I had open heart surgery in 98 2 valve replacements stainless steele valves. I've been on furosemide 80 mg. along with potassium all this time. I've had 3 different heart Dr.'s. Now I get a new GP Dr. and he thinks all of a sudden the dosage is to high. Why? I've been on it sense 1998, and do testing every 6 months for that and the other meds I'm on.