The efficacy of thymoxamine in primary Raynaud's phenomenon

A randomised double-blind, three-way cross-over trial comparing oral thymoxamine 40 mg, oral thymoxamine 80 mg with a matched placebo was performed in 24 patients with primary Raynaud's phenomenon. The response to treatment was objectively assessed by monitoring digital skin temperature response for 7 min after exposure to a mild cold stimulus (20 C for 1 min). Thymoxamine treatment "normalised" rewarming responses in a statistically significant number of patients (P less than 0.01). Absolute digital temperatures and maximum rewarming rates were increased and the length of the latent period reduced (P less than 0.001). These effects were more pronounced with thymoxamine 80 mg than with thymoxamine 40 mg.