Finasteride

3.03

3.03

Slightly soluble

Freely sol in chloroform, DMSO, ethanol, methanol, n-propanol; sparingly sol in propylene glycol, polyethylene glycol 400; very slightly sol in 0.1N hydrogen chloride, 0.1N sodium hydroxide, water.

1.98e-03 g/L

52.8 [ug/mL] (The mean of the results at pH 7.4)

FDA approved drugs -> Active ingredient

FDA approved drugs -> Active ingredient

252-254 °C

252-254 °C

252 - 254 °C

198.1 Ų [M-H]- [CCS Type: DT; Buffer gas: N2; Ionization: ESI-; Dataset: TOXCAST; Source Identifier: DTXSID3020625]

200 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

199.24 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

Danger

H302 (99.1%): Harmful if swallowed [Warning Acute toxicity, oral]

P203, P260, P264, P270, P273, P280, P301+P317, P318, P319, P330, P391, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 110 reports by companies from 16 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

Finasteride has been associated with a low rate of serum aminotransferase elevations that, in controlled trials, was no higher than with placebo therapy. These elevations were transient and rarely required dose modification, and have occurred with both the 5 mg dose for prostatic hypertrophy and the 1 mg dose for hair growth. There have been published reports of transient serum enzyme elevations occurring during finasteride therapy, but none of clinically apparent liver injury.

Common adverse finasteride-related adverse effects include loss of libido, erectile dysfunction (2% to 4%), decreased ejaculatory volume, and gynecomastia. Finasteride is also associated with orthostatic hypotension, particularly right after initiating therapy. This adverse event can be additive in patients who are taking concomitant alpha-blockers.

Single doses up to 400 mg and multiple dosages up to 80 mg daily for 3 months are well-tolerated and have not resulted in significant adverse reactions in clinical studies. Until further data is obtained, no specific treatment for an overdose of finasteride can be recommended.

The mechanism of action of Finasteride is based on its preferential inhibition of Type II 5a-reductase through the formation of a stable complex with the enzyme. Inhibition of Type II 5a-reductase blocks the peripheral conversion of testosterone to DHT, resulting in significant decreases in serum and tissue DHT concentrations, minimal to moderate increase in serum testosterone concentrations, and substantial increases in prostatic testosterone concetrations. As DHT appears to be the principal androgen responsible for stimulation of prostatic growth, a decrease in DHT concentrations will result in a decrease in prostatic volume (approximately 20-30% after 6-24 months of continued therapy). In men with androgenic alopecia, the mechanism of action has not been fully determined, but finasteride has shown to decrease scalp DHT concentration to the levels found in hairy scalp, reduce serum DHT, increase hair regrowth, and slow hair loss.

Finasteride (Proscar, an orally active 5 alpha-reductase enzyme inhibitor) blocks the conversion of testosterone to dihydrotestosterone. The effects of finasteride in patients with benign prostatic hyperplasia were investigated in 2 double blind, placebo controlled studies. In study 1, 86 patients were treated with placebo or finasteride (5 to 80 mg/day) for 12 wk, followed by a 12 wk drug free period. After 12 wk of treatment all doses of finasteride showed significant decreases in prostate volume. However, 12 wk after discontinuation of finasteride prostate volume returned to near baseline values. In study 2, 104 patients were treated with placebo or finasteride (0.2 to 40 mg/day) for 24 wk. After 24 wk of finasteride treatment prostate volume showed a mean decrease of 24% and 28% (p less than 0.01) in the 1 and 5 mg groups, respectively. Lower doses had a lesser effect on prostate shrinkage. Maximum urinary flow showed a mean increase of 3.7 cc/second when the 1 and 5 mg groups were combined. Symptom improvement was observed in the 1 and 5 mg groups, although this was not statistically different from the placebo group due to the small sample size.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Finasteride

vLess-DILI-concern

0

No match

DOI:10.1016/j.drudis.2016.02.015

A series of studies was conducted to determine the developmental toxicity of the 5 alpha-reductase inhibitor finasteride (MK-0906) in rats. This compound was administered orally once daily to pregnant rats during various extended treatment periods during gestation. F1 offspring were evaluated on day 20 of gestation as well as postnatally through mating to produce an F2 generation. MK-0906 treatment induced dosage related incidences of hypospadias (penischisis) in male offspring with a threshold dosage level near 0.1 mg/kg/day and a 100% effect level of 100 mg/kg/day (with dosing through Day 20 of gestation). MK-0906 also caused decreased anogenital distance in male offspring. The dosage response for this effect (ranging from a 4.2% decrease at 0.003 mg/kg/day to a 38% decrease at 100 mg/kg/day) was more shallow than that for hypospadias. The decreases in anogenital distance were at least partially reversible postnatally with essentially complete recovery at dosages up to 0.1 mg/kg/day. There was also a dosage-related, temporary induction of nipples in F1 males. All of these effects were apparent following treatment on Days 6 through 17 of gestation but were more pronounced when dosing extended to Day 20 of gestation. Slight maternal toxicity consisting of minor decreases in body weight gain occurred only at dosages of 3 mg/kg/day and higher, indicating the selective nature of the developmental toxicity. The 5 alpha-reductase enzyme located in the rat fetal genital tubercle was studied in vitro and compared to that in the adult ventral prostate. The values for Km, Vmax, and IC50 for inhibition by MK-0906 were similar in the two tissues.

