[Alpha blockers and microcirculation (author's transl)]

The new compounds such as Prazosin are antihypertensive agents. Their action on blood pressure are a consequence of a direct action on vascular smooth muscle with little or no effect on cardiac output. This action is very important to reduce total peripheral resistance. In our Vascular Laboratory, we study 14 patients treated by Prazosin. They were all studied by capillaroscopy, ultrasonic investigations and plethysmography. Since Prazosin is primarily an alpha receptor blocker, it might be expected to have an action in microcirculation and in vasospastic diseases. We don't find modifications of microcirculation in seven people treated for hypertensive disease. Among seven patients with Raynaud phenomenon, we have only a good result in one case (Buerger disease) and two cases with a little increase of the fingertips blood flow.