Neo-Synephrine and heart rate

I took Neo 12 hour twice in the prescribed 24 hour period. I noticed the next morning that my heart rate was elevated upon rising, and while taking a shower, noticed that I was having lots of palpitations or "skipped beats" followed by a refreshing feeling...you know, the feeling you get after you hold your breath for a minute and then let it out and take a deep breath. I didn't think the episode was due to the Neo 12 hour, but changed to the Neo 4 hour because I wanted the stuffy head/nose to clear up sooner than 12 hours. I wanted to know if the Neo could interact with Sudafed or not, and if so, could it cause this problem to be worse than just one of these meds by itself?