The endocrine control of descent of the testis in mammalian species is poorly understood. The androgen dependency of testicular descent was studied in the rat using an antiandrogen (flutamide) and an inhibitor of the enzyme 5 alpha-reductase (finasteride). Androgen receptor blockade inhibited testicular descent more effectively than inhibition of 5 alpha-reductase activity. Moreover, its inhibitory effect was limited to the outgrowth phase of the gubernaculum testis, particularly the earliest stages of outgrowth. Gubernacular size was also significantly reduced in fetuses exposed to flutamide during the outgrowth period. In contrast, androgen receptor blockade or 5 alpha-reductase inhibition applied after the initiation of gubernacular outgrowth or during the regression phase did not affect testicular descent. Successful inhibition of the development of epididymis and vas by prenatal flutamide did not correlate with ipsilateral testicular maldescent, suggesting that an intact epididymis is not required for descent of the testis.

Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

G04CB01

D - Dermatologicals

G - Genito urinary system and sex hormones

QG - Genito urinary system and sex hormones

QD - Dermatologicals

Finasteride is an antiandrogenic compound that works by suppressing the production of serum and intraprostatic dihydrotestosterone (DHT) in men via inhibiting the enzyme responsible for the biosynthesis of DHT. The maximum effect of a rapid reduction in serum DHT concentration is expected to be observed 8 hours following administration of the first dose. In a single man receiving a single oral dose of 5 mg finasteride for up to 4 years, there was a reduction in the serum DHT concentrations by approximately 70% and the median circulating level of testosterone increased by approximately 10-20% within the physiologic range. In a double-blind, placebo-controlled study, finasteride reduced intraprostatic DHT level by 91.4% but finasteride is not expected to decrease the DHT levels to castrate levels since circulating testosterone is also converted to DHT by the type 1 isoenzyme expressed in other tissues. It is expected that DHT levels return to normal within 14 days upon discontinuation of the drug. In a study of male patients with benign prostatic hyperplasia prior to prostatectomy, the treatment with finasteride resulted in an approximate 80% lower DHT content was measured in prostatic tissue removed at surgery compared to placebo. While finasteride reduces the size of the prostate gland by 20%, this may not correlate well with improvement in symptoms. The effects of finasteride are reported to be more pronounced in male patients with enlarged prostates (>25 mL) who are at the greatest risk of disease progression. In phase III clinical studies, oral administration of finasteride in male patients with male pattern hair loss promoted hair growth and prevented further hair loss by 66% and 83% of the subjects, respectively, which lasted during two years' treatment. The incidences of these effects in treatment groups were significantly higher than that of the group receiving a placebo. Following finasteride administration, the levels of DHT in the scalp skin was shown to be reduced by more than 60%, indicating that the DHT found in scalp is derived from both local DHT production and circulating DHT. The effect of finasteride on scalp DHT is likely seen because of its effect on both local follicular DHT levels as well as serum DHT levels.. There is evidence from early clinical observations and controlled studies that finasteride may reduce bleeding of prostatic origin.

