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[Target enzyme].

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5-alpha Reductase Inhibitors↗

Disposition and pharmacokinetics of [14C]finasteride after oral administration in humans.

The disposition of [14C]finasteride, a competitive inhibitor of steroid 5 alpha-reductase, was investigated after oral administration of 38.1 mg (18.4 microCi) of drug in six healthy volunteers. Plasma, urine, and feces were collected for 7 days and assayed for total radioactivity. Concentrations of finasteride and its neutral metabolite, omega-hydroxyfinasteride (monohydroxylated on the t-butyl side chain), in plasma and urine were determined by HPLC assay. Mean excretion of radioactivity equivalents in urine and feces equaled 39.1 +/- 4.7% and 56.8 +/- 5.0% of the dose, respectively. The mean peak plasma concentrations reached for total radioactivity (ng equivalents), finasteride, and omega-hydroxyfinasteride were 596.5 +/- 88.3, 313.8 +/- 99.4, and 73.7 +/- 11.8 ng/ml, respectively, at approximately 2 hr; the mean terminal half-life for drug and metabolite was 5.9 +/- 1.3 and 8.4 +/- 1.7 hr, respectively. Of the 24-hr plasma radioactivity, 40.9% was finasteride, 11.8% was the neutral metabolite, and 26.7% was characterized as an acidic fraction of radioactivity. Binding of [14C]finasteride to plasma protein was extensive (91.3 to 89.8%), with a trend suggesting concentration dependency (range 0.02 to 2 micrograms/ml). Little of the dose was excreted in urine as parent (0.04%) or omega-hydroxyfinasteride (0.4%). Urinary excretion of radioactivity was largely in the form of acidic metabolite(s)--18.4 +/- 1.7% of the dose was eliminated as the omega-monocarboxylic acid metabolite. Finasteride was scarcely excreted unchanged in feces. In humans, finasteride is extensively metabolized through oxidative pathways.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Laboratory monitoring of androgenic activity in benign prostate hypertrophy treated with a 5 alpha-reductase inhibitor.

Testosterone and androstenedione are metabolized by 5 alpha- and 5 beta-reductases to androsterone (A) and etiocholanolone (E), respectively. These are excreted in the urine as conjugates, and the A/E ratio in normal men is usually greater than or equal to 1.5 (as opposed to 1 in women) because of the high 5 alpha-reductase activity in the prostate. The A/E ratio can be determined simply by gas chromatography after acid hydrolysis of a urine sample, extraction of steroids, and formation of trimethylsilyl derivatives. A timed collection of urine is unnecessary because the ratio of A/E is used rather than absolute values. In men suffering from benign prostate hypertrophy who are treated with Finasteride (a 5 alpha-reductase inhibitor), the A/E ratio decreases to less than 0.5. The A/E ratio decrease can be detected long before there is clinical improvement.

5-alpha Reductase Inhibitors↗

Cytostatic effect of homo-aza-steroidal esters in vivo and in vitro. Structure-activity relationships.

The p-[N,N-bis (2-chloroethyl)amino]phenylacetate esters of 3 beta-hydroxy-N-methyl-17 alpha-aza-D-homo-5 alpha-androstan-17-one and 3 beta-hydroxy-17 alpha-aza-D-homo-5 alpha-androstane have been prepared and their antitumor activity evaluated against L1210 leukemia, P388 leukemia, Ehrlich ascites tumor (EAT) and Lewis Lung Carcinoma (LLC). The results are compared with those of the p-[N,N-bis (2-chloroethyl)amino]phenylacetate of 3 beta-hydroxy-17 alpha-aza-D-homo- 5 alpha-androstan-17-one. The above compounds were also tested in vitro against L1210, P 388, EAT and BHX cell cultures. All compounds were found to be active and their structure-activity relationship is discussed.

Androstanes↗

Dutasteride: a new 5-alpha reductase inhibitor for men with lower urinary tract symptoms secondary to benign prostatic hyperplasia.

