I Am Taking Dioxin 0.125 Mg And My Cardiologist Recently

I am taking dioxin 0.125 mg and my cardiologist recently took me off sotalol and put me on multaq 400 mg. for atriel fib. The pharmacist would not fill the prescription for multaq saying it was dangerous to take it with dioxin. I have been unable to find this dangerous warning. Dioxin slows down my heart rate. Multaq helps me stay in sinus rhythm. I need both drugs. What do you know about this problem? Pat Kellogg email YYYY@YYYY