What Causes Edema In Feet And Ankles?

i have edema in my feet and ankles suddenly. what could be causingi t ? nd i taKE many meds, lexapro, lotrel, vesicare, welbutrin, seroquel, narco, soma , welbutrin, and i have sudenly gained almost 12 lbs in 2 days i am also having severe hot flashes and may be starting menopaus , i am 47