Dutasteride is a new 5-alpha reductase inhibitor for the treatment of men with moderate to severe lower urinary tract symptoms secondary to benign prostatic hyperplasia. It has been available in the UK since March 2003. It is a competitive inhibitor of both type I and type II isoforms of the 5-alpha reductase enzyme that converts testosterone to the more potent androgen, dihydrotestosterone. Randomised controlled studies have shown dutasteride to be statistically more effective than placebo in reducing lower urinary tract symptoms and increasing maximum urinary flow rates. This is a consequence of a reduction in serum dihydrotestosterone and hormone dependent prostate volume. Dutasteride has also been shown to decrease the absolute risk of urinary retention and the need for prostate-related surgery when compared to placebo taken over a 24-month period. In this review article we discuss the pharmacology and clinical effects of dutasteride, a new dual-acting 5-alpha reductase inhibitor.

5-alpha Reductase Inhibitors↗

Hair loss remedies--separating fact from fiction.

Hair loss is a common complaint in the outpatient setting. Frequently, patients conduct their own research on hair loss diagnosis and treatment and are faced with a number of manufacturers' claims that their products will benefit hair loss. This paper explores the truth behind those claims of hair regrowth. We intend for this information to serve as a "consumer report" for healthcare providers and patients and to help separate some of the valid claims for hair regrowth from those that are purely fiction.

Alopecia↗

A current review of medical therapy for benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) is one of the most common diseases of aging men. It is estimated that by age 60 years, greater than 50% of men will have histologically documented evidence of the disease. Therapy for this disease has evolved considerably from its inception. Recent data from long-term population-based studies have shed new light on the treatment of this common problem in aging men. The authors review the current state of diagnosis of BPH and medical therapy for this condition in the primary care setting.

Adrenergic alpha-Antagonists↗

[Dutasteride (Avodart): a novel 5-alpha reductase inhibitor for treatment of benign prostate hypertrophy].

Dutasteride (Avodart), a novel dual 5-alpha reductase inhibitor is effective for the treatment of benign prostate hypertrophy, of more than 30 cc because the reduction of the level of dihydrotestosterone. By reducing prostatic volume, dutasteride improves moderate to severe symptoms and flow rate. It allows a reduction of disease progression by reducing the rate of acute urinary retention and need for surgery.

Azasteroids↗

Effective treatment of female androgenic alopecia with dutasteride.

Dihydrotestosterone is the main molecule responsible for androgenic alopecia. Finasteride, which reduces transformation of testosterone into dihydrotestosterone and decreases dihydrotestosterone activity, is approved for treatment of androgenic alopecia in men. We describe the case of a 46-year-old woman with androgenic alopecia, non-responsive to minoxidil, who initially benefited from finasteride. Due to only limited improvement after finasteride and persisting profound psychological distress resulting from androgenic alopecia, another 5-reductase inhibitor, dutasteride, was introduced. Clinical evaluation and trichogram were applied for assessment of dutasteride efficacy in this patient. Additionally, mean hair diameter was monitored by means of computer dermoscopy. After 6 months of therapy, significant improvement was observed and after 9 months the clinical diagnosis of androgenic alopecia could no longer be made in this patient. No side effects were observed. In conclusion, theoretical data and our experience in this case show that dutasteride might develop into a true alternative in treatment of androgenic alopecia.

5-alpha Reductase Inhibitors↗

[Effect of dutasteride on reduction of intraoperative bleeding related to transurethral resection of the prostate].

