are allergic to sildenafil, as contained in VIAGRA and Revatio®, or any of the ingredients in VIAGRAConsequences of Other Medicine on VIAGRA Sildenafil metabolism is principally mediated by CYP3A4 (main route) and CYP2C9 (insignificant route). For that reason, inhibitors of these isoenzymes may possibly decrease sildenafil clearance and inducers o