タムスロシン塩酸塩

外観

白色～わずかにうすい褐色、結晶～粉末

効能

排尿障害改善薬, α1アドレナリン受容体拮抗薬

商品名

ハルナール (アステラス製薬)

説明

Tamsulosin is a potent antagonist of α₁-adrenergic receptors (α₁-ARs; K_i = 0.229 nM in a radioligand binding assay). It is 3,800-fold selective for α₁-ARs over α₂-ARs (K_i = 871 nM). Tamsulosin antagonizes norepinephrine-induced contraction of isolated rabbit aorta (pA₂ = 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.

化学的特性

White to Off-White Solid

使用

Specific a1-adrenoceptor antagonist. Used in the treatment of benign prostatic hypertrophy

一般的な説明

Tamsulosin hydrochloride is a subtypeselective a₁A and a₁D 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.

危険性

Moderately toxic by ingestion.

生物活性

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 .