Controlled double-blind trial of the clinical effect of nifedipine in the treatment of idiopathic Raynaud's phenomenon.

Twenty-six patients with idiopathic Raynaud's phenomenon participated in a double-blind, crossover clinical trial comparing the clinical effect of nifedipine with that of placebo. Four patients discontinued the study because of side effects and one patient defaulted at the return visit. Nifedipine significantly reduced frequency and severity of attacks (p less than 0.01). In an overall evaluation of drug effectiveness, 19 of 21 patients preferred nifedipine to placebo (p less than 0.01). Nifedipine proved to be effective in the treatment of idiopathic Raynaud's phenomenon, but side effects should be expected in some 30%.