My son was dx with PSC a little over a year ago at the age of 14. I convinced his local specialist to prescribe him vancomycin. His doctor started out with vancomycin 125mg three times daily. I knew this was below the therapeutic dose but intended for this to be a step in the right direction. My son’s symptoms did not improve so I convinced his doctor to increase the dose to vancomycin 500mg three times a day. The insurance has, thankfully, paid for the medication thus far. However, there was a scare a few weeks ago when the pharmacy billed the wrong insurance and informed his doctors office that a prior authorization was needed. Instead of doing the prior authorization, the doctor said to decrease the medication back to the approved 125 mg three times daily. It is my understanding that anything under 1500 mg is futile and I explained this to his physician. In the meantime, the miscommunication about his insurance was corrected and he was able to continue taking vancomycin 1500 mg daily. Also, I spoke with the pharmacy and he takes vancomycin from the manufacturer Ani (I read that was important). Unfortunately, my son’s symptoms haven’t improved. In fact, he is missing more days of school. Previously, he was missing one or two days. Now he is missing up to 3 days. He c/o of a balloon feeling in his stomach, diarrhea, abdominal pain, and extreme fatigue. I should mention that my son is also dx with Crohn’s disease. I’m worried and asked his doc to do laboratory work but he said he doesn’t feel that it is indicated at this time. He has been on vanco for a couple months now without any improvement or laboratory work. My question is: Should there be routine laboratory test performed while on vancomycin medication therapy? If so, which laboratory tests are important? How long should someone continue to take vancomycin if symptoms do not improve? I appreciate any help.