Prazosin Update A Review of its Pharmacological Properties and Therapeutic Use in Hypertension and Congestive Heart Failure

Abstract

Prazosin is an orally active post-synaptic selective alpha 1-adrenoreceptor antagonist that has been widely used in treating hypertension and congestive heart failure (CHF). Its role in the treatment of hypertension has previously been reviewed in this journal. Subsequent reports confirm its efficacy in treating mild to severe hypertension as a single agent or, more frequently, in combination with another antihypertensive agent and/or a diuretic. Recent studies of the metabolic effect of prazosin indicate that the drug may have a favourable effect on plasma lipids in hypertensive patients. Its recent use in treatment of congestive heart failure has shown prazosin to be comparable with nitroprusside in producing balanced arterial and venous dilation with generally sustained haemodynamic and clinical effects during long term therapy. Initial studies in Raynaud's phenomenon and in patients with aortic regurgitation or aortic stenosis or with mitral regurgitation are promising, but require confirmation from wider clinical experience. The drug has generally been well tolerated. The primary side effect of orthostatic hypotension can be largely avoided by beginning treatment with a low dose.

The potential for prazosin and calcitonin gene-related peptide (CGRP) in causing hypoxia in tumours

“…BURNEY et al Prazosin may not be suitable for clinical use as a modifier of tumour blood flow because of its long half life (see Table III). The hypotensive effects may last for up to 10-12 h (Stanaszek et al, 1983). Faintness and dizziness have been reported to occur in 50% of patients receiving this drug.…”

“…Prazosin blocks the action of nor-epinephrine by post-synaptic receptor blockade and subsequently decreases its further release through negative feed back control (Stanaszek et al, 1983). CGRP causes sympathetic stimulation (Fisher et al, 1983), increasing the nor-epinephrine release by almost 2-fold.…”

Metabolism of Prazosin in Rat, Dog, and Human Liver Microsomes and Cryopreserved Rat and Human Hepatocytes and Characterization of Metabolites by Liquid Chromatography/Tandem Mass Spectrometry

“…1), a short-acting vasodilator discovered in the mid1970s, has been widely used in treating hypertension and congestive heart failure (Constantine, 1974;Althuis and Hess, 1977;Stanaszek et al, 1983). It was the first of a new class of direct-acting vasodilators acting by ␣-adrenoreceptor blockade.…”

The management of hypertension.

“…Many open studies have evaluated the effect of prazosin in hypertension (Stanaszek et al, 1983). Other related quinazoline a-adrenoceptor blocking drugs have been found effective antihypertensives, trimazosin (Weber et al, 1982;Taylor et al, 1983), diazosin (de Leeuw et al, 1982), and terazosin (Nelson et al, 1982;Drayer et al, 1983).…”