Hi and thanks for the regimen, the abrupt change in the usual regimen could explain symptoms. However, presence of additional clinical features such as diarrhea accompanied by fever, ankle pain and chill need further evaluation. An acute infectious cause needs to be excluded. I suggest a consultation with your primary care physician for blood tests to be run in order to exclude possible infections and acute inflammatory conditions. A control of levels of thyroid hormones is also very necessary. i suggest he should not change his treatment regimen without prior discussion with his treating physician, for this could have very negative consequences at times. Thanks and hope this helps, Best regards, luchuo, MD.