Objective: Raynaud's phenomenon is a relatively common disorder for which highly effective, well tolerated treatment has yet to be developed. Minoxidil, a potent vasodilator which, on a single application to the scalp causes significant local cutaneous vasodilation, was selected for study in primary Raynaud's phenomenon.
Methods: Ten subjects were enrolled in a randomized double blind, placebo controlled acute challenge crossover trial. Single applications of topical minoxidil 5% solution and placebo were made to each subject's fingers on 2 separate occasions, and measures of digital skin temperature, systolic blood pressure, and laser Doppler flow were obtained, before and after acute cold challenge.
Results: Digital skin temperature, systolic blood pressure, and laser Doppler flow both before and after cold challenge were not improved by pretreatment with topical minoxidil 5% solution.
Conclusion: In individuals with primary Raynaud's phenomenon, a single application of minoxidil 5% solution to the fingers is not effective in improving baseline digital blood flow or cold tolerance.