Not sure if this is news to anyone.
I was on slow release Tambocor (flecainide) [CR next to the pill name] from October until recently. Initially i was on 200mg (one pil), then down to 100mg. Recently I went into A-fib while taking 100mg and was cardioverted for the 4th time. Now I am on 100mg quick release [I think there is a DR next to the name] twice a day, plus a beta blocker.
When I was on the slow release I felt strange more often than I felt normal. This was especially the case on 100mg; surprisingly, on 200mg I was generally fine.
However now that I am on the quick release version it seems like I feel fine all the time! This is so much better!