2001 年 47 巻 2 号 p. 192-202
Up to the mid-1990s benign prostatic hyperplasia (BPH) was commonly treated surgically. However, surgery is associated with numerous instances of failure, high patient morbidity rates, and substantial annual costs. Tamsulosin, an α1-adrenergic receptor antagonist, was originally developed as an alternative to surgery for BPH. It significantly improves urinary obstruction by relaxing smooth muscle in the bladder neck and prostate via specific inhibition of the α1A-adrenergic receptor subtype, the predominant subtype in these tissues. However, since α1-adrenergic receptors also mediate constriction of smooth muscle in the vascular wall, extensive tests were carried out during phase III clinical trials to investigate whether tamsulosin has any effect on mediation of the cardiovascular system. Since BPH is a condition that affects men from middle age and many patients are also hypertensive, a subanalysis was carried out during these phase III clinical trials to investigate whether tamsulosin has any effect on blood pressure control or vasodilation in men who are also being treated for hypertension. During 13-week double-blind administration of once-daily tamsulosin or placebo, no statistically significant differences were observed in blood pressure or heart rate among normotensive, controlled hypertensive, and uncontrolled hyprtensive patients. The results of this study demonstrate that tamsulosin can be used in BPH patients who are hypertensive without any restrictions on blood pressure control medication.
