I think Sudafed is more of a problem for people who are hyperthyroid. Sudafed contains an ingredient called ephidrine (something like that) which is a stimulant, and makes your heart race if you’re already hyper. (Before I was diagnosed with Grave’s, I had an unpleasant experience with an over-the-counter cold med with ephidrine. I was awake and jittery for about 20 hours after taking it. Horrible feeling!)
My doctor has told me recently not to worry about OTC cold medicines at this point (I’m euthyroid), but I had such a miserable time last time I took cold medicine, that I prefer just to use other things when I have a cold (I find tea, Plain Robitussin cough syrup (Guaifenesin), and Vicks Vap-O-Rub work well for me).
Regarding echinacea, there was an article in the current Harvard Women’s Health Newsletter (which you can find on the internet) that warns against using echinacea if you have autoimmune disease — so that might apply whether you’re hyper or hypo. The major point of the article, however, was that there’s little uniformity across echinacea and other herbal meds, even within the same brand, and little good research to indicate appropriate doses and effectiveness. Given that, I think it makes sense to stay away from herbal stuff too.
