I forgot to answer your question dogtired. You asked "what is PTU". It is short for propylthiouracil. It is an antithyroid drug used for suppressing the thyroid when you have hyperthyroid or Graves disease.
That is when the thyroid is putting out too much t4. You get nervous, increased bowel movements, palpitations, shedding hair, weightloss, high blood pressure. Just the same symptoms when your getting too much t4.
I was so glad to get off of that stuff. Sometimes I would get too much(in which my ignorant doc failed to tell me) and went hypo on it.
Sorry I missed the question