I have Graves disease dxd Dec 2007, and have been on PTU since then and until about 2 weeks ago was feeling great. My last blood test was in Feb & all levels were normal. Then, about 2 weeks ago, I got the flu & took some over the counter cold & flu medicine. After taking it, I actually read the box & it said not to take if you have thyroid disease. Ever since then, I feel as if some of my symptoms are coming back (rapid heartbeat, anxiety, insomnia). I called my Endo & he is going to do another blood test, but do you think the cold/flu medicine can cause some kind of flare up in my Hyperthyroid symptoms?