Alpha and beta-blockade and beta-stimulation in Raynaud's syndrome: a double-blind, placebo controlled, single dose study

Abstract

We examined in a double blind fashion and placebo controlled the effects of some alpha and beta adrenergic receptor agonists and antagonists on the recovery of finger skin temperature 12 min after finger cooling (5 min waterbath for both hands) in twelve patients with Raynaud's syndrome. A favourable effect was established on phenoxybenzamine 20 mg as compared to placebo. A significant but rather small effect on orciprenaline 10 mg. The beta-agonists prenalterol (10 mg) and terbutaline (5 mg) did not influence the recovery of finger skin temperature. The beneficial effect of phenoxybenzamine 20 mg was not influenced by the addition of beta-agonists (prenalterol 10 mg or terbutaline 5 mg) or a beta-blocker (propranolol 40 mg). The beta-agonists terbutaline and orciprenaline caused a fall in diastolic pressure and an increase in heart rate. These effects presumably were connected with one collapse and three near-collapses. On alpha- and beta-blocker (phenoxybenzamine and propranolol) a decrease in systolic pressure appeared, whereas diastolic pressure did not significantly differ from the placebo value. While physical exercise is considered to exacerbate the hypotensive effect of alpha-blockers, a fall in blood pressure during physical exercise could not be established in our experiments after the addition of propranolol to the alpha-blocker phenoxybenzamine. Our results suggest that an alpha-blocker is a good choice in Raynaud's syndrome, whereas the addition of a beta-blocker may have some advantages.