Doxazosin
Encyclopedia
Doxazosin mesylate, a quinazoline
compound sold by Pfizer
under the brand names Cardura and Carduran, is an α1a-selective alpha blocker
used to treat high blood pressure and urinary retention associated with benign prostatic hyperplasia
(BPH).
On February 22, 2005, the US
FDA
approved a sustained release form of doxazosin, to be marketed as Cardura XL.
It is an alpha-1 adrenergic receptor blocker
that inhibits the binding of norepinephrine
(released from sympathetic nerve terminals) to the alpha-1 receptors
on the membrane of vascular smooth muscle
cells. The primary effect of this inhibition is relaxed vascular smooth muscle
tone (vasodilation
), which decreases peripheral vascular resistance, leading to decreased blood pressure
.
In Egypt, tablet formulation sold as Duracin produced by Biopharm group for research and the drug industry, Dosin by Eipico and Doxazocine by Multi-Apex.
, and because patients on Cardura had a 25% higher rate of cardiovascular disease
and twice the rate of congestive heart failure
as patients on diuretics. Pfizer, aware of the results before publication, launched a sophisticated damage-control campaign in early 2000, and sales were largely unaffected, despite the dangers highlighted by the study.
Recent Studies have given new rise to a preference for Doxazosin as a BPH Drug, as it was found to treat erectile dysfunction (ED). The company’s own study did not yield as statistically significant results; however, Doxazosin does show promise for men with BPH and ED.
Quinazoline
Quinazoline is a compound made up of two fused six-membered simple aromatic rings, a benzene ring and a pyrimidine ring. Its chemical formula is C8H6N2. Quinazoline is yellow and crystalline...
compound sold by Pfizer
Pfizer
Pfizer, Inc. is an American multinational pharmaceutical corporation. The company is based in New York City, New York with its research headquarters in Groton, Connecticut, United States...
under the brand names Cardura and Carduran, is an α1a-selective alpha blocker
Alpha blocker
Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
used to treat high blood pressure and urinary retention associated with benign prostatic hyperplasia
Benign prostatic hyperplasia
Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....
(BPH).
On February 22, 2005, the US
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
FDA
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
approved a sustained release form of doxazosin, to be marketed as Cardura XL.
It is an alpha-1 adrenergic receptor blocker
Alpha blocker
Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
that inhibits the binding of norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
(released from sympathetic nerve terminals) to the alpha-1 receptors
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
on the membrane of vascular smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
cells. The primary effect of this inhibition is relaxed vascular smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
tone (vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
), which decreases peripheral vascular resistance, leading to decreased blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
.
In Egypt, tablet formulation sold as Duracin produced by Biopharm group for research and the drug industry, Dosin by Eipico and Doxazocine by Multi-Apex.
Efficacy
In March 2000, the ALLHAT study stopped its arm of the trial looking at alpha blockers, because doxazosin (Cardura) was less effective than a simple diureticDiuretic
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...
, and because patients on Cardura had a 25% higher rate of cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
and twice the rate of congestive heart failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
as patients on diuretics. Pfizer, aware of the results before publication, launched a sophisticated damage-control campaign in early 2000, and sales were largely unaffected, despite the dangers highlighted by the study.
Recent Studies have given new rise to a preference for Doxazosin as a BPH Drug, as it was found to treat erectile dysfunction (ED). The company’s own study did not yield as statistically significant results; however, Doxazosin does show promise for men with BPH and ED.