Check YOURSELF for allergies. I tried the Nizoral shampoo and almost killed myself doing it. It turns out I am highly allergic to it. I was borderline anaphylactic shock when I got to the ER. My airways were closing and my throat and tongue were swelling rapidly. They tubed me in the ambulance, and I got lucky that one of the EMT's was a horse person and recognized the smell of the shampoo to give my ER Doctor a heads up on one possible cause of the reaction. It turns out he was right.
A good friend of mine is severely allergic to MTG. The sulfur in it makes her break out in hives and itch like a mangy dog! When her guys need MTG she calls me. I use that stuff on the dogs, the horse, and I've even used it on the hubby LOL.