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Hemodynamic Interaction Between a Daily Dosed Phosphodiesterase 5 Inhibitor, Tadalafil, and the α‐Adrenergic Blockers, Doxazosin and Tamsulosin, in Middle‐Aged Healthy Male Subjects
Author(s) -
Guillaume Michel,
Lonsdale Finnuala,
Darstein Christelle,
Jimenez Maria C.,
Mitchell Malcolm I.
Publication year - 2007
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1177/0091270007306559
Subject(s) - doxazosin , tadalafil , tamsulosin , placebo , blood pressure , medicine , urology , anesthesia , hemodynamics , crossover study , erectile dysfunction , alternative medicine , pathology , hyperplasia
The hemodynamic interaction between tadalafil (5 mg/d) and doxazosin or tamsulosin was investigated in 2 randomized, double‐blind, crossover phase 1 studies. Healthy men (n = 45) received tadalafil or placebo for 28 days and increasing doses of doxazosin (1, 2, and 4 mg/d) for the last 21 days of treatment. In the second study, participants (n = 39) received tadalafil or placebo for 14 days and tamsulosin (0.4 mg/d) for the last 7 days of treatment. Similar mean maximum postbaseline changes in standing systolic blood pressure were observed in subjects given tadalafil or placebo with 4 mg of doxazosin (−0.5 mm Hg; 95% confidence interval, −4 to 3.1 mm Hg) or with tamsulosin (0.9 mm Hg; 95% confidence interval, −1.4 to 3.2 mm Hg). Standing systolic blood pressure less than 85 mm Hg (blood pressure outlier) occurred in 1 subject treated with 4 mg of doxazosin plus tadalafil but was not reported in subjects treated with tamsulosin and tadalafil. Three subjects experienced moderate hypotensive events lasting less than 2 hours, 2 with syncope (after tadalafil alone or with 4 mg of doxazosin) and 1 without (after 4 mg of doxazosin with placebo). The incidence of hypotension was low in healthy men given increasing doses of doxazosin with chronically dosed tadalafil or placebo. Administration of tadalafil with tamsulosin was well tolerated in healthy men.