Description
Tamsulosin hydrochloride is the hydrochloride form of Tamsulosin (Trade name: Alna ® / Flomax ®). It is a kind of medication used for the treatment of symptomatic benign prostatic hyperplasia (BPH), boosting the passage of kidney stones. It can also be used for the treatment of acute urinary retention. It is a kind of selective antagonist of alpha-1A and alpha-1B-adrenoceptros located in prostate, prostatic capsule, prostatic urethra, and bladder neck. The blockage of these receptors through Tamsulosin causes the relaxation of smooth muscles in the bladder neck and prostate.
References
https://www.drugbank.ca/drugs/DB00706
https://en.wikipedia.org/wiki/Tamsulosin
Description
Tamsulosin is a potent antagonist of α
1-adrenergic receptors (α
1-ARs; K
i = 0.229 nM in a radioligand binding assay). It is 3,800-fold selective for α
1-ARs over α
2-ARs (K
i = 871 nM). Tamsulosin antagonizes norepinephrine-induced contraction of isolated rabbit aorta (pA
2 = 10.11) but has no effect on contraction stimulated by histamine, serotonin , angiotensin II , or prostaglandin F
2α .
In vivo, tamsulosin reverses the pressor effect of phenylephrine (Item Nos.
17205 |
18619) in pithed rats. It reversibly reduces fertility in male rats when administered at a dose of 0.15 mg/kg. Tamsulosin (1-100 μg/kg) also reduces prostatic pressure in a dose-dependent manner with minimal hypotensive effects in anesthetized dogs. Formulations containing tamsulosin have been used for the treatment of benign prostatic hyperplasia.
Chemical Properties
White to Off-White Solid
Originator
Contiflo OD,Ranbaxy Laboratories,India
Uses
Specific a1-adrenoceptor antagonist. Used in the treatment of benign prostatic hypertrophy
Uses
An α1-adrenoceptor antagonist
Uses
(R)-Tamsulosin is a specific α1-adrenoceptor antagonist. It is used in the treatment of benign prostatic hypertrophy.
Uses
Specific α1-adrenoceptor antagonist. Used in the treatment of benign prostatic hypertrophy.
Uses
antineoplastic, alkylating agent
Definition
ChEBI: Tamsulosin hydrochloride is a hydrochloride resulting from the reaction of equimolar amounts of tamulosin and hydrogen chloride. It has a role as an alpha-adrenergic antagonist and an antineoplastic agent. It contains a tamsulosin(1+). It is an enantiomer of an ent-tamsulosin hydrochloride.
Manufacturing Process
In 1,000 ml of acetonitrile was suspended 17 g of 5-{2-[2-(2-
ethoxyphenoxy)ethylamino]-1-hydroxy-2-methylethyl}-2-
methoxybenzenesulfonamide hydrochloride and while stirring the suspension,
9 g of thionyl chloride was added dropwise to the suspension at room
temperature, whereby the product first dissolved and then began to crystallize
gradually. After stirring the mixture for two days, the crystals formed were
recovered by filtration, washed with chloroform and dried to provide 15 g of
5-{1-chloro-2-[2-(2-ethoxyphenoxy)ethylamino]-2-methylethyl}-2-
methoxybenzenesulfonamide hydrochloride. Melting point: 197°-200°C.
In methanol was dissolved the 5-{1-chloro-2-[2-(2-
ethoxyphenoxy)ethylamino]ethyl}-2-methoxybenzenesulfonamide
hydrochloride and after adding thereto 10% palladium carbon, dechlorination
was performed under hydrogen stream at normal temperature and pressure.
The palladium carbon was filtered away and the filtrate was concentrated
under reduced pressure to provide the 2-methoxy-5-{2-[2-(2-
ethoxyphenoxy)ethylamino]ethyl}benzenesulfonamide hydrochloride, which
was recrystallized from 120 ml of a mixture of methanol and ethanol (1:4 by
volume ratio) to provide the colorless crystals thereof. The melting point of
the 5-{2-[2-(2-ethoxyphenoxy)ethylamino]-2-methylethyl}-2-
methoxybenzenesulfonamide hydrochloride: 254°-256°C.
Therapeutic Function
Antihypertensive
General Description
Tamsulosin hydrochloride is a subtypeselective a
1A and a
1D adrenoceptor antagonist, which exists in two enantiomeric forms, of which the
R-isomer is the pharmaceutically active component. It is used to reduce urinary obstruction and is also involved in relieving the symptoms associated with symptomatic benign prostatic hyperplasia.
Hazard
Moderately toxic by ingestion.
Biological Activity
Selective α 1A -adrenoceptor antagonist (pK i values are 9.97, 9.64 and 8.86 for α 1A , α 1B and α 1D subtypes respectively). Decreases resting maximal urethral pressure with negligable effect on mean arterial blood pressure in vivo .
Biochem/physiol Actions
Tamsulosin is an α1A/1D-adrenoceptor antagonist used as a treatment of benign prostatic hypertrophy (BPH). Its activity as an blocker also affects the iris, and has led to complications during cataract surgery, a condition called "floppy iris" syndrome.
References
[1] K HONDA. Studies on YM-12617: a selective and potent antagonist of postsynaptic alpha 1-adrenoceptors.[J]. Naunyn-Schmiedeberg’s archives of pharmacology, 1985, 328 3: 264-272. DOI:
10.1007/bf00515552[2] W. D. RATNASOORIYA R. M W. Tamsulosin, a selective α1-adrenoceptor antagonist, inhibits fertility of male rats[J]. Andrologia, 1994, 26 2: 107-110. DOI:
10.1111/j.1439-0272.1994.tb00766.x[3] K SUDOH. Effect of tamsulosin, a novel alpha 1-adrenoceptor antagonist, on urethral pressure profile in anaesthetized dogs.[J]. Journal of autonomic pharmacology, 1996, 16 3: 147-154.
