Effects of phosphodiesterase type 5 inhibitors on Raynaud’s phenomenon

Raynaud’s phenomenon (RP) is commonly observed in fingers and toes of patients with connective tissue diseases (CTDs). However, existing vasodilators have very limited efficacy. In this study, phosphodiesterase type 5 inhibitors (PDE-5Is) were administered to evaluate efficacy on RP. Three patients with mixed connective tissue disease and three patients with systemic sclerosis having RP were enrolled. Oral sildenafil, vardenafil, or tadalafil was administered. The fingertip temperature was measured by thermography before and 120 min after administration. To evaluate longer effects, vardenafil was administered daily for 12 weeks; the fingertip temperature was measured by thermography before and 12 weeks after administration. As compared with the pre-administration of sildenafil, vardenafil, and tadalafil, the mean fingertip temperature increased by 2.17, 3.47, and 3.59 °C, respectively, in 120 min. In the 12-week trial with vardenafil in 3 patients, the mean fingertip temperature increased by 3.04, 7.96, and 3.32 °C from baseline in each patient. PDE-5Is significantly increased fingertip temperature within 120 min, and the effect of vardenafil lasted for 12 weeks under daily use. PDE-5Is were safe and would be an effective treatment for RP with CTDs.