Pentoxifylline has been shown in animal studies to potentially reduce the development of the Peyronie’s scar when the animals consumed the Pentox in their drinking water from the time that the Peyronie’s process is triggered. Pentoxifylline is indicated to enhance blood flow to the lower extremities in patients with peripheral vascular disease likely because it has a mild non-specific vasodilating effect. Therefore, it is possible that it can increase blood flow in the man with PD. As to whether this will improve erections or has anything to do with preventing progression of already established PD is unknown. Niacin, to my knowledge, has not been studied as a treatment for Peyronie’s disease.