164656-23-9

White Crystalline Solid

antihypertensive, ACE inhiibitor

Dutasteride is a dual inhibitor of 5α-reductase isoenzymes type 1 and 2; structurally related to Finasteride (F342000). Dutasteride is used in the treatment of benign prostatic hyperplasia.

Used in the treatment of benign prostatic hyperplasia. Dual inhibitor of 5a-reductase isoenzymes type 1 and 2; structurally related to Finasteride.

Used in the treatment of benign prostatic hyperplasia. Dual inhibitor of 5α-reductase isoenzymes type 1 and 2; structurally related to Finasteride.

ChEBI: Finasteride in which the tert-butyl group is replaced by a 2,5-bis(trifluoromethyl)phenyl group. A synthetic 4-azasteroid, dutasteride is a selective inhibitor of both the type 1 and type 2 isoforms of steroid 5alpha-reductase an intracellular enzyme that converts testosterone to 5alpha-dihydrotestosterone. Dutasteride is used for the treatment of symptomatic benign prostatic hyperplasia in men with an enlarged prostate gland.

Dutasteride was launched for the symptomatic treatment of benign prostatic hyperplasia. Dutasteride can be prepared from 3-oxo-4-androstene-17β-carboxylic acid by several ways in 6 or 8 steps. Dutasteride is a dual inhibitor of type 1 and 2 isoforms of 5α-reductase unlike finasteride, the first marketed 5α-reductase inhibitor, which only acts on type 2 isozyme. Dutasteride is a 3-fold greater inhibitor of type-2 5α-reductase than finasteride in men and has greater effect on the type-l than on type-2 isozyme. In animal models,dutasteride exhibited superior efficacy and pharmacokinetics compared to finasteride. In patients with benign prostate hyperplasia, administration of dutasteride was shown to dose-dependently decrease serum dihydrotestosterone levels with greater efficacy as compared to finasteride (95% vs 67%). Serum testosterone levels increased with both active drugs, in conjunction with dihydrotestosterone suppression but remained within normal ranges. In long term studies, in men with moderate to severe benign prostate hyperplasia, once daily dutasteride significantly reduced prostate volume, reduced the risk of acute urinary retention and surgery by 57% and improved lower urinary tract symptoms and urinary flow measurements. After oral administration, dutasteride is rapidly absorbed, has a short distribution phase and a mean bioavailability of 60%. The high volume of distribution, combined with its low linear clearance results in a prolonged dose dependent half-life (from 3 days at low concentrations to 5 weeks at high concentrations) whereas finasteride’s half-life time is approximately 10 h. Dutasteride is well tolerated and the most occurring adverse events are impotence, decrease in libido, ejaculation disorders and gynaecomastia. Unlike a-blockers which primarily act acutely on benign prostatic hyperplasia symptoms, 5a-reductase inhibitors can alter disease progression. Concomitant administration of dutasteride did not affect the pharmacokinetics of either tamsulosin or terazosin. In addition, the tolerability of both terazosin and tamsulosin were improved during combination therapy.

GlaxoSmithKline (UK)

Avodart (GlaxoSmithKline).

Similar to finasteride, dutasteride is a competitive and mechanism-based inhibitor not only of type 2 but also of type 1 5α-reductase isoenzymes, with which stable enzyme-NADP adduct complexes are formed, inhibiting the conversion of testosterone to DHT. The suppression of both type 1 and type 2 isoforms results in greater and more consistent reduction of plasma DHT than that observed for finasteride. The more effective dual inhibition of type 1 and type 2 5α-reductase isoforms lowers circulating DHT to a greater extent than with finasteride and shows advantages in treating BPH and other disease states (e.g., prostate cancer) that are DHT-dependent.

Dutasteride is a potent dual inhibitor of 5α-reductase isoenzymes types 1 and 2 (IC50 = 6 nM 5-AR1; 7 nM 5-AR2). Dutasteride blocks testosterone conversion to dihydrotesterone, and is used clinically for treating benign prostatic hyperplasia (BPH).

The maximum effect of 0.5 mg daily doses of dutasteride on the suppression of DHT is dose-dependent and is observed within 1 to 2 weeks. After 2 weeks of 0.5 mg daily dosing, median plasma DHT concentrations were reduced by 90%, and after 1 year, the median decrease in plasma DHT was 94%. The median increase in plasma testosterone was 19% but remained within the physiological range. The drug also reduced serum prostatic specific antigen by approximately 50% at 6 months and total prostate volume by 25% at 2 years. Dutasteride produced improvements in quality of life and peak urinary flow rate and reduction of acute urinary retention without the need for surgery.

Testosterone-5-alpha-reductase inhibitor:
Benign prostatic hyperplasia

The main side effects are ED, decreased libido, gynecomastia, and ejaculation disorders. Long-term use (>4 years), however, did not reveal increased onset of sexual side effects. In addition, the combination of dutasteride and tamsulosin is well-tolerated and has the added advantage of rapid symptomatic relief.

Dutasteride can be prepared from 3-oxo-4-androstene-17β-carboxylic acid by several ways in 6 or 8 steps. In the preparation of dutasteride, the introduction of the carbon-carbon double bond in conjugation with C-3 carbonyl carbon of azaandrosteriods is one of the most important chemical reaction.
an efficient synthesis of dutasteride: utilizing benzoyl group as novel lactamic protecting group

dutasteride, which inhibits both 5αr1/5αr2, is efficacious in blocking prostate cancer development or progression in c57bl/6 tramp x fvb mice [2].

Potentially hazardous interactions with other drugs
None known

Dutasteride is metabolised by the cytochrome P450 isoenzymes CYP3A4 and CYP3A5, and most of a dose is excreted as metabolites in the faeces.

Store at -20°C

The American FDA approved a 2-year multicenter randomized double-blind control clinical trial – the first long term clinical assessment of the combined usage of Dutasteride and α receptor blockers. Included subjects were male patients with moderate to severe prostate enlargement (ages greater than or equal to 50, prostate volume (PV) ≥30 cc, serum prostate specific antigen (PSA) levels 1.5-10ng/ml, 5ml/sec < maximum urinary flow (Qmax) ≤15ml/sec, minimum urination ≥ 125ml, international prostate symptom score (IPSS) ≥ 12). Patients were first given a placebo for 4 weeks and then were randomly given either 0.5mg/day of Dutasteride and 0.4mg/day of Tamsulosin, only 0.5mg/day of Dutasteride, or only 0.4mg/day of Tamsulosin.
Results showed: After 12-24 months, the combined usage of Dutasteride with Tamsulosin had better curative effects than did individual usage.

The human body contains type I and type II 5α reductase, with type II found mainly in the prostate, and type I found mainly in the liver and skin. 5α reductase is the main cause for continuous benign prostate enlargement; it promotes the transformation of testosterone in patients’ prostate into the more active dihydrotestosterone, thus causing prostate cells to enlarge and the prostate to swell. Dutasteride can inhibit both type I and II 5α reductase at the same time. This type of simultaneous inhibiting mechanism can rapidly and continuously reduce prostate size, dramatically improve urination, and reduce the risk fo acute urinary retention and its related prostate surgeries.

[1] schmidt lj1, murillo h, tindall dj. gene expression in prostate cancer cells treated with the dual 5 alpha-reductase inhibitor dutasteride. j androl. 2004 nov-dec;25(6):944-53.
[2] opoku-acheampong ab1, unis d, henningson jn, beck ap, lindshield bl.preventive and therapeutic efficacy of finasteride and dutasteride in tramp mice. plos one. 2013 oct 18;8(10):e77738. doi: 10.1371/journal.pone.0077738. ecollection 2013.