> My father usually becomes unconscious when he is sitting in a position for a > while, not when he is standing up or sitting down. He has asked his > physician in Vietnam, but the physician has no idea what's going on with my > father. He still advise my father to take Sinemet 25/100 mg, 3 tablet a day. Yen, I'm sorry to hear about your father's continued problems. It would seem that, for some reason, his blood pressure is very, very low. Sinemet can cause such difficulties - but so can a variety of other problems, including undiagnosed heart and heart valve diseases. I'm wondering if your father would do better on a lower dose of Sinemet - like half a tablet. Ask his neurologist if such a switch in treatment is advisable. In the meantime, it would be beneficial to know what your father's blood pressure is at various times of the day - and whether a drop in blood pressure is related to when he takes Sinemet. Is it possible for someone to take his blood pressure. ----- God bless Mary Ann