OBJECTIVE: The pharmacological action of 5-alpha-reductase inhibitors (5-ARI) would reduce angiogenesis associated with benign prostatic hyperplasia (BPH), thereby decreasing peroperative bleeding during transurethral resection of the prostate (TURP). Dutasteride, a double inhibitor of 5-alpha-reductase iso-enzymes types 1 and 2, was not been previously studied in the context of reduction of peroperative bleeding related to TURP. MATERIAL AND METHODS: We conducted a multicentre, randomized, double-blind, placebo-controlled, parallel group study to evaluate the efficacy of dutasteride 0.5 mg per day, in peroperative bleeding related to TURP for BPH in patients over the age of 50 years with a prostatic volume greater than 30 cm3. Treatment was administered for 4 weeks before the operation. The primary endpoint was haemoglobin, expressed in grams, and expressed in relation to the weight of prostate resected, also expressed in grams. RESULTS: 59 patients were evaluated (32 treated with dutasteride and 27 treated with placebo). A significant difference in peroperative bleeding was observed between the dutasteride group (1.944 +/- 1.816 g of Hb/g of prostate resected) and the placebo group (1.401 +/- 1.021 g of Hb/g of prostate resected). Preoperative treatment was well tolerated. CONCLUSION: The working hypothesis of the study was not confirmed due to the low bleeding rate in the placebo group and the results suggest that a longer duration of treatment with dutasteride would reduce intraoperative and postoperative bleeding in TURP.

Aged↗

[Effect of dutasteride on reduction of plasma DHT following finasteride therapy in patients with benign prostatic hyperplasia].

INTRODUCTION: Dihydrotestosterone (DHT) is a steroid hormone derived from testosterone, by the action of two distinct isoenzymes (type 1 and 2) of 5-alpha-reductase. Dutasteride is a specific selective inhibitor of the two isoenzymes, while finasteride is a selective inhibitor of type 2 -alpha-reductase. The working hypothesis is that the double 5-alpha-reductase inhibition induced by dutasteride therapy for 6 weeks should induce a supplementary reduction of plasma DHT levels compared to a parallel patient group continuing finasteride therapy over the same period. MATERIALS AND METHODS: In this prospective, two-centre, double-blind study, 21 patients previously treated by finasteride 5 mg for benign prostatic hyperplasia (BPH) for at least 6 months were randomized to receive either dutasteride 0.5 mg, or finasteride 5 mg daily for 6 weeks. RESULTS: The mean relative variation of plasma DHT was 67.3% +/- 16.16% in the dutasteride group and 30.3% +/- 59.8% in the finasteride group. The reduction of DHT was numerically greater and more constant in the dutasteride group than in the finasteride group at 6 weeks; such a tendency was already observed after two weeks of treatment with dutasteride. Nevertheless, these differences were not statistically significant. Both medications were well tolerated and the only treatment-related adverse event (epigastric pain) was reported in the finasteride group. CONCLUSIONS: The working hypothesis was therefore not statistically confirmed. It is difficult to conclude whether this reflects poor patient compliance with long-term finasteride for BPH or variability of response in patients with good compliance with treatment.

Aged↗

NSC 290205-based therapy in murine pancreatic adenocarcinoma PAN02 in combination with adriamycin (ADR).

BACKGROUND: NSC 290205 (A) is a hybrid synthetic antitumor ester, which combines a D-lactam derivative of androsterone and nitrogen mustard. In this study, the antitumor activity of A in combination with ADR (AHOP) was investigated in comparison with the standard CHOP regimen. MATERIALS AND METHODS: PAN02 adenocarcinoma was used in this study. C57Bl mice were used for chemotherapy evaluation. The activity was assessed from the inhibition of tumor growth and the oncostatic parameter T/C%. RESULTS: Treatment with A or cyclophosphamide produced almost equal borderline activity. Moreover, both the CHOP and AHOP regimens showed significant and comparable antitumor effects. AHOP caused the maximum effect, inhibiting tumor growth by 56.8%. CHOP was less effective, producing 47.7% tumor inhibition. CONCLUSION: It is very likely that the D-lactamic steroid (androstan) alkylator forA, containing the amide group -NH-CO-, combined with ADR which intercalates between DNA base-pairs, is the explanation for the higher activity of AHOP as compared to CHOP.

Animals↗