Doxazosin

Doxazosin is a drug from the group of alpha-blockers (selective α1 receptor blockers) used to treat benign prostatic hyperplasia and arterial hypertension. The substance has the molecular formula C23H25N5O5 and a molecular weight of 451.475 g/mol.

Selective α1 receptor anatgonists have prevailed in pharmacotherapy over the non-selective α receptor antagonists and block the alpha1-adrenoreceptors. These belong to the adrenoreceptors (G-protein-coupled receptors) and can be detected mainly in the presynaptic membrane of sympathetic and also parasympathetic neurons, but also on the cell membrane of adipocytes.

Adrenoceptors are activated by the accumulation of catecholamines (adrenaline and noradrenaline). α 1-Arenoceptors contribute to the regulation of sympathetic nervous system activity and influence a number of sympathetic reactions, for example to smooth muscles in vessels, bronchial tubes, hair follicles (goose bumps), the urogenital tract and the gastrointestinal tract. They unfold their effect via the Gq protein (see below G-protein coupled receptors see below adrenoreceptors). All α 1-receptor antagonists were primarily developed as antihypertensives, but today they do not belong to the first-line antihypertensives, as they promote rather than prevent the development of cardiovascular secondary diseases (secondary disease of hypertension = heart failure).

By binding to alpha-1 receptors in the cardiovascular system and urogenital tract, Doxazosin prevents the neurotransmitters adrenaline or noradrenaline from binding to these receptors. This suppresses their effect. The result is a blood pressure-lowering effect. Doxazosin also reduces muscle tone in the bladder neck and in the prostate tissue itself.

The most common side effects of Doxazosin include drowsiness, low blood pressure, abdominal cramps and indigestion.

Cardular® PP

The active ingredient is contained in medicines as doxazosin maleate. Doxazosin can be used as monotherapy or in combination with another drug, e.g. a thiazide diuretic, a beta-blocker, a calcium antagonist or an ACE inhibitor.

1. Graefe KH et al. sympathetic nervous system. In: Graefe KH et al (Eds) Pharmacology and Toxicology. Georg Thieme Publisher Stuttgart S.98