Biomaterial Database

Effects of doxazosin on exercise-induced angina pectoris, ST-segment depression, and insulin sensitivity in patients with syndrome X. 1998

H E Bøtker, and H S Sonne, and O Schmitz, and T T Nielsen

Department of Cardiology, Skejby Hospital, University Hospital in Aarhus, Denmark. skejhb@aau.dk

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.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D001786	Blood Glucose	Glucose in blood.	Blood Sugar,Glucose, Blood,Sugar, Blood
D004311	Double-Blind Method	A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.	Double-Masked Study,Double-Blind Study,Double-Masked Method,Double Blind Method,Double Blind Study,Double Masked Method,Double Masked Study,Double-Blind Methods,Double-Blind Studies,Double-Masked Methods,Double-Masked Studies,Method, Double-Blind,Method, Double-Masked,Methods, Double-Blind,Methods, Double-Masked,Studies, Double-Blind,Studies, Double-Masked,Study, Double-Blind,Study, Double-Masked
D005260	Female		Females
D005951	Glucose Tolerance Test	A test to determine the ability of an individual to maintain HOMEOSTASIS of BLOOD GLUCOSE. It includes measuring blood glucose levels in a fasting state, and at prescribed intervals before and after oral glucose intake (75 or 100 g) or intravenous infusion (0.5 g/kg).	Intravenous Glucose Tolerance,Intravenous Glucose Tolerance Test,OGTT,Oral Glucose Tolerance,Oral Glucose Tolerance Test,Glucose Tolerance Tests,Glucose Tolerance, Oral
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000317	Adrenergic alpha-Antagonists	Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.	Adrenergic alpha-Receptor Blockaders,alpha-Adrenergic Blocking Agents,alpha-Adrenergic Receptor Blockaders,alpha-Blockers, Adrenergic,Adrenergic alpha-Blockers,alpha-Adrenergic Antagonists,alpha-Adrenergic Blockers,Adrenergic alpha Antagonists,Adrenergic alpha Blockers,Adrenergic alpha Receptor Blockaders,Agents, alpha-Adrenergic Blocking,Antagonists, alpha-Adrenergic,Blockaders, Adrenergic alpha-Receptor,Blockaders, alpha-Adrenergic Receptor,Blockers, alpha-Adrenergic,Blocking Agents, alpha-Adrenergic,Receptor Blockaders, alpha-Adrenergic,alpha Adrenergic Antagonists,alpha Adrenergic Blockers,alpha Adrenergic Blocking Agents,alpha Adrenergic Receptor Blockaders,alpha Blockers, Adrenergic,alpha-Antagonists, Adrenergic,alpha-Receptor Blockaders, Adrenergic
D015444	Exercise	Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.	Aerobic Exercise,Exercise, Aerobic,Exercise, Isometric,Exercise, Physical,Isometric Exercise,Physical Activity,Acute Exercise,Exercise Training,Activities, Physical,Activity, Physical,Acute Exercises,Aerobic Exercises,Exercise Trainings,Exercise, Acute,Exercises,Exercises, Acute,Exercises, Aerobic,Exercises, Isometric,Exercises, Physical,Isometric Exercises,Physical Activities,Physical Exercise,Physical Exercises,Training, Exercise,Trainings, Exercise