My father has been on blood pressure meds for as long as I can remember. Lately, he will go 6 to 8 months on bp meds and everything is fine. Then out of no where, for no reason anyone can figure out it sky rockets. We go to the ER, they lower his bp meds, and within 3 weeks, his blood pressure is way too low and he is passing out. We've been on this merry go round for about 2 years now. Any idea what could be causing this?