A Comparison of the Antagonistic Activities of Tamsulosin and Terazosin Against Human Vascular α_1-Adrenoceptors

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Author(s)

Abstract

Tamsulosin, a selective α<SUB>1A</SUB>-adrenoceptor antagonist, and terazosin, a non-selective one, are effective for the treatment of urinary disturbance due to benign prostatic hypertrophy. In the present study, their α<SUB>1</SUB>-adrenoceptor-blocking effects on blood vessels, which may cause orthostatic hypotension, were investigated in 10 healthy males. After the subjects took orally 0.2 mg of tamsulosin, 1 mg of terazosin or a lactate capsule as the control in a randomized cross-over fashion, their finger tip vasoconstrictor response to cold stimulation and vasoconstrictor response of the dorsal hand vein to increasing doses of phenylephrine were examined. The finger tip vasoconstrictor response was significantly reduced and the infusion rate of phenylephrine producing a half-maximal constriction was significantly increased by terazosin, but tamsulosin had no significant effect on these parameters. These data suggest that the usual dose of tamsulosin exerts little α<SUB>1</SUB>-adrenoceptor-blocking activity on blood vessels, and orthostatic episodes might be mild, if any, during the treatment with tamsulosin.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 80(3), 209-215, 1999-07

    The Japanese Pharmacological Society

References:  39

Cited by:  1

Codes

  • NII Article ID (NAID)
    10008195191
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00215198
  • NDL Article ID
    4806254
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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