I can just tell about myself, n=1. I have no problems with POTS, but I do have PEM. Is there possibly a difference in POTS symptoms (as well as there are others that differ) due to the kind of Borrelia bacterias that caused the Lyme infection? I agree that your dose @duncan sounds very high, at least according to Dr Horowit´s protocol. ( On page 104 in his latest book he says that the full dose is 100 mg , but it may take months for some patients to get to the full dose due to Herx...reactions. He normally increases the dose slowly, at least over two weeks, from 25 mg to 100 mg daily. There are also other antibiotics that are used in the protocol to get the best effect. FWIW and if you didn´t already know this).