Amiodarone
"Was in the hospital for AFib with RVR which came on about 3 days before an ablation procedure that had been scheduled for the AFib.  After two days of trying other drugs to keep my rate down and them working but barely the cardiac ICU decided to try this drug to break me out of the rhythm.  Apparently I'm allergic to it because within minutes of starting an IV drip of it I started getting flush and getting that same feeling as when you have the contrast dye for a CT.  Of course we immediately shut it off and there seems to be no lasting problems since I had so little of it.  Definitely can't recommend this drug unless it's an absolute last resort based on my experiences with it and everything I've read after the fact about the side effects"