While on digitalis, you should also avoid caffeine and should not take diet pills, laxatives, or cough, cold, and sinus medicines. What else should I tell my doctor? Talk to your doctor about your medical history before you start taking digitalis. The risks of taking the medicine need to be weighed against its benefits. Here are some things to consider if you and your doctor are deciding whether you should take digitalis. 1  You have allergies to digitalis medicines or allergies to foods or dyes. 2  You are thinking of becoming pregnant, you are pregnant, or you are breast feeding your baby. 3  You are over 60 and are underweight or frail.