Doxazosin Mesylate (doxazosin mesylate)

Doxazosin mesylate is a quinazoline-derivative postsynaptic alpha1-adrenergic blocking agent.

Doxazosin mesylate is a quinazoline-derivative postsynaptic alpha1-adrenergic blocking agent. The drug is chemically and pharmacologically related to prazosin and terazosin. On a weight basis, the postsynaptic alpha1-adrenergic blocking potency of doxazosin is half that of prazosin, and the alpha1-receptor selectivity is one-fourth that of terazosin when tested in human prostate adenoma.

Doxazosin reduces peripheral vascular resistance and blood pressure as a result of its vasodilating effects; the drug produces both arterial and venous dilation. Doxazosin reduces blood pressure in both supine and standing patients; the effect is most pronounced on standing blood pressure, and postural hypotension can occur. Doxazosin generally causes no change in heart rate or cardiac output in the supine position.

Cardiovascular responses to exercise (e.g., increased heart rate and cardiac output) are maintained during doxazosin therapy.

Effects of doxazosin on the cardiovascular system are mediated by the drug's activity at alpha1-receptor sites on vascular smooth muscle. alpha1-Adrenergic receptors also are located in nonvascular smooth muscle (e.g., bladder trigone and sphincters, GI tract and sphincters, prostate adenoma and capsule, ureters, uterus) and in nonmuscular tissues (e.g., CNS, liver, kidneys). Because of the prevalence of alpha-receptors on the prostate capsule, prostate adenoma, and the bladder trigone and the relative absence of these receptors on the bladder body, alpha-blockers decrease urinary outflow resistance in men.

Doxazosin may improve to a limited extent the serum lipid profile (e.g., small increases in high-density lipoprotein cholesterol concentrations (HDL) and HDL/total cholesterol ratio, small decreases in low-density lipoprotein cholesterol (LDL), total cholesterol, and triglyceride concentrations), and can reduce blood glucose and serum insulin concentrations. The drug does not appear to affect plasma renin activity appreciably.

Commercially available extended-release tablets of doxazosin mesylate (Cardura(R) XL) contain the drug in an oral osmotic delivery system formulation (elementary osmotic pump, GI therapeutic system (GITS)). The osmotic delivery system consists of an osmotically active core (comprised of a layer containing the drug and a layer containing osmotically active but pharmacologically inert components) that is surrounded by a semipermeable membrane with a laser-drilled delivery orifice and is designed to deliver the drug at an approximately constant rate over a 24-hour period (approximately zero-order delivery). The inert tablet ingredients remain intact and are eliminated in feces.

Oral bioavailability from extended-release tablets at steady state with 4- or 8-mg doses is 54 or 59%, respectively, of that achieved with conventional (immediate-release) tablets. Food increases peak plasma concentrations and bioavailability achieved with extended-release tablets.

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USES: This medication is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Doxazosin belongs to a class of drugs known as alpha blockers.

It works by relaxing blood vessels so blood can flow more easily. Doxazosin is also used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia-BPH). It does not shrink the prostate, but it works by relaxing the muscles in the prostate and part of the bladder.

This helps to relieve symptoms of BPH such as difficulty in beginning the flow of urine, weak stream, and the need to urinate often or urgently (including during the middle of the night).

Generic name: doxazosin mesylate
Pronunciation: (dox-AZE-oh-sin)

The following indications are listed for Doxazosin Mesylate:

• Benign Prostatic Hyperplasia With Lower Urinary Tract Symptom
• Hypertension

Also known as: Elevated Blood Pressure, Essential Hypertension, Hyperpiesia, Hyperpiesis, Hypertensive Disorder, Symptomatic Benign Prostatic Hyperplasia, Symptomatic Benign Prostatic Hypertrophy, Symptomatic Bph, Symptomatic Prostatic Hypertrophy, Systemic Arterial Hypertension.

No ICD codes are available for this drug.