efficacy was comparable with other alpha1-blockers. In the long-term (>4 years) doxazosin was no better then finasteride in improving PUF. Combined doxazosin and finasteride significantly reduced the risk of overall clinical progression of BPO vs each drug separately in men followed for >4 years. Absolute risk reductions vs placebo were 11.3%, 6.9% and 6.4% for combined therapy, doxazosin and finasteride, respectively (P < 0.001). Improvements in symptom scores and PUF were also significantly greater with combined than monotherapy, and the former reduced the need for invasive treatment for BPO and the risk of long-term urinary retention, although the absolute reductions in risk vs placebo were small (<4%). Dizziness and fatigue were significantly more common with doxazosin than placebo (11% vs 7%, and 6% vs 3%, respectively). Adverse events reported for combined therapy were similar to those with each monotherapy. CONCLUSION: The evidence indicates that doxazosin is effective and generally well tolerated for improving LUTS and PUF in men with symptomatic BPO. Combined therapy was better than doxazosin alone in reducing the risk of clinical progression of BPO and other long-term complications related to BPO.

Adrenergic alpha-Antagonists↗
PubMed1996

Treatment of benign prostatic hyperplasia with 5-alpha-reductase inhibitor: morphological changes in patients who fail to respond.

AIMS: To describe the prostatic adenectomy specimens of six patients with symptomatic benign prostatic hyperplasia (BPH) who failed to respond to long term treatment with a 5-alpha-reductase inhibitor, finasteride. METHODS: Histological sections from six cases of BPH who had been treated with finasteride were investigated. Five patients were prescribed 5 mg finasteride daily for six months and one patient 5 mg daily for 12 months. The patients underwent adenectomy as their urethral obstruction failed to resolve. Twenty cases of untreated BPH served as controls. RESULTS: In patients taking finasteride for six months the prostatic adenectomy specimens showed a reduction in the size of the prostate and an increase in the stroma:epithelial and stroma:lumen ratios compared with controls. The size of the ducts and acini was not as uniform as in the controls. In particular, some ducts and acini were still lined by a bistratified epithelium similar to that found in controls but lacked undulations at the epithelial border; other ducts/acini were atrophic. Some scattered clusters of small acini with a focally fragmented basal cell layer were observed in two of the five treated cases. One prostatic adenectomy specimen, from the patient treated for one year, showed extensive lobular atrophy and diffuse squamous and transitional cell metaplasia. At the periphery of the transition zone, there was a complex intra-acinar papillary-cribriform proliferation of clear cells without nuclear atypia, similar to clear cell papillary hyperplasia. The periurethral region showed stromal nodules in both patients and controls. CONCLUSIONS: Morphological evaluation of finasteride treated BPH showed changes in the lobules of the transition zone, but not in the periurethral stroma.

5-alpha Reductase Inhibitors↗
PubMed2000

Medical therapy for benign prostatic hyperplasia: a review of the literature.

OBJECTIVE: To review the existing evidence regarding the efficacy and safety of medical therapy for lower urinary tract symptoms (LUTS) indicative of benign prostatic hyperplasia (BPH). To assess randomised controlled trials investigating the six alpha-adrenergic receptor antagonists (alpha-blockers), prazosin, alfuzosin, indoramin, terazosin, doxazosin, and tamsulosin, that benefit patients by relaxing prostatic smooth muscle, and the anti-androgen, finasteride, that mediates its more long-term benefits by reducing prostate size. RESULTS: This review suggests that both classes of drug offer significant improvement in criteria used to evaluate symptomatic BPH and can be effective whilst being acceptably safe. Furthermore, the therapeutic efficacy of all contemporary alpha-blockers appear similar, both in terms of symptom relief and urodynamic improvements. Randomised controlled trials have additionally demonstrated that finasteride therapy can provide improvement in terms of quality of life indices, prostate volume, and risks of progressing to acute urinary retention or prostatic surgery. While alpha-blockers have a rapid onset of action, likely to produce a therapeutic result within weeks, regardless of whether prostatic enlargement or bladder outlet obstruction is present, finasteride appears to be effective for more long-term therapy for up to 4 years, but only in alleviating symptoms when they are associated with a significantly large prostate. Neither finasteride nor the alpha(1a)-receptor-selective blocker, tamsulosin, are associated with the lowering of blood pressure and incidence of cardiovascular side effects that are apparent with other less selective alpha-blocker therapies such as dizziness and postural hypertension. They are, however, both associated with an increased risk of sexual dysfunction, albeit less than those associated with surgical intervention. Whereas tamsulosin is associated only with ejaculatory dysfunction, finasteride is additionally linked to decreased libido and impotence.

Adrenergic alpha-Antagonists↗