Synopsis: Prazosin1 is a peripheral vasodilator antihypertensive agent derived from quinazoline. Animal studies suggest that its hypotensive effect results from relaxation of peripheral arterioles as a consequence of blockade of post-synaptic α-adrenoceptors. In man, the most important haemodynamic effect is a reduction in total peripheral resistance, but in contrast to hydrallazine, tachycardia is seldom produced.

Prazosin: a review of its pharmacological properties and therapeutic efficacy in hypertension.

Prazosin [1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furoyl)-piperazine] is the first member of a new class of antihypertensive agents (fig. 1).

Prazosin: A Review of its Pharmacological Properties and Therapeutic Efficacy

1. Various theories on the origin and development of hypertension offered over the years have been assessed critically. 2. It is concluded that no one theory is adequate at the present time to encompass all the known facts. 3. Continuously expanded understanding of hypertensive mechanisms, however, help in the individualization and therefore the improvement of various modalities of therapy, including treatment with presently available agents, as well as with those which may be developed in the future.

Some theories of hypertension: fact and fancy.

Some major consequences of actions of drugs on the autonomic nervous system in man and experience of prediction from animal studies.

1. A chemical name for prazosin hydrochloride is piperazine, l-(4-amino-6,7-dimethoxy-2-quinazolinyl ) -4( 2-f uranylcarbonyl ) -, monohydrochloride. Prazosin is structurally unrelated to any other antihypertensive agent. 2. Prazosin hydrochloride is a white, crystalline powder. It is slightly soluble In water and isotonic saline solution. It is very slightly soluble in alcohol and has an apparent pKa of 6.5 in 1:1 water and ethanol solution.

Prazosin (Minipress® — Pfizer)

1. The effects of prazosin administered alone or in combination were studied in thirty patients between August 1974 and March 1975. 2. All patients had previously received treatment for hypertension with other agents, for from 2 months to 10 years. All thirty patients had refractory hypertension which had not responded satisfactorily to other treatment. 3. Patients were treated initially with prazosin; polythiazide, or polythiazide plus tolamolol, were added when necessary. 4. A satisfactory blood pressure response to prazosin alone, or prazosin in dual or triple combination therapy, occurred in all thirty patients. 5. Prazosin was well tolerated.

J. S. Kim

Papers

A Study of the use of Prazosin in Hypertensive Patients in Korea