take medicines termed "nitrates" (like nitroglycerin) use Avenue drugs known as "poppers" for example amyl nitrate or amyl nitrite, and butyl nitrate take any medicines known as guanylate cyclase stimulators such as riociguat (Adempas) are allergic to sildenafil, as contained in Viagra® and Revatio, or any of the substances in Viagra®.Proper stud