Finasteride acts as a competitive and specific inhibitor of Type II 5α-reductase, a nuclear-bound steroid intracellular enzyme primarily located in the prostatic stromal cell that converts the androgen testosterone into the more active metabolite, 5α-dihydrotestosterone (DHT). DHT is considered to be the primary androgen playing a role in the development and enlargement of the prostate gland. It serves as the hormonal mediator for the hyperplasia upon accumulation within the prostate gland. DHT displays a higher affinity towards androgen receptors in the prostate gland compared to testosterone and by acting on the androgen receptors, DHT modulates genes that are responsible for cell proliferation. Responsible for the production of DHT together with type I 5α-reductase, the type II 5α-reductase isozyme is primarily found in the prostate, seminal vesicles, epididymides, and hair follicles as well as liver. Although finasteride is 100-fold more selective for type II 5α-reductase than for the type I isoenzyme, chronic treatment with this drug may have some effect on type I 5α-reductase, which is predominantly expressed in sebaceous glands of most regions of skin, including the scalp, and liver. It is proposed that the type I 5α-reductase and type II 5α-reductase is responsible for the production of one-third and two-thirds of circulating DHT, respectively. The mechanism of action of Finasteride is based on its preferential inhibition of Type II 5α-reductase through the formation of a stable complex with the enzyme _in vitro_ and _in vivo_. Finasteride works selectively, where it preferentially displays a 100-fold selectivity for the human Type II 5α-reductase over type I enzyme. Inhibition of Type II 5α-reductase blocks the peripheral conversion of testosterone to DHT, resulting in significant decreases in serum and tissue DHT concentrations, minimal to moderate increase in serum testosterone concentrations, and substantial increases in prostatic testosterone concentrations. As DHT appears to be the principal androgen responsible for stimulation of prostatic growth, a decrease in DHT concentrations will result in a decrease in prostatic volume (approximately 20-30% after 6-24 months of continued therapy). It is suggested that increased levels of DHT can lead to potentiated transcription of prostaglandin D2, which promotes the proliferation of prostate cancer cells. In men with androgenic alopecia, the mechanism of action has not been fully determined, but finasteride has shown to decrease scalp DHT concentration to the levels found in the hairy scalp, reduce serum DHT, increase hair regrowth, and slow hair loss. Another study suggests that finasteride may work to reduce bleeding of prostatic origin by inhibiting vascular endothelial growth factor (VEGF) in the prostate, leading to atrophy and programmed cell death. This may bestow the drug therapeutic benefits in patients idiopathic prostatic bleeding, bleeding during anticoagulation, or bleeding after instrumentation.

Finasteride undergoes extensive hepatic metabolism predominantly mediated by the cytochrome P450 3A4 (CYP3A4) enzyme to form the t-butyl side chain monohydroxylated and monocarboxylic acid metabolites. Theses metabolites retain less than 20% of the pharmacological activity of the parent compound.

Finasteride has known human metabolites that include N-(1-Hydroxy-2-methylpropan-2-yl)-9a,11a-dimethyl-7-oxo-1,2,3,3a,3b,4,5,5a,6,9b,10,11-dodecahydroindeno[5,4-f]quinoline-1-carboxamide.

Drug is extensively metabolized, primarily in the liver via CYP3A4. Two metabolites have been identified with дЉ_20% of the activity of finasteride. Route of Elimination: Following an oral dose of 14C-finasteride in man (n = 6), a mean of 39% (range, 32 to 46%) of the dose was excreted in the urine in the form of metabolites; 57% (range, 51 to 64%) was excreted in the feces. Urinary excretion of metabolites was decreased in patients with renal impairment. This decrease was associated with an increase in fecal excretion of metabolites. Half Life: 4.5 hours (range 3.3-13.4 hours)

57GNO57U7G

FINASTERIDE

Established Pharmacologic Class [EPC] - 5-alpha Reductase Inhibitor

Mechanisms of Action [MoA] - 5-alpha Reductase Inhibitors

Finasteride is a 5-alpha Reductase Inhibitor. The mechanism of action of finasteride is as a 5-alpha Reductase Inhibitor.

FINASTERIDE

Drugs that inhibit 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE. They are commonly used to reduce the production of DIHYDROTESTOSTERONE.

Drugs used in the treatment of urological conditions and diseases such as URINARY INCONTINENCE and URINARY TRACT INFECTIONS.

Finasteride is well absorbed following oral administration and displays a slow accumulation phase after multiple dosing.[lablel] In healthy male subjects receiving oral finasteride, the mean oral bioavailability was 65% for 1 mg finasteride and 63% for 5 mg finasteride, and the values ranged from 26 to 170% for 1 mg dose and from 34 to 108% for 5 mg dose, respectively. It is reported that food intake does not affect the oral bioavailability of the drug. The peak plasma concentrations (Cmax) averaged 37 ng/mL (range, 27-49 ng/mL) and was reached 1-2 hours post administration. The AUC(0-24 hr) was 53 ngxhr/mL (range, 20-154 ngxhr/mL). The plasma concentrations and AUC are reported to be higher in elderly male patients aged 70 years or older.

In healthy subjects, about 32-46% of total oral dose of finasteride was excreted in the urine in the form of metabolites while about 51-64% of the dose was excreted in the feces. In patients with renal impairment, the extent of urinary excretion of finasteride is expected to be decreased while the fecal excretion is increased.

The volume of distribution is 76 L at steady state, ranging from 44 to 96 L. Finasteride has been shown to cross the blood brain barrier but does not appear to distribute preferentially to the CSF. It is not known whether finasteride is excreted in human milk.

In healthy young subjects (n=15), the mean plasma clearance of finasteride was 165 mL/min with the range between 70 and 279 mL/min.

Medication: Treatment of benign prostatic hypertrophy

MEDICATION

Use (kg; approx.) in Germany (2009): >250

For the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to: Improve symptoms, reduce the risk of acute urinary retention, reduce the risk of the need for surgery including transurethral resection of the prostate. Also used for the stimulation of regrowth of hair in men with mild to moderate androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness).