ALPHA-BLOCKADE AND BETA-BLOCKADE AND BETA-STIMULATION IN RAYNAUDS SYNDROME - A DOUBLE-BLIND, PLACEBO CONTROLLED, SINGLE DOSE STUDY

In a double blind fashion and placebo control 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) was studied in 12 patients with Raynaud''s syndrome. A favorable 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.-agonist (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 1 collapse and 3 near-collapses. On alpha-blocker and beta-blocker (phenoxybenzanine 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 after the addition of propranolol to the alpha-blocker phenoxybenzamine. An alpha-blocker is apparently a good choice in Raynaud''s syndrome whereas the addition of a beta-blocker may have some advantages.