What Causes Increased Swelling In Feet And Ankles After Taking Terbinafine?

I am taking terbinafine for toenail. I have had some swelling of my feet and ankles before taking the medicine. My swelling has gotten worse, including my left leg. Have been on med. x 2 months and the swelling started getting more severe during the past week. I am 81yrs.old thanx