Objective: OPC-28326 is a selective alpha-adrenergic antagonist with preferential binding to the alpha(2C)-adrenergic receptor (alpha(2C)-AR) subtype. This study observed the effect of OPC-28326 on skin temperature and digital blood flow following an acute cold challenge in patients with Raynaud's phenomenon secondary to scleroderma.
Methods: The study was designed as a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of OPC-28326 (oral doses of 10 mg or 40 mg) or placebo.