Therapeutic effects of intraarterial phentolamine in "Raynaud's syndrome".

Five patients suffering from "Raynaud's syndrome" were studied as regards the effects of increasing doses of intraarterially administered phentolamine on the blood flow to the digital arteries. Upon angiography they had shown multiple occlusions of their digital arteries. Venous occlusive plethysmography of the forearm, volume pulse amplitude of a finger tip of treated and untreated extremity, respectively, intraarterial pressure in the brachial artery and ECG lead II have been monitored continuously. The blockade of the alpha-adrenoceptors by phentolamine resulted in a favourable effect upon the accompanying functional component: The volume pulse amplitude of and the blood flow to the treated extremity increased considerably, without significant changes in the other hemodynamic parameters upon administration of doses up to 0.5 mg of phentolamine. A dose of 0.5 to 1.0 mg of phentolamine seems to be the optimum, higher doses yielding no better results. The effective blockade of the alpha-adrenoceptors could be demonstrated by the influence on the arterial blood pressure during a Valsalva maneuver, on the venous reflex response, and the diminished effectiveness of noradrenaline in the treated extremity.