Tamsulosin
Encyclopedia
Tamsulosin (icon or t) is an α1a-selective alpha blocker
used in the symptomatic treatment of benign prostatic hyperplasia
(BPH). Tamsulosin was developed by Yamanouchi Pharmaceuticals (now part of Astellas Pharma
) and is marketed by various companies under licence, including Boehringer-Ingelheim
and CSL
. Tamsulosin hydrochloride extended-release capsules are marketed under the trade name
s Flomax, Flomaxtra, Contiflo XL, and Urimax, though generic non-modified release capsules are still approved and marketed in many countries, such as Canada. In Colombia (South America) it is marketed under Uripur from Laboratorios Bussié, beside it is marketed under Harnal D in some places. The U.S. patent for Flomax expired in October 2009. The U.S. Food and Drug Administration (FDA) approved generic Flomax in March 2010.
In Egypt Italy and Iceland it is marketed under the trade Omnic by Astellas Pharma Europe.
that has preferential selectivity for the α1A receptor
in the prostate versus the α1B receptor
in the blood vessels.
, but is sometimes used for the passage of kidney stone
s by the same mechanism of smooth muscle relaxation via alpha antagonism.
Tamsulosin has also affected the sexual function in men. Tamsulosin can cause males to experience retrograde ejaculation
. In males, retrograde ejaculation occurs when the fluid to be ejaculated, which would normally exit the body via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts and the ejaculate goes to the urethra, the area of least pressure. In retrograde ejaculation, this sphincter does not function properly.
Occasionally, tamsulosin can cause a drop in blood pressure, rarely resulting in dizziness or fainting. Other reported side effects include headache, dizziness, nasal congestion, and palpitations.
effects of other alpha-blockers such as doxazosin
and terazosin
.
and Tamsulosin) trial have recently demonstrated that treatment with the combination of Avodart and tamsulosin provides greater symptom benefits compared with either monotherapy for treatment of benign prostatic hyperplasia.
Alpha blocker
Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
used in the symptomatic treatment of benign prostatic hyperplasia
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....
(BPH). Tamsulosin was developed by Yamanouchi Pharmaceuticals (now part of Astellas Pharma
Astellas Pharma
is a Japanese pharmaceutical company, formed on 1 April 2005 from the merger of and .Astellas' franchise areas are urology, immunology , dermatology, cardiology, and infectious disease...
) and is marketed by various companies under licence, including Boehringer-Ingelheim
Boehringer-Ingelheim
C.H. Boehringer Sohn AG & Ko. KG is the parent company of Boehringer Ingelheim, which was founded in 1885 by Albert Boehringer in Ingelheim am Rhein. The Boehringer Ingelheim group is one of the world's 20 leading pharmaceutical companies. Headquartered in Ingelheim, Germany, it operates globally...
and CSL
CSL Limited
CSL Limited is a global specialty biopharmaceutical company that researches, develops, manufactures and markets products to treat and prevent serious human medical conditions...
. Tamsulosin hydrochloride extended-release capsules are marketed under the trade name
Trade name
A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....
s Flomax, Flomaxtra, Contiflo XL, and Urimax, though generic non-modified release capsules are still approved and marketed in many countries, such as Canada. In Colombia (South America) it is marketed under Uripur from Laboratorios Bussié, beside it is marketed under Harnal D in some places. The U.S. patent for Flomax expired in October 2009. The U.S. Food and Drug Administration (FDA) approved generic Flomax in March 2010.
In Egypt Italy and Iceland it is marketed under the trade Omnic by Astellas Pharma Europe.
Mechanism
Tamsulosin is a selective α1 receptor antagonistReceptor 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...
that has preferential selectivity for the α1A receptor
Alpha-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:...
in the prostate versus the α1B receptor
Alpha-1B adrenergic receptor
The alpha-1B adrenergic receptor , also known as ADRA1B, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.-Interactions:...
in the blood vessels.
Clinical uses
Tamsulosin is primarily used for benign prostatic hyperplasiaBenign 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....
, but is sometimes used for the passage of kidney stone
Kidney stone
A kidney stone, also known as a renal calculus is a solid concretion or crystal aggregation formed in the kidneys from dietary minerals in the urine...
s by the same mechanism of smooth muscle relaxation via alpha antagonism.
Adverse effects
Two ADRs (Adverse Drug Reactions) have been reported:- Immunologic: It contains a sulfaSULFASULFA, short for Surrendered ULFA, i.e. members of the United Liberation Front of Asom that surrendered to the government.Beginning with 1990, the Government of India has attempted to wean away members of ULFA. In 1992 a large section of second rank leaders and members surrendered to government...
moiety, thus causing typical reactions to sulfa drugs. - Ophthalmologic: Patients taking tamsulosin are prone to a complicationComplication (medicine)Complication, in medicine, is an unfavorable evolution of a disease, a health condition or a medical treatment. The disease can become worse in its severity or show a higher number of signs, symptoms or new pathological changes, become widespread throughout the body or affect other organ systems. A...
known as floppy iris syndromeIntraoperative floppy iris syndromeIntraoperative floppy iris syndrome is a complication that may occur during cataract extraction in certain patients. This syndrome is characterized by a flaccid iris which billows in response to ordinary intraocular fluid currents, a propensity for this floppy iris to prolapse towards the area of...
during cataract surgeryCataract surgeryCataract surgery is the removal of the natural lens of the eye that has developed an opacification, which is referred to as a cataract. Metabolic changes of the crystalline lens fibers over time lead to the development of the cataract and loss of transparency, causing impairment or loss of vision...
. Adverse outcomes of the surgery are greatly reduced by the surgeon's prior knowledge of the patient's history with this drug, and thus having the option of alternative techniques.
Tamsulosin has also affected the sexual function in men. Tamsulosin can cause males to experience retrograde ejaculation
Retrograde ejaculation
In the human male reproductive system, retrograde ejaculation occurs when semen, which would normally be ejaculated via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation forcing the semen to exit via the urethra, the path of least...
. In males, retrograde ejaculation occurs when the fluid to be ejaculated, which would normally exit the body via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts and the ejaculate goes to the urethra, the area of least pressure. In retrograde ejaculation, this sphincter does not function properly.
Occasionally, tamsulosin can cause a drop in blood pressure, rarely resulting in dizziness or fainting. Other reported side effects include headache, dizziness, nasal congestion, and palpitations.
Clinical comparison
Although prostate specific, it does not have the prostate apoptoticApoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
effects of other alpha-blockers such as doxazosin
Doxazosin
Doxazosin mesylate, a quinazoline compound sold by Pfizer under the brand names Cardura and Carduran, is an α1a-selective alpha blocker used to treat high blood pressure and urinary retention associated with benign prostatic hyperplasia ....
and terazosin
Terazosin
Terazosin is a selective alpha 1 antagonist used for treatment of symptoms of an enlarged prostate...
.
Use in combination therapy
The results of the CombAT (Combination of AvodartDutasteride
Dutasteride is a dual 5-a reductase inhibitor that inhibits conversion of testosterone to dihydrotestosterone ....
and Tamsulosin) trial have recently demonstrated that treatment with the combination of Avodart and tamsulosin provides greater symptom benefits compared with either monotherapy for treatment of benign prostatic hyperplasia.
External links
- Tamsulosin – information from USP DI Advice for the Patient
- Flomax (drugs.com) – U.S. product information
- Product label U.S. Food and Drug Administration (FDA)
- Flomax (Official Site) – Official Site