Document Detail

Effects of doxazosin on exercise-induced angina pectoris, ST-segment depression, and insulin sensitivity in patients with syndrome X.
MedLine Citation:
PMID:  9856918     Owner:  NLM     Status:  MEDLINE    
A significant proportion of patients with cardiac syndrome X have impaired coronary vasodilator capacity, which is thought to be caused by an increased sympathetic drive. The alpha1-adrenoceptor blocker, doxazosin, increases the coronary vasodilator reserve in patients with syndrome X. To study whether the augmentation is associated with clinical improvement in patients, we conducted a double-blind, placebo controlled, crossover study with doxazosin 1 to 4 mg once daily for 10 weeks in 16 patients with syndrome X (14 women and 2 men; mean +/- SD age 56+/-5 years). Time to angina, exercise duration, time to 0.1 mV ST-segment depression, and maximal ST-segment depression during bicycle exercise testing were compared after treatment with doxazosin 2 mg or placebo for 5 weeks and again after treatment with doxazosin 4 mg or placebo for 10 weeks. Insulin sensitivity was assessed by the minimal model after 10 weeks of doxazosin or placebo treatment. Twelve patients completed the protocol. Doxazosin 4 mg/day decreased systolic blood pressure at rest (109+/-16 vs 125+/-18 mm Hg, p <0.05) and increased basal heart rate (85+/-9 vs 76+/-11 beats/min, p <0.05), whereas hemodynamics were unaffected during exercise. Time to angina, exercise duration, time to 0.1 mV ST-segment depression, and maximal ST-segment depression were similar during treatment with doxazosin and placebo irrespective of the doxazosin dose. Insulin sensitivity was not different with doxazosin and placebo. In conclusion, alpha1 blockade does not significantly improve exercise duration, angina pectoris, and ST-segment depression despite a favorable vasodilator effect in patients with syndrome X. The absent clinical efficacy of doxazosin may challenge the use of the coronary vasodilator capacity as an appropriate method to subclassify patients with syndrome X.
H E Bøtker; H S Sonne; O Schmitz; T T Nielsen
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of cardiology     Volume:  82     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1998 Dec 
Date Detail:
Created Date:  1998-12-21     Completed Date:  1998-12-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1352-6     Citation Subset:  AIM; IM    
Department of Cardiology, Skejby Hospital, University Hospital in Aarhus, Denmark.
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MeSH Terms
Adrenergic alpha-Antagonists / therapeutic use*
Blood Glucose / analysis
Cross-Over Studies
Double-Blind Method
Doxazosin / therapeutic use*
Glucose Tolerance Test
Insulin / blood,  diagnostic use
Microvascular Angina / blood,  drug therapy*,  etiology,  physiopathology
Middle Aged
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Blood Glucose; 11061-68-0/Insulin; 74191-85-8/Doxazosin

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