Objective: To compare the efficacy of topical 10% nifedipine versus 5% sildenafil in patients
with secondary Raynaud's phenomenon (RP).
Methods: A randomized, double-blind, placebo-controlled pilot study took place in 10 patients
with secondary RP. Topical 10% nifedipine on one hand and 5% sildenafil on the other hand
were applied. The thumbs didn't receive any cream and served as a control group. The primary
outcome was the improvement of blood flow and vessel diameter of the digital arteries
measured by high frequency color Doppler ultrasound before and 1 hour after treatment.