There is some empirical evidence to limit the amount of Flecainide a person should take before resorting to other measures. I am not up on that as it isn't in my history. One person on affibers.org has controlled his AF amazingly well by diet, avoiding higher than Zone 2 aerobic exercise, drinking copious quantities of magnesium-laced concoctions, and other dietary measures (limiting his calcium intake is another). He keeps 200 mg of Flecainide on his person per PIP. He has about one breakthrough each year, and that protocol works very well for him. He points out on that forum when dealing with inquiries that people below a certain body weight should not take the upper/max possible dose for Flecainide. I don't recall, sorry, what the numbers are, but it seems to me 150 mg would be the upper limit for someone lighter than about 150 pounds, so the typical teenager/woman.