A2-Adrenergic Function in Raynaud's Disease

Abstract

To the Editor.— I read with interest the recent review article on Raynaud's phenomenon by Klippel. 1 The author correctly states that we were able to provoke cold-induced vasospastic attacks in patients with primary Raynaud's disease whose digital nerves had been blocked by lidocaine. 2 However, Klippel's account of our findings on α 2 -adrenergic function in Raynaud's disease is incorrect. We performed brachial artery infusions of clonidine hydrochloride (0.25 to 4.0 μg/min) in eight patients with Raynaud's disease and in 11 normal volunteers. 3 Patients with Raynaud's disease had significantly greater vasoconstriction than did control subjects at all doses that were administered. These findings were independently replicated. 4 Lindblad et al 5 delivered an α 2 agonist by iontophoresis, which perfused only a small area of skin and cannot assure accurate drug delivery. 5 In contrast, we 3 and others 4 administered clonidine hydrochloride by pump through the brachial