Silodosin
Encyclopedia
Silodosin is a medication for the symptomatic treatment of benign prostatic hyperplasia
. It acts as an α1-adrenoceptor antagonist
with high uroselectivity (selectivity for the prostate
).
Kissei licensed the US, Canadian, and Mexican rights for silodosin to Watson Pharmaceuticals, Inc. in 2004.
On February 12, 2008, Watson announced that the New Drug Application submitted to the United States
Food and Drug Administration
for silodosin has been accepted for filing. FDA approved this drug on October 9th, 2008. Silodosin is marketed under the trade names Rapaflo in the US and Silodyx in Europe. and Rapilif in India (Ipca Urosciences)
adrenergic receptor, it causes practically no orthostatic hypotension
(in contrast to other α1 blockers). On the other side, the high selectivity seems to cause more problems with ejaculation
.
As α1A adrenoceptor antagonists are being investigated as a means to male birth control due to their ability to inhibit ejaculation but not orgasm, a trial with 15 male volunteers was conducted. While silodosin was completely efficacious in preventing the release of semen in all subjects, 12 out of the 15 patients reported mild discomfort upon orgasm. The men also reported the psychosexual side effect of being strongly dissatisfied by their lack of ejaculation.
Benign prostatic hyperplasia
Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....
. It acts as an α1-adrenoceptor antagonist
Receptor antagonist
A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
with high uroselectivity (selectivity for the prostate
Prostate
The prostate is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals....
).
History
Silodosin received its first marketing approval in Japan in May 2006 under the tradename Urief, which is jointly marketed by Kissei Pharmaceutical Co., Ltd. and Daiichi Sankyo Pharmaceutical Co., Ltd.Kissei licensed the US, Canadian, and Mexican rights for silodosin to Watson Pharmaceuticals, Inc. in 2004.
On February 12, 2008, Watson announced that the New Drug Application submitted to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
for silodosin has been accepted for filing. FDA approved this drug on October 9th, 2008. Silodosin is marketed under the trade names Rapaflo in the US and Silodyx in Europe. and Rapilif in India (Ipca Urosciences)
Pharmacology
Since silodosin is a highly selective inhibitor of the α1AAlpha-1A adrenergic receptor
The alpha-1A adrenergic receptor , also known as ADRA1A, formerly known as the alpha-1C adrenergic receptor, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.-Agonists:...
adrenergic receptor, it causes practically no orthostatic hypotension
Orthostatic hypotension
Orthostatic hypotension, also known as postural hypotension, orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg, and may be...
(in contrast to other α1 blockers). On the other side, the high selectivity seems to cause more problems with ejaculation
Ejaculation
Ejaculation is the ejecting of semen from the male reproductory tract, and is usually accompanied by orgasm. It is usually the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. In rare cases ejaculation occurs because of prostatic disease...
.
As α1A adrenoceptor antagonists are being investigated as a means to male birth control due to their ability to inhibit ejaculation but not orgasm, a trial with 15 male volunteers was conducted. While silodosin was completely efficacious in preventing the release of semen in all subjects, 12 out of the 15 patients reported mild discomfort upon orgasm. The men also reported the psychosexual side effect of being strongly dissatisfied by their lack of ejaculation.