We found out our cat has a thyroid problem. We were prescribed methimazole to be taken twice a day. She was on medication for about 2 weeks and then started vomiting a few times a day and also had a red spot below her nose and experienced facial itching. We called our vet and he said to take her off the meds. She has not had any in about a day and a half but she is still vomiting. How long does methimazole stay in a